EAT CARBOHYDRATES, GET THIN (AND HEALTHY) by Magda Robinson

EAT CARBOHYDRATES, GET THIN (AND HEALTHY) The Medical Consequences of High-Protein Low-Carbohydrate Diets

Dr Magda Robinson, BM

Dr Magda Robinson, BM was born in Oxford, UK, and studied psychology at university, followed by a degree in medicine. After qualifying as a doctor, she began her career as a GP, and subsequently developed a keen interest in nutrition. She has been practising as an obesity management consultant in London, UK for 18 years. She specialises in using nutrition to aid weight loss and to combat cardiovascular disease, diabetes and cancer. She is a member of the Association for the Study of Obesity, and the National Obesity Forum.

CONTENTS INTRODUCTION

1. THE FLAWED THEORIES BEHIND HIGH-PROTEIN LOW-CARBOHYDRATE DIETS

2. THE EFFICACY OF DIFFERENT WEIGHT LOSS DIETS Intervention studies on HPLC diets Observational population studies on weight Childhood patterns of protein intake and subsequent obesity Factors which are known to influence the efficacy of diets Satiety Satiety hormones Glycaemic index and glycaemic load Insulin score Energy density Enhanced satiety of Quorn (mycoprotein) Enhanced satiety of potatoes Thermic effect of food

12 13 18 20 20 20 21 24 24 27 29 30 30

3. THE SHORT-TERM SIDE EFFECTS OF HIGH-PROTEIN LOW-CARBOHYDRATE DIETS Sudden cardiac death Commercial HPLC diet warnings on side effects Nutritional deficiencies Thiamine deficiency Folate deficiency What is the minimum amount of carbohydrate needed? Loss of muscle mass Metabolic acidosis Hypothyroidism Mental function Serotonin metabolism Pregnancy and mental function What is the maximum safe level of dietary protein? Gout Individual case studies

PART 2: THE LONG-TERM SIDE EFFECTS OF HIGH-PROTEIN LOW-CARBOHYDRATE DIETS

4. CARDIOMETABOLIC RISK Dietary fat Current medical guidelines on fat consumption What are the typical fat contents of HPLC diets?

49 50 50 51

33 35 36 38 38 39 39 40 41 42 43 44 45 46 47

Case study of an HPLC diet associated with angina Saturated fat Epidemiology and cardiometabolic risk factors Case study: Bill Clinton Mechanisms of saturated fat-mediated damage Saturated fat-mediated inflammation and insulin resistance Lipotoxicity Trans fats Arachidonic acid Polyunsaturated/monosaturated fat to saturated fat ratio Omega 6 to omega 3 ratio Cholesterol Fat and protein content of foods compared Dietary fibre Fibre and cardiometabolic risk: cholesterol Fibre and cardiometabolic risk: insulin resistance and diabetes Meat and milk and type 2 diabetes Glycaemic index and diabetes risk Treating insulin resistance through diet and glycaemic control Complications of diabetes and diet: diabetic neuropathy and renal function Advanced glycation end-products (AGEs) AGE content of sample foods Vascular effects of low-carbohydrate diets Hypertension and diet Uric acid Other nutrients influencing cardiometabolic risk

55 55 56 60 61 61 65 66 66 67 68 68 69 70 70 72 73 76 78 81 84 85 87 89 90 91

5. CANCER Cancer-promoting agents Effect of protein on tumour development Carcinogens found in dairy foods: insulin-like growth factor 1 (IGF-1) Hyperinsulinaemia Carcinogens found in meat, fish and poultry Heterocyclic amines Polycyclic aromatic hydrocarbons N-nitroso compounds Haem iron Saturated fat and arachidonic acid Global research studies and world health advisory body recommendations Cancer-fighting phytochemicals Bowel cancer Fibre's protective effect for bowel cancer Breast cancer Ovarian cancer Prostate cancer Lung cancer

93 93 93 95 97 97 98 99 99 100 101 102 107 109 112 115 117 117 119

6. RENAL FUNCTION Renal stones and osteoporosis

120 121

7. BOWEL FUNCTION Constipation Lactose intolerance and allergy Autoimmune disease, intestinal microflora and leaky gut Short-chain fatty acids Prebiotics and probiotics in relation to weight Metabolic actions of endotoxin producing bacteria Antidiabetic actions of prebiotics Fatty liver and cholesterol Irritable bowel syndrome

127 127 127 127 134 134 136 137 138 139

8. MENTAL FUNCTION Alzheimer's disease and cognitive function Parkinson's disease

140 140 143

9. IRON IMBALANCE Haem iron toxicity

144 145

10. PROTEIN Plant-based protein Benefits of plant-based protein Protein content of foods compared Protein quality Fish Soya Phytoestrogens Soya and cancer Soya and mental function Soya and thyroid function Soya and digestion Soya and aluminium Soya and cardiovascular disease Soya and bone density Soya's nutritional quality

147 147 147 149 150 152 154 154 155 158 159 159 160 161 162 162

11. WORLD HEALTH ADVISORY BODIES' STATEMENTS ON HPLC DIETS 164 Association for the Study of Obesity (ASO) 164 American Heart Association (AHA) 164 Physicians Committee for Responsible Medicine (PCRM) 168 US Department of Agriculture, US Department of Health and Human Services 169 National Heart Foundation of Australia 170 British Dietetic Association 171

Food Standards Agency Heart and Stroke Foundation of Canada American Dietetic Association American Cancer Society Physicians' Guide to Popular Weight Loss Diets Low-Carbohydrate High-Protein Diets. Is There a Place for Them in Cinical Cardiology?

172 173 173 174 174 175

12. MORTALITY AND HPLC DIETS: ARE THERE EFFECTIVE HEALTHY ALTERNATIVES? Ageing and chronic disease Ageing, caloric restriction and protein restriction Overall mortality of low-carbohydrate diets Life expectancy and diet Healthy alternatives to HPLC diets

177

13. WORLD HEALTH ADVISORY BODIESâ&#x20AC;&#x2122; STATEMENTS ON PLANT-BASED DIETS British Medical Association (BMA) World Health Organisation (WHO) Heart and Stroke Foundation European Prospective Investigation into Cancer and Nutrition (EPIC) Study Physicians Committee for Responsible Medicine US Department of Health and Human Services American Diabetes Association American Cancer Society American Dietetic Association

187

177 177 179 181 182

187 187 189 189 189 190 191 192 192

14. OTHER RECOMMENDATIONS FOR HPLC DIETS AND CONCLUSION 193 Conclusion 194 PART 3: A HEALTHY AND EFFECTIVE DIET FOR WEIGHT LOSS

196

15. THE 5:15 DIET

196

16. THE 5:15 DIET MEALS

200

17. REAL LIFE DIET CASE STUDIES

207

18. FURTHER READING

211

REFERENCES

212

INTRODUCTION This book was prompted by my wish, as a medical doctor who has been specialising in the treatment of obesity for 17 years, to assess how high-protein low-carbohydrate (HPLC) diets affect patients’ health. These diets, which consist of less than 40% carbohydrate and at least 30% protein, typified by the Atkins Diet, South Beach Diet, and Dukan Diet, are being widely promoted for weight loss in the media and in many commercial weight-loss programmes, but are they to be recommended? It is of utmost importance that I “do no harm” and that I prescribe weight-loss regimes that are both effective and healthy. In fact this famous quote from the Hippocratic Oath is taken from the sentence: “I will use those dietary regimens which will benefit my patients according to my greatest ability and judgement, and I will do no harm or injustice to them.” (Hippocratic Oath). I wanted to compare these diets with other weight-loss diets, to find out which were the most beneficial in terms of health. In doing so I have used a variety of resources, including my own clinical experience. I have conducted a lot of research and attended many medical conferences over the years on the subject of diet, obesity, and health, and decided that I would summarise some of what I have learned. I am going to examine the scientific validity of HPLC diets, and their short- and longterm side effects, looking at the biochemistry and physiology and evidence from clinical trials. My basic argument is that overloading the body with protein is unhealthy, not only because it is detrimental to liver and renal function, but also because unless the diet is low in saturated fat, low in animal protein, and high in fibre, it can lead to a whole host of medical complications in the short and long terms. This should make us question the promotion of current HPLC diets, high in both saturated fat and animal protein. Furthermore, none of the world health regulatory bodies has endorsed high-protein lowcarbohydrate diets. What does the National Centre for Clinical Excellence (NICE) recommend as a diet for weight loss, in its guidelines on obesity? "- Base meals on starchy foods such as potatoes, bread, rice and pasta, choosing whole grain where possible. - Eat plenty of fibre-rich foods - such as oats, beans, peas, lentils, grains, seeds, fruit and vegetables, as well as whole grain bread, and brown rice and pasta. - Eat at least five portions of a variety of fruit and vegetables each day, in place of foods higher in fat and calories. - Eat a low-fat diet and avoid increasing your fat and/or calorie intake. - Eat as little as possible of: - fried foods - drinks and confectionery high in added sugars - other food and drinks high in fat and sugar, such as some take-away fast foods. - Eat breakfast. - Watch the portion size of meals and snacks, and how often you are eating. - For adults, minimise the calories you take in from alcohol... Weight loss programmes are recommended only if they: 7

- are based on a balanced healthy diet - expect people to lose no more than 0.5-1 kg a week Programmes that do not meet these criteria are unlikely to help people maintain a healthy weight in the long term.â&#x20AC;? (NICE 2006). The above guidelines, which are intended for all health professionals, bear no resemblance to HPLC diets. I will now outline why the NICE guidelines are correct, and any HPLC diet is ill-advised in both the short term and the long term.

1. THE FLAWED THEORIES BEHIND HIGH-PROTEIN LOW CARBOHYDRATE DIETS The theory behind HPLC diets centres on the principles of blood sugar, insulin, the process of “fat burning”, and ketosis. According to this theory, depriving the body of carbohydrates forces the body to use up its fat stores to provide energy, as in the process of fasting. Allegedly, an HPLC diet causes insulin levels to fall, and as insulin is a “fatstoring” hormone, and switches off “fat burning”, the net result is fat loss. The byproducts of this fat burning are ketones, organic acids formed when fatty acids are partially oxidised in the liver. Ketosis can be measured using dipsticks in the urine, as well as being smelt on the breath. Subjects are led to believe that going into ketosis is the only way to burn fat. Unfortunately this theory is flawed in many ways, with incorrect biochemistry and anecdotal “evidence”, which after critical analysis has been found to be in error. A review in Obesity Research stated “The studies by Atkins to support his contentions were of limited duration, conducted on a small number of people, lacked adequate controls and used ill-defined diets” (Freedman et al. 2001). It also stated “In all cases, individuals on high-fat, low-carbohydrate diets lose weight because they consume fewer calories… no magic ingredients, strange food combinations or pseudoscientific formulas will alter this metabolic fact.” A medical analysis of the South Beach Diet stated that it is “based on fallacies… replete with faulty science, glaring nutritional inaccuracies, contradictions, and claims of scientific evidence minus the actual evidence.” (Schipani 2004) The main criticisms of the HPLC theory are summarised here, and will be discussed in greater depth later. 1. HPLC diets contain excessive amounts of protein and fat. Protein cannot be stored in the body, so excess protein is converted into glucose for fuel and fat for storage: one might as well have eaten the banned carbohydrate food in the first place. Excess fat and protein is therefore undesirable, as there is unlimited capacity to store fat in adipose tissue. 2. Without carbohydrates, the body's own muscles are broken down to provide substrates for the formation of glucose via the process of gluconeogenesis, in order to feed glucosedependent tissues such as the brain, neurons, red blood cells, testes and renal cortex cells. Dietary carbohydrate at a minimum of 130 g a day is necessary for its “protein sparing action”. Loss of muscle tissue is the exact opposite of any dieter's aims. 3. Numerous studies have shown that HPLC diets are no more successful than any other calorie-reduced diet at one year. Initial seemingly rapid weight loss is mainly due to the loss of water, which is regained once the diet is stopped. On analysis, successful HPLC dieters have lost weight only if they have reduced caloric intake, just like any other diet. The diets are so restrictive, monotonous, and limited in food choices that reduced caloric intake is almost inevitable. There is nothing “magic” about them.

4. The body requires a lot less protein (0.8 g/kg/day), than is commonly perceived. For example a 60 kg woman requires only 48 g a day. A 70 kg man requires only 56 g a day. Protein intake above the minimum required does not result in increased muscle mass or strength, so long as energy balance is achieved: exercise is the determinant of muscle mass. Even at low levels of intake (0.57 g/kg/day), body protein is maintained if there is daily physical exercise at neutral energy balance. The response of protein turnover to exercise is independent of dietary protein intake (0.9 or 2.5 g/kg/day) from isoenergetic diets (Metges & Barth 2000). It is relatively easy to achieve adequate amounts of protein, even on a calorie reduced diet, if overall 20% of the diet is protein. For example on 1000 calories a day, 50 g of protein is required, equal to 200 calories (20% of the calories). On a weight maintenance diet of 2000 calories a day, 50 g of protein is equal to 10% of the calories. There is protein in all foods apart from pure oils and pure sugars. Broccoli contains 45% protein. Bread contains 19% protein. Even oranges and raspberries contain 10% protein. 5. Glucose is not the only trigger for the release of insulin: certain amino acids (e.g. arginine, leucine, isoleucine, valine and lysine, to name but a few) are potent stimulators of the insulin response (insulinotropic). Later on, I will discuss how protein foods such as beef and milk products cause a greater insulin response than pasta, or porridge, despite having a lower glycaemic index. Thus a high-protein diet can actually result in raised insulin levels: the opposite of the desired result. Furthermore, most HPLC diets ban fruit, which is unnecessary because the glycaemic index of fructose is only 19, and also fructose does not stimulate insulin secretion: the beta pancreatic cells have very low levels of the fructose transporter glucose transporter 5 (Sato et al. 1996). 6. Fatty acids are also known to be insulinotropic, particularly the saturated variety. The more saturated the fatty acid, the greater the glucose-stimulated insulin secretion (McGarry & Dobbins 1999). Thus stearate, abundant in animal fat, causes more than three times as much insulin output than the vegetable fat linoleate: the beta cell of the pancreas becomes hypersensitive. Added to this factor, accumulation of fat in muscle cells causes impaired insulin-mediated glucose uptake, i.e. insulin resistance. Indeed, lipid infusion for 48 hours in normal humans induces insulin resistance and chronic hyperglycaemia, accompanied by hypersecretion of insulin. The net effect is that diets high in saturated fat cause a high ratio of saturated to unsaturated fatty acids in the blood, and this contributes to hyperinsulinaemia, dyslipidaemia, and insulin resistance: characteristics of the early stages of type 2 diabetes. In the long term, saturated fatty acids have a lipotoxic effect on the beta cells of the pancreas, causing beta cell dysfunction and impaired insulin synthesis, worsening the diabetic state. As HPLC diets are generally high in saturated fat, the accumulation of lipid in both the muscle and pancreatic cells can lead to insulin resistance and progression to diabetes. 7. Ketone bodies, the toxic by-products of a low-carbohydrate diet, are not desirable as they are associated with many detrimental side effects. These include fatigue, nausea, dehydration, and loss of electrolytes. In addition, ketosis is associated with a depletion of insulin receptors, thus reducing insulin sensitivity and contributing further to saturated fatty acid-induced insulin resistance. Ketones also generate oxygen radicals and cause lipid peroxidation, playing a role in cardiovascular disease and diabetes (Laffel 1999). 10

One of the most serious side effects of ketosis is metabolic acidosis, which can be fatal if left unchecked, as in diabetes. 8. It is not essential to go into ketosis to burn fat. Adipocytes (fat cells) undergo lipolysis throughout the day and night (e.g. in between meals and overnight, during exercise, during episodes of stress, or feeling cold). Adipocytes release fatty acids which are oxidised in the mitochondria of the body’s cells (e.g. muscle cells) to produce acetylcoenzyme A (beta-oxidation). The acetyl-coA then enters the Kreb’s Cycle for energy production. Ketosis only happens in the liver if there is excess acetyl-CoA (e.g. in excessive lipolysis), thus saturating the Kreb’s Cycle enzymes, or if the Kreb’s Cycle intermediates (e.g. oxaloacetate) are depleted, due to their utilisation in gluconeogenesis (the formation of glucose from amino acids). The latter process occurs if less than 100 g of carbohydrate is consumed a day, and amino acids are utilised for the formation of glucose. This excess acetyl-CoA is then converted into ketone bodies in the liver. Thus ketosis can occur with lipolysis, but is not essential. There is no advantage in terms of weight loss if the body is in ketosis; it merely illustrates that fat is being oxidised incompletely, due to the absence of carbohydrates. The presence of carbohydrates is far preferable, as fat is oxidised completely without any toxic byproducts. Eliminating ketones via the kidneys causes loss of both water and sodium, resulting in false “weight loss” and dehydration, and elimination via the breath causes offensive halitosis. 9. It is undesirable to aim for minimal insulin release, as insulin is the only anabolic hormone (it builds up muscle tissue). Individuals wishing to lose fat while keeping or improving their muscle mass, need insulin to enhance protein uptake into the muscles, stimulate protein synthesis and inhibit proteolysis (protein degradation). Furthermore, insulin is a known satiety agent. 10. In an extensive review of the glycaemic index and insulin, the notion that insulin causes weight gain (as proposed by HPLC diets) is challenged: an important role for insulin in terms of body weight is that at physiological levels it reduces food intake (PiSunyer 2002). Only at large doses, enough to cause actual hypoglycaemia (seen, for example, in any case of over-treatment of type 1 diabetes), can the net result be a stimulation of food intake. This review goes on to say that there is no evidence to support the claim that at physiological concentrations insulin triggers weight gain. In fact, increased insulin secretion actually protects against substantial weight gain. It has also been noted to decrease food intake when injected straight into the brain, provided that a low-carbohydrate high-fat diet is not being followed, as this induces insulin resistance (Clegg et al. 2011). 11. HPLC diets are seriously deficient in many different vitamins, minerals, and fibre (the Atkins diet demands that 63 different vitamin, mineral, and fibre supplements are taken to make up for the shortfall), while supplying atherogenic amounts of saturated fat and cholesterol. 12. HPLC diets have numerous serious side effects, both long- and short-term.

2. THE EFFICACY OF DIFFERENT WEIGHT LOSS DIETS The risk of cardiovascular disease is reduced if a healthy BMI is maintained. Medical opinion advises all overweight and obese individuals to lose weight, as this leads to a decrease in the factors which make up metabolic syndrome: the presence of abdominal obesity, hypertension, insulin resistance, atherogenic dyslipidaemia, inflammation, and a pro-thombotic state. All these factors increase the risk of cardiovascular disease. The question is, what is the best way to lose weight? The dietary method must be both effective and safe. HPLC diets can produce weight loss, provided that the calorie intake is less than calorie expenditure. However the method is not safe due to causing an increase in low density lipoprotein (LDL) cholesterol and all the other numerous reasons to be outlined later, unless plant proteins are substituted for animal proteins. Furthermore, research has indicated that the HPLC method is not even particularly effective, as initially the weight loss is mostly water due to a depletion in glycogen stores, and diuresis due to the need to expel ketones. It is also not usually maintained long term. In the first 2 weeks on an HPLC diet most of the weight loss is fluid and glycogen. There are 100 g of glycogen stored in the liver, and 400 g of glycogen stored in the muscles. Each gram of glycogen is bound by 3 g of water, so utilization of glycogen stores alone results in a weight loss of 2 kg. Added to this mechanism is that any reduction in insulin, which causes sodium retention by the kidney, will also promote fluid loss due to increased excretion of sodium. If glucagon rises, this too will lead to loss of water, as it is a natural diuretic. Induction of ketosis occurs at a level of 50 to 100 g of carbohydrate a day, so increased excretion of ketones via the kidney will result in extra potassium and sodium loss, together with water. It is only once a new mineral balance is achieved that weight loss is dependent on the energy deficit, leading to the release of fatty acids from the fat stores, just like any other low calorie diet. A systematic review of low-carbohydrate diets examined 107 studies, and found that the carbohydrate content was not correlated with the amount of weight loss. Calorie intake and the duration of the diet was the main determinant of body weight (Bravata et al. 2003). Another extensive review of low-carbohydrate diets stated: â&#x20AC;&#x153;All hypoenergetic diets result in loss of body weight and body fat. Losses of protein and fat are the same during a ketogenic diet as during a hypoenergetic non-ketogenic diet. Hence no diet is superior to another in terms of preservation of lean body mass. However, low-carbohydrate diets are at greater risk of being nutritionally inadequate... typically, low-carbohydrate diets are low in fibre, thiamine, folate, vitamins A, E, B6, calcium, magnesium, iron, and potassium in the absence of supplemental multivitamins. There is a real risk of nutritional deficiency occurring... Energy restriction, irrespective of dietary composition, promotes weight loss and improvement of glycaemic control.â&#x20AC;? (Bilborough & Crowe 2003).

Intervention studies on HPLC diets An example of the considerable diuretic effect of ketotic diets is an experiment conducted in a hospital where the diet was strictly controlled: one group of patients fasted completely, one group ate a low-carbohydrate, high-fat ketotic diet, and another group ate a nonketotic mixed diet but the same number of calories (Yang & Van Hallie 1976). The trial lasted for 10 days, and there was minimal exercise as the patients were confined to hospital. The meals of 200 kcal were delivered 4 times a day. Daily energy nitrogen balance studies were conducted on the patients to assess the composition of the weight loss. Table 2.1. The dietary composition and weight loss after one day of fasting, a lowcarbohydrate ketotic diet, and a nonketotic diet Protein (casein) Carbohydrate (sucrose) Fat (corn oil)

Fasting 0 0 0

Loss of water Loss of fat Loss of protein Total loss of weight 1 day Total loss of weight 10 days

456g/61% 243g/32% 50g/7% 749g 7.5kg

Low-carb ketotic diet 50g 10g 62g 286g/61% 163g/35% 18g/4% 467g 4.6kg

Nonketotic diet 50g 90g 27g 103g/37% 167g/60% 9g/3% 279g 2.8kg

We can see in Table 2.1 that although the ketotic diet resulted in greater weight loss than the nonketotic diet, the amount of water loss was nearly triple that of the nonketotic diet, and the amount of protein loss was double. Furthermore, slightly less fat was lost on the ketotic diet. Thus there was no nitrogen sparing on the ketotic diet. This experiment was for 10 days and highlights the initial â&#x20AC;&#x153;falseâ&#x20AC;? weight loss of a low-carbohydrate diet. Longer studies comparing diets of different carbohydrate levels but of equal calories have also been conducted, using similar tightly controlled methods in a hospital (Table 2.2) (Golay et al. 1996). Table 2.2. Composition of a low-carbohydrate ketotic diet and a low-carbohydrate nonketotic diet, both 1000 kcal, for 6 weeks Protein Carbohydrate Fat

Low-carb ketotic diet Low-carb nonketotic diet 79g 73g 37g 115g 60g 30g

The weight loss at 6 weeks was the same between the two diets. Thus there was no superiority in the ketotic diet, and the researchers found no correlation between ketosis and weight loss. Another human study on ketotic and isocaloric nonketotic diets (Table 2.3) found that weight loss was the same at 6 weeks, with a tendency for greater weight and fat loss with the nonketotic diet (Johnston et al. 2006). There was also an increase in LDL cholesterol, directly related to blood ketone concentrations. The authors concluded that extreme restriction of carbohydrates gives no metabolic advantage, but does illicit side effects and poor nutrition. Table 2.3. Dietary composition of a low-carbohydrate ketotic diet and a lowcarbohydrate nonketotic diet, both 1500 kcal, for 6 weeks Low-carb ketotic diet Low-carb nonketotic diet Calories 1500 1500 Protein 125g 117g Carbohydrate 33g 157g Fat 100g 50g Saturated fat 35g 13g Cholesterol 620mg 230mg As well as the unfavourable amounts of saturated fat and cholesterol, the ketotic diet had much lower levels of fibre, vitamin A, thiamine, folate, riboflavin, vitamin B6, vitamin C, vitamin E, calcium and iron than the nonketotic diet. In fact the levels of fibre, folate, vitamin E, iron, magnesium and potassium were less than 67% of recommended dietary intakes with the very low-carbohydrate diet. Blood samples revealed that risk factors for atherosclerosis were higher in the ketotic group: LDL cholesterol was directly correlated with ketone level, with several of the participants suffering from a marked increase. The ratio of arachidonic acid to the omega 3 fatty acid eicosapentaenoic acid (EPA) in serum phospholipids was 90% higher in the ketotic group, indicating a greater level of inflammation. This has the potential to fuel metabolic syndrome, atherosclerosis and tumour initiation and growth (to be discussed later). There were also deleterious changes in markers of kidney health in the ketotic group: creatine clearance increased by 20% in the second week of the ketotic diet, indicating a sign of kidney hyperfiltration. This can lead to glomerulosclerosis (scarring in the kidneys) in individuals with compromised renal function (approximately 11% of the general population and 30-40% of diabetics), further reducing kidney function. There was no difference in hunger ratings between the ketotic and nonketotic group, contrary to popular notions of ketosis suppressing the appetite. Also the ketotic group had lower energy levels and lower mood scores that the nonketotic group. Similar findings have also been found in rats on reduced calorie isocaloric diets (Table 2.4) (Beck & Richy 2009).

Table 2.4. Dietary composition of a low-carbohydrate, high-fat diet and a highcarbohydrate, low-fat diet: a rat study Low-carbohydrate, high-fat Protein % 18 Carbohydrate % 32 Fat % 50

High-carbohydrate, low-fat 20 64 16

Both groups of rats lost the same amount of weight and body fat after 3 weeks of the diets, underlining the importance of caloric restriction as opposed to macronutrient composition for weight loss. As an aside, both groups also gradually regained the weight that they had lost and were back up to their starting weights after 3 weeks of refeeding: levels of the â&#x20AC;&#x153;hunger hormoneâ&#x20AC;? increased and caused the rats to eat larger meals. This emphasizes the need for long-term careful eating for weight maintenance. Looking at even longer comparative diet studies, a one year randomised trial compared popular weight-loss diets and reported that the highest reductions in BMI were on the Ornish diet (low-fat/high-carbohydrate), followed by Weight Watchers (calorie restriction), the Zone (macronutrient balance) and the Atkins diet (HPLC), in those participants who completed dieting to one year (Table 2.5) (Dansinger et al. 2005). Table 2.5. BMI reductions on the Ornish, Weight Watchers, Zone and Atkins diets, at one year 2months 12 months

Ornish Weight Watchers Zone -1.7 -1.5 -1.6 -2.3 -1.7 -1.6

Atkins -1.6 -1.4

Note that the Ornish diet (only 10% fat) was the most successful diet at 2 months and 12 months, with continued weight loss, while the Atkins dieters actually started to gain weight after initial weight loss. The Ornish dieters also had considerably lower cholesterol and LDL cholesterol levels throughout the study, compared with the other dieters. Furthermore, the Atkins dieters were the only group not to show any significant reductions in insulin levels at one year. As one of the main aims of HPLC diets is, according to the theory, to reduce insulin levels, this result is the opposite of what was intended. Another one year randomized controlled trial was conducted by the American cardiologist Dr Richard Fleming, who compared the weight loss and cardiovascular disease risk factors of several different calorie reduced diets (less than 1600 kcal): an HPLC diet (25-30% protein), and 3 normal protein diets (15% protein), consisting of the Fleming Phase 1 high-carbohydrate, low-fat diet (FP1); the Fleming Phase 2 caloriecontrolled, high-carbohydrate, moderate-fat diet (FP2); and a control group of a high-

carbohydrate, moderate-fat diet, which was similar to a typical Western diet of 2000 to 2200 kcal (Table 2.6) (Fleming 2002). The low-fat and the HPLC dieters were allowed to eat until satiated, but spontaneously ate a reduced calorie diet. Table 2.6. Dietary composition of a typical US diet, a high-fat HPLC diet, a moderate-fat diet, a moderate-fat calorie controlled Fleming Phase 2 diet, and a lowfat Fleming Phase 1 diet Diet Typical US diet

Kcal/day 2200

Fat g/%kcal Carb g/%kcal 85g 35% 275g 50%

Protein g %kcal 82 g 15%

High-fat (HPLC)

1400-1500

97g 55-65%

36g

100g 25-30%

Moderate-fat (control) 2000-2200

58g 20-30%

315g 60%

79g

15%

Moderate-fat (FP2)

1500-1600

26g 15%

271g 70%

58g

15%

Low-fat (FP1)

1300-1400

15g 10%

253g 75%

51g

15%

10%

All the dieters lost weight apart from the control group, but there were striking differences in the degree of weight loss and changes in cardiovascular disease risk factors (Table 2.7). Table 2.7. Outcomes at 12 months of a low-fat Fleming Phase 1 diet, a moderate-fat calorie controlled Fleming Phase 2 diet, and a high-fat HPLC diet Low-fat high-carb (Fleming Phase 1) Weight loss % -18.4% Weight loss kg -23.6kg Cholesterol -39.1% LDL cholesterol -52% Triglycerides -37.3% HDLC +9% Total chol/HDLC ratio -45.8% Homocysteine -7.4%

Mod-fat cal controlled (Fleming Phase 2) -12.6% -13.2kg -30.4% -38.8% -36.9% +3.6% -34.7% -10.8%

HPLC (high-fat) -13.7% -14.5kg +4.3% +6% (+5.5% not stat sig) -5.8% +9.8% +3%

Here we can see that the percentage weight loss was 25% greater in the low-fat, highcarbohydrate group than the HPLC group. Furthermore, there were dramatically beneficial changes in cardiovascular disease risk factors in the low-fat, high-carbohydrate group compared with the HPLC diet, which had a worsening in cardiovascular disease risk factors (in italics), despite the weight loss. The moderate-fat group had intermediate results (all beneficial). For example, homocysteine is an amino acid, which when raised in the blood is associated with an increased risk of atherosclerotic cardiovascular disease and cancer. It is associated with high inflammation and high oxidative stress. The author commented on the detrimental increases in homocysteine levels in the HPLC group,

explaining this could be a result of eating excess animal protein, and reduced levels of folic acid or vitamin B6. A description of the Phase 1 and 2 diets is found in Dr Fleming's books Stop Inflammation Now (2005) and The Healthy Heart Programme (2004). The low-fat diet (Fleming Phase 1) consists of 2 servings of whole grains or cereals in the morning, plus 13 servings of fruit, 18 (minimum) servings of vegetables (at least 8 green vegetables; at least 8 yellow, orange and red vegetables; at least 1 white vegetable; at least 1 root vegetable, at least 1 serving of potatoes, and 4 to 7 servings of pulses (peas, beans, lentils, soya products such as tofu) consumed as meals and snacks throughout the day. One teaspoon of flaxseeds was allowed per day, and 3 teaspoons of pumpkin seeds were allowed per week. The emphasis is on variety with as many different types of plant food as possible. This is designed to rapidly reduce inflammation in the body in order to reverse cardiovascular disease and to reduce the inflammatory factors linked with the development of chronic degenerative diseases such as diabetes, arthritis, Parkinson's disease, Alzheimer's disease and cancer. It is essentially a vegan diet. The moderate-fat dieters (Fleming Phase 2 diet) were told to eat complex carbohydrate rather than simple sugars, and mostly non-saturated fat (a maximum of 5 g of saturated fat a day). This is a long-term maintenance anti-inflammatory diet with more modest outcomes than Fleming Phase 1, but more flexibility. They ate the fruit, vegetables and seeds of the low-fat group, plus almonds and walnuts. Other foods included 3 servings a week of low-fat dairy products, and 2 eggs a week. If any flesh foods were eaten they had to be within the 5 g of saturated fat allowance, portions no bigger than 50 g and a maximum of 6 times a week. Consumer surveys have also found inferior outcomes with HPLC diets. For example one survey of 1329 adults reported that low-carbohydrate diets were 50% less effective at helping people lose weight than weight-loss diets in general (Hartman Group 2004): only 14% of individuals reached their target weight on HPLC diets, compared with 29% reaching their target weight on conventional diets. A randomized controlled trial over one year comparing an HPLC diet (less than 20 g of carbohydrate a day) with a conventional â&#x20AC;&#x153;low-calorie, low-fat, high-carbohydrateâ&#x20AC;? diet (1500 kcal, 25% fat, 15% protein, 60% carbohydrate), found that although the weight loss was greater at 3 months with the HPLC diet, there was considerable weight regain after 6 months on the diet. (35% of the weight loss on the HPLC diet was regained at 12 months, compared with only 7% of the weight loss on the conventional diet being regained at 12 months). The net result was no significant difference in weight loss between the two diet groups at 12 months (Foster et al. 2003). Note that the macronutrient composition of the conventional diet was 42 g of fat, 56 g of protein and 225 g of carbohydrate a day, so Dr Fleming would call this a moderate not a low-fat diet. Had the diet been a true low-fat diet of less than 20 g of fat a day, the results may have indicated superior weight loss compared with the HPLC diet. Interestingly it was reported that there was no significant relation between weight loss and ketosis at any time in the study.

Other studies have mirrored the above results, showing that HPLC diets cause statistically significant weight loss, but that at 12 months the weight loss is no different from conventional “low-fat” calorie restricted diets (Astrup et al. 2004). A meta-analysis of five randomized controlled trials revealed that the weight loss at 12 months was similar between HPLC diets (carbohydrate less than 60 g a day), and “low-fat” calorie restricted diets (less than 30% fat). Thus the HPLC diets were not more effective. In addition, detrimental effects were again seen in HPLC dieters, with total cholesterol and LDL cholesterol being consistently raised in the HPLC dieters (Nordmann et al. 2006). Thus if the weight loss is going to be the same whatever the macronutrient composition, and cardiac risk factors only increase with one of the methods (the HPLC diet), it is advisable to opt for a non-HPLC method (lower fat, higher carbohydrate). Again, the definition of “low-fat”, at less than 30% fat, would still be considered a moderate-fat diet by Dr Fleming. Had the control diets been stricter in fat intake as in the Fleming study, the results may have indicated more success with the truly low-fat diet. Observational population studies on weight On the question of weight loss maintenance, a good resource is the National Weight Control Registry (NWCR). To be eligible, participants must have lost a minimum of 14 kg, and have kept it off for at least one year. On average, the weight loss is actually 30 kg, and has been maintained for 5 years 6 months. A study conducted an analysis of the successful weight maintenance strategies and revealed some common themes: the eating of breakfast; weighing oneself once a week; exercising for one hour a day at moderate intensity or 400 calories a day in physical expenditure (e.g. brisk walking); and a calorie intake of 1381 calories a day (Wing and Hill 2001). Note that dietary intake is frequently under-reported by about 20-30%, so it is likely that the calorie intake was nearer 1800 calories. The average nutrient composition was: 56% carbohydrate, 19% protein and 24% fat i.e. successful weight loss maintenance was based on a low-calorie, low-fat, normal-protein, and normal-carbohydrate eating. A typical breakfast was cereal and fruit: the opposite of an HPLC breakfast! Indeed, less than 1% of the participants reported being on an HPLC programme (less than 24% of carbohydrate a day, or less than 90 g of carbohydrate on 1500 calories a day). Furthermore, those on an HPLC programme had maintained their weight loss for a shorter amount of time and were less physically active (confirming that HPLC diets reduce energy levels). Other variables documented were that on average the successful weight maintainers ate fast food only 0.74 times a week, and ate out in restaurants 2.5 times a week. Eating frequency was 4.87 times a day, indicating that eating small frequent meals is better than eating larger fewer meals. A later analysis of the National Weight Control Registry dieters found a greater proportion following HPLC diets, but still only 10.8% of the registry (Phelan et al. 2007). The reason for this increase could have been a new link to the NWCR website from the Atkins website during this study period. There were some alarming statistics on the average saturated fat intake of the HPLC dieters: it was 24% of the daily calorie intake.

As the average calorie intake for this group was 1894 kcal a day, this represents an astonishing 50 g a day of saturated fat (250% of the recommended maximum of 20 g a day). The authors stated “The greater intake of saturated fat in low-carbohydrate dieters is of great concern given the association between saturated fat intake and increased plasma concentrations of lipids, insulin resistance and coronary artery disease.” One cross-sectional analysis of existing dietary habits found that the lower the carbohydrate intake the higher the rate of obesity, and the higher the carbohydrate intake the lower the rate of being overweight or obese (Merchant 2009). In fact the lowest risk (by 42%) was obtained by consuming 290 to 310 g/day carbohydrates. This is equivalent to 1200 kcal a day of carbohydrate, or 23 slices of bread! The study controlled for total energy intake, age, exercise, sex, smoking, education and income, so can only be explained by nutritional intake alone. Another study found that BMI was positively associated with the type of carbohydrate only (causing a rapid rise in glycaemia), and not with percentage energy from carbohydrate or the amount of carbohydrate (Ma et al. 2005). Thus the answer to weight loss is not to reduce carbohydrate but to replace refined carbohydrates with whole grains. The observed advantage of a higher carbohydrate intake in terms of preventing obesity may have something to do with the fibre content of complex carbohydrate foods: in young adults, low fibre consumption predicts higher 10 year weight gain, waist-to-hip ratio and 2 hour post-glucose insulin levels (a measure of insulin resistance) to a greater extent than does total or saturated fat consumption (Ludwig et al. 1999). Raw and partially gelatinised starches (in legumes, whole grains and pasta) are more slowly digested than highly processed breads and breakfast cereals, which contain fully gelatinised starches. The fibre slows down carbohydrate absorption, making it more likely that food substrate will reach the lower part of the ileum to trigger the release of satiety hormones such as glucagon like peptide-1 (GLP-1) (de Graaf et al. 2004). Interestingly, a high-protein intake may actually back-fire when it comes to losing weight: it is frequently reported that there is a strong positive correlation between BMI and both fat and protein consumption. For example, one study reported that in the total population, a high-protein intake was associated with a higher percentage body fat (Vinknes et al. 2011). In the subgroup of the population who had a stable and intermediate BMI, fat intake was also associated with percentage body fat. Conversely in this subgroup, carbohydrate intake was inversely associated with body fat. Another study on 28,700 adults, based on a 500-question survey, found that increasing the amount of fat consumed was associated with an increased BMI, whereas the amount of ingested carbohydrate did not correlate with BMI (Benchetrit et al. 2004). The authors stated: “Low- or no- carbohydrate diets can consequently become high in fat and lead to weight gain in the long term.” This study was commented on by the vice-president of the American Obesity Association, Judith S Stern, ScD, RD, professor of nutrition and internal medicine at the University of California: “When you look at people who keep weight off, they pick a low-fat diet.”

One of the largest population studies ever conducted, on 373,803 subjects, found a strong association between meat intake (red meat, chicken and processed meat) and body weight gain (Vergnaud et al. 2010). BMI, exercise, total calorie intake and unhealthy dietary patterns were all controlled for, and the pattern was consistent in normal and overweight people. Thus an individual eating meat is more likely to gain weight than someone not eating meat, even if they eat the same number of calories. The average weight gain was 2.2 kg over 5 years, for each 250 g increase in meat consumption a day (equivalent to one steak of 450 kcal). The authors concluded that eating less meat would result in weight loss, because meat is an energy dense food with a high fat content. Another population study found that body weight gain was associated with consumption of red and processed meat. Conversely, weight gain was inversely associated with intake of vegetables, wholegrains, fruit and nuts (Mozaffarian et al. 2011). Childhood patterns of protein intake and subsequent obesity The effect of protein on body weight is particularly acute in childhood. The â&#x20AC;&#x153;early proteinâ&#x20AC;? hypothesis states that high-protein intakes in the first months of life increase the risk of subsequent obesity (Koletzko 2006). The theory is based on the observation that formula feed has a 50-80% higher protein content than human milk, and there is an increased risk of later obesity in non-breastfed children. Also during weaning and the transition to the family diet, there is a dramatic increase in protein intake, exceeding current recommendations by up to 5 times (Michaelsen et al. 2002). Thus a 12 month old child should be consuming 1.2 g/kg of body weight, an 18-24 month old 1 g/kg and a 3-6 year old child 0.9 g/kg of protein (Adults should have 0.83 g/kg). Exceeding these recommendations is associated with an increased BMI. For example, high-protein scores at 12, 18-24 months and 5-6 years are all associated with an increased BMI and body fat percentage at 7 years (Gunther et al. 2007a; 2007b). However this association is seen only with high intakes of animal and not vegetable protein, such as cereal protein. Dairy protein in particular has a strong association with later body fat percentage, whereas vegetable protein intake has an inverse relation. It is thought that dairy exerts its effects by inducing hormonal responses such as stimulating the secretion of insulin and increasing serum insulin-like growth factor-1 (IGF-1), which adversely affect preadipocyte differentiation and multiplication (Koletzko 2006; Rolland-Cachera 1995). Research on 2 and 8 year old children reveals that high intakes of milk increase insulin and insulin resistance, and serum IGF-1 (Hoppe et al. 2005, 2004a, 2004b). So we have evidence that an increased intake of animal protein in all stages of life, is associated with an increased BMI. Factors which are known to influence the efficacy of diets Satiety Any weight loss diet will only achieve weight loss if the calories are reduced. Highprotein diets have appealed in the past, partly because protein has been perceived as

having a strong satiety effect. Some also believe that ketones reduce hunger. However studies comparing HPLC ketotic diets with non-ketotic diets of similar calories have found comparable hunger ratings (Tsai & Wadden 2006). Furthermore, some carbohydrate containing foods have a higher satiety score than protein foods: potatoes have an even higher satiety score than protein per 100 calories, and are in fact the highest satiety-inducing food of all (Holt 1995). This would suggest that inclusion of one potato a day would have a beneficial effect on weight, comparable to taking an appetite suppressant. Apples are another carbohydrate food with a higher satiety score than beef, eggs or cheese (Holt 1995). The enhanced satiety effect of apples is illustrated in an experiment where significant reduction in overall calories and weight loss was achieved by adding one apple or pear 3 times a day to a weight-reducing diet , compared with eating oatcakes with the same amount of fibre (Oliveira & Moura 2003). In fact, a review of weight management studies concluded that increasing fruit and vegetable intake is an important strategy for weight loss (Rolls et al. 2004). Satiety hormones Different hormones/peptides involved in satiety are affected by differing degrees by various different macronutrients, as seen in Table 2.8 (Salmenkallio-Marttila et al. 2009): Table 2.8. The effect of different macronutrients on satiety hormones and peptides Peptide

Carbohydrate Fibre

Fat

Protein

Ghrelin

decrease

decrease/no effect/ inhibited or blunted decrease

decrease/no effect/ increase

decrease/ no effect/increase

Insulin

increase

blunted increase

increase

CCK

increase

GLP 1

increase

blunted increase/ no effect/increase

increase

PYY

increase

increase/no effect

increase

Amylin

increase

Pancreatic polypeptide

increase

no effect

increase

* means no studies undertaken

These hormones have different actions, with all but ghrelin in the above list acting by inhibiting food intake. Ghrelin Ghrelin is the only mammalian substance shown to increase appetite and food intake in humans. This is in contrast to numerous different satiety-related gastrointestinal peptides. An extensive review of the hormonal control of satiety reported that among different macronutrients, carbohydrates have been shown to be the most effective at suppressing postprandial ghrelin (the “hunger hormone”) concentration (Salmenkallio-Marttila et al. 2009). All of the reviewed studies showed a consistent suppression of ghrelin on ingestion of carbohydrates. However on examination of protein and fat ingestion, there were studies showing increased, decreased or no effect on ghrelin concentration, with no consensus. For example, one study examined the effects of eating (until satiated) fruit, vegetables, bread, fat combined with pork, and roast pork (Erdmann et al. 2004). The results showed that ghrelin was suppressed only with the fruit meals and the bread i.e. the highest carbohydrate meals. The levels were suppressed for 3 hours with the fruit, and 4 hours with the bread. Furthermore, bread had the lowest “hunger” score out of all the foods over the 4 hours. Soluble fibre (e.g. inulin) is a potent suppressor of ghrelin, in both rat and human studies (El Khoury et al. 2012). Sources of soluble fibre such as oats, barley, apples and pears are mostly absent on HPLC diets or not in sufficient quantities to have any biological effect. It seems that the type of protein dictates whether ghrelin is suppressed or not. For example gluten (from wheat), milk based proteins and soya protein cause prolonged suppression of ghrelin (Bowen et al. 2006). In contrast there is an actual increase in ghrelin after ingestion of meat protein (Erdmann 2006). Insulin Insulin causes a reduction in food intake, provided that there is no insulin resistance. For example, in an experiment in rabbits, insulin injected directly into the brain elicited a decrease in food consumption and body weight: insulin induces expression of the appetite suppressant genes POMC mRNA. However, this only occurred on a low-fat or normal chow diet (Clegg et al. 2011). Rabbits fed a high-fat diet did not respond to the anorectic effect of insulin, and this effect was associated with a reduced ability of insulin to activate its signaling cascade, and reduced expression of the POMC mRNA in the hypothalamus. The high-fat diet caused insulin resistance in the brain after only 3 days. Long term (70 days), this central insulin resistance was also evident in the high-fat diet rabbits, even when caloric intake and adiposity were controlled to match the low-fat diet rabbits. This experiment has direct implications for traditional HPLC diets high in fat,

indicating the production of central insulin resistance in the short and long term, and consequent negative effects on appetite and body weight. Cholecystekinin (CCK) CCK is produced in the brain, nervous system and upper small intestine, and causes reduced meal size and duration. It is interesting to note that although fat and protein induce greater postprandial concentrations than carbohydrates (Moran and Kinzig 2004), high-fat, low-carbohydrate feeding causes reduced CCK-induced satiety, possibly due to a down-regulation of vagal CCK1R receptors (Salmenkallio-Marttila et al. 2009). Thus, rats adapted to a high-fat diet exhibit reduced satiety in response to CCK: a lowcarbohydrate diet could backfire, causing reduced CCK sensitivity and hence increased meal size. It is well documented that fat is less satiating than carbohydrate or protein. Furthermore the type of fat is important in determining satiety. For example it has been shown that polyunsaturated fats are more satiating than saturated fatty acids (Lawton et al. 2000). Soluble fibre, found in oats, barley and beans and therefore lacking in HPLC diets, has been shown to cause greater and longer-lasting postprandial CCK levels in comparison to low-fibre meals (El Khoury et al. 2012). Glucagon-like peptide-1 (GLP-1) Glucagon-like peptide-1 (GLP-1) is released in the brain, distal small intestine and colon in response to food intake, in proportion to the energetic content of the meal. It acts by slowing the rate of gastric emptying and gut motility. Administration intravenously results in a dose-dependent reduction in food intake (Verdich 2001). Both carbohydrates and protein are potent stimuli for GLP-1, with fat also stimulating release. There are numerous appetite and gut hormones in the tongue taste buds including CCK and GLP-1. For example, during a meal, the presence of glucose on the tongue stimulates the sweet taste receptors which in turn causes the release of the satiety chemical GLP-1 within seconds. This explains the â&#x20AC;&#x153;needâ&#x20AC;? for dessert, and is a good argument for allowing one piece of fruit after every meal (as I recommend in my high-fibre, low-fat diet, to be discussed later). Once glucose reaches the small intestine, there are also sweet taste receptors in the L cells, which similarly respond through the stimulation of GLP-1, causing prolonged appetite suppression. There is an association between GLP-1 concentrations and the presence of probiotic bacteria in the gut. Fermentable carbohydrates such as inulin-type fructans, fed for 2 to 3 weeks, cause increased plasma concentrations of GLP-1 and precursor proglucagon mRNA concentrations in the proximal colon in both rats and humans (Cani et al. 2004; Delzenne et al. 2005; Cani et al. 2009). The relevance to HPLC diets is that they are lacking in fermentable carbohydrates and therefore do not optimise GLP-1 concentrations.

Peptide YY (PYY) Peptide YY (PYY) is released in the brain, small and large intestine, and acts by slowing gastric emptying and gut motility, thus increasing nutrient absorption. Its effect is to decrease appetite and food intake. Release is proportional to calorie intake, with carbohydrate, protein and fat all causing increased concentrations. Soluble fibre such as beta glucans, found in oats and barley, induces PYY release (Beck et al 2009). The mechanism is through short chain fatty acids (fermentation products) interacting with PYY cells: the main receptor for short chain fatty acids is colocalised with PYY L cells in the colon (Tazoe et al. 2008). Thus for maximal weight reduction via appetite control, a diet should aim to increase the source of fermentable soluble fibre (only found in carbohydrate containing food) such as resistant starch or pectin, to stimulate the release of PYY. It is clear that a mixture of macronutrients is important for release of the satiety-inducing hormones, and that a balanced approach rather than an HPLC approach is more sensible to ensure maximal release of all of them. Furthermore, in order to reduce ghrelin concentrations, it is important to use non-meat sources of protein. Glycaemic index (GI) and glycaemic load (GL) Slowing the absorption of nutrients from the intestine is desirable, as it results in a slow and steady increase in blood glucose levels, maintained over a long time. One feels fuller for longer. Different foods have different effects on blood sugar levels. The glycaemic index (GI) is the ratio of the measure of blood glucose levels found after eating 50 g of white bread or glucose, to a 50 g carbohydrate portion of test food (Jenkins et al. 1981). Low GI foods (GI less than 65) are those that cause low postprandial glucose responses, and include pasta, pumpernickel bread, legumes, nuts and parboiled rice. Medium GI foods (GI 65-89) include oats, All-bran and sweet potatoes. They reduce glucose absorption in the small intestine and the result is better glycaemic control. Low GI foods are usually good sources of fibre. The glycaemic load (GL) is the GI value multiplied by the amount of carbohydrate in grams and dividing the result by 100. This is a more accurate indicator of the value of a food, as certain â&#x20AC;&#x153;highâ&#x20AC;? GI foods such as watermelon with a GI of 80, actually have very low-carbohydrate levels (6 g per 100g), and hence a normal portion would produce only a modest rise in blood glucose (consuming watermelon until 50 g of carbohydrate was ingested would require eating 700 g!). The GL of watermelon is in fact only 5 for a 100g portion (Atkinson et al. 2008). Insulin score The problem with the glycaemic index is that it is not an accurate predictor of insulin response. It is well known that protein and fat rich foods also induce substantial insulin secretion, despite producing relatively small blood glucose responses. In fact the

glycaemic response is thought to account for only 23% of the variability in insulin response to food. (Pi-Sunyer 2002). Other factors include gastric emptying, gut hormone release, and the viscosity and the osmolality of the gut contents. Researchers developed an insulin score to address this problem: a ratio based on insulin levels found over 2 hours after consuming a 1000 kJ (240 kcal) meal of test food, to a 1000 kJ meal of white bread (Holt et al. 1997). A surprising result emerged: of the 38 foods tested, All Bran, porridge, white and brown pasta and peanuts all produced a lower insulin score than cheese, beef, fish and yogurt. In fact fish scored the same as apples, oranges, lentils, popcorn and crisps. Yogurt had a higher score than doughnuts, croissants, cake, crackers, cookies, all types of bread, rice and pasta and breakfast cereals! On average protein rich foods were markedly insulinogenic relative to their glycaemic effect, and stimulated a large amount of insulin secretion relative to their glycaemic response. Clearly protein rich foods are not insulin safe when compared with carbohydrate rich foods, as some protein rich foods induce as much or more insulin secretion as some carbohydrate rich foods. The figures in Table 2.9 are taken from the American Journal of Clinical Nutrition, which published the Insulin Index research (Holt et al. 1997). Table 2.9. Insulin score of different foods Insulin Score peanuts 20 eggs 31 All Bran 32 porridge 40 white/brown pasta 40 cheese 45 beef 51 popcorn 54 lentils 58 apples 59 fish 59 oranges 60 brown rice 62 cake 82 white bread 100 yogurt 115 skimmed milk* 142 whole milk* 148 *(Hoyt et al. 2005) Note the extremely high insulin index score for yogurt and milk, a discrepancy from the glycaemic indices which are not nearly as high: 42 for whole milk and 37 for skimmed milk (Hoyt et al. 2005). Indeed, other experiments have replicated these findings. For

example milk products were found to be more insulinotropic than bread, despite having a lower GI, with the essential amino acids leucine, valine, lysine and isoleucine being particularly implicated (Barclay 2004). As the GI of soya milk is only 36 and soya products have a low insulin index (Foster-Powell et al. 2002; Blair et al. 2006), it is preferable to choose soya milk over cow's milk to minimise the glycaemic impact and reduce the insulin response. It is possible to integrate these different food scores, to see if there is a common pattern. The satiety score of some common foods is presented in Table 2.10, along with the glycaemic and insulin scores, and the calories. On the satiety scale anything over 100 is more satiety-inducing than the same number of calories (240 kcal) of white bread. Table 2.10. The satiety score, glycaemic score, insulin score, calorie value and fibre content of different foods Satiety*** Glycaemic score score yogurt 88 white bread 100 lentils 133 cheese 146 eggs 150 All Bran 151 wholemeal bread 157 grapes 162 baked beans 168 beef 176 brown pasta, cooked 188 apples 197 oranges 202 porridge 209 potatoes, boiled 323

35** 100* 32* 55** 42** 44* 74* 59* 40* 21** 48* 36* 43* 55* 78*

Insulin* score 115 100 58 45 31 32 96 82 120 51 40 59 60 40 121

Kcal/100g 70 250 85 420 151 62 220 60 49 320 123 50 39 90 75

Fibre/100g g 0 2.5 5.8 0 0 9 6.6 0.7 4.1 0 2.7 1.8 1.7 1.3 1

* Holt et al. 1997 ** Atkinson et al. 2008 *** Holt et al. 1995 Banning All Bran, wholemeal bread , brown pasta, grapes, baked beans, apples, oranges, porridge and potatoes on HPLC diets, all more satiety-inducing than cheese and eggs, runs the risk of patients over-consuming "allowed" foods, and inevitable failure due to uncontrollable urges to consume highly palatable sweet foods such as chocolate. Furthermore, the most filling foods on the list, apples, oranges, porridge and potatoes, are all very low in energy density compared with the less filling foods found typically on an HPLC diet of beef, eggs and cheese.

Note that the satiety index scores do not correlate particularly well with the glycaemic scores of the foods. In the assessment of the role of low GI/GL diets in body weight regulation, the benefits are uncertain. In a scientific review of 51 studies, of the one-day studies, only half indicated that low GI foods reduced hunger and food intake. In the longer-term studies (less than 6 months' duration), weight loss was seen in only one fifth of the studies (Raben et al. 2002). However some scientists do believe that low GI diets can help to reduce body weight (Pawlak et al. 2002; McMillan-Price & Brand-Miller 2006). The latter review quotes numerous examples of advantageous effects on weight loss and satiety of low GI diets. I include some summaries here: when nutrient content has been matched, low GI solid foods induce greater satiety than high GI equivalents, and are followed by a reduced energy intake at later meals (Ludwig 2000); low GI food eaten at breakfast significantly reduces food intake at lunch (Warren et al. 2003); body mass index is positively correlated with the GI of the carbohydrate, but not with the amount of carbohydrate intake or glycaemic load (Ma et al. 2005). It is possible that eating a low GI diet keeps the weight stable, whereas a high GI diet causes weight gain. For example one experiment in rats compared the effect of feeding 2 large meals with a macronutrient composition similar to the Western diet of 45% carbohydrate, 20% protein, and 35% fat, with one group consuming the starch in the form of 100% amylopectin (high GI), and the other group consuming the starch in the form of 60% amylose (low GI) (Pawlak et al. 2000). The calorie values of the diets were the same. After 32 weeks, none of the groups lost weight as the rats were still in their growth phase, but the low GI group were 19% lighter and had 40% less fat mass than the high GI group. Additionally, the high GI group showed decreased postprandial fat oxidation rates compared with the low GI group. They also had twice the liver triglycerides of the low GI group, thus increasing the risk of diabetes. These findings imply that low GI diets can prevent the gradual accumulation of body fat stores. In a subsequent study the researchers adjusted the quantities of food so that the weights stayed the same between the high and low GI groups (Pawlak et al. 2004). This time, after 18 weeks, despite the body weights being similar, the high GI rats had 41% more body fat than and 9% less lean tissue than the low GI rats. They also displayed higher triglyceride concentrations, signs of insulin resistance, lower adiponectin concentrations, and severe disruption of the pancreatic islet cells. In mice, after only 9 weeks, the experiment resulted in a similar increase in body fat in the high GI group. These results indicate that it is right to limit high GI carbohydrates, but unnecessary to limit low GI carbohydrates, as in HPLC diets. Energy density The energy density of a food is the number of calories per gram of food. Fat has a very high energy density of 9 kcal/g, compared with carbohydrate and protein with 4 kcal/g. Fruit and vegetables have a high water and fibre content, and are thus low in energy density (water is 0 kcal/g and fibre has a negligible calorie value as it is not digested).

Thus eating a diet rich in fruit and vegetables lowers the energy density. A review of the impact of fruit and vegetables on body weight confirms that higher body weights are associated with reduced consumption of fruit and vegetables (Tohill 2004). This has implications for HPLC diets which limit fruit and certain vegetables, or ban them completely as in the Dukan diet's initial phase, or allow vegetables only on alternate days as in the Dukan diet's second longer phase, which lasts for months. There is an association between the energy density of the diet and body weight: the lower the energy density of the diet, the lower the BMI, and the higher the energy density of the diet the higher the BMI (Ledikwe et al. 2006). A review of the dietary habits of 7,306 Americans demonstrated that people with a low energy dense diet had lower energy intakes by 430 kcal/day in men and 280 kcal/day in women, compared with people with high energy dense diets, even though they consumed a greater weight of food (by 400 g for men and 300 g for women). These figures correlated with the prevalence of obesity, which was much higher in those consuming a high energy dense diet than those on a low energy dense diet. For example, the energy density of the obese subjects was 1.95 cal/g compared with 1.87 cal/g in the normal weight subjects. People with the highest fruit and vegetable intake had the lowest energy density values and the lowest obesity prevalence. This was particularly marked in those with a low fat intake of less than 30% of overall calories. For example, the prevalence of obesity was 18% in those consuming a high-fat diet (more than 30% fat) in conjunction with less than 5 portions of fruit and vegetables a day. In contrast, in people consuming less than 30% fat and more than 9 portions of fruit and vegetables a day, the prevalence of obesity was only 6%. Eating 5 to 9 portions of fruit and vegetables a day on a high-fat diet slightly lowered the energy density and obesity prevalence (Table 2.11). Table 2.11. The energy density and prevalence of obesity associated with different fat and fruit and vegetable intakes Fat more than 30% F & V less than 5 Energy density kcal/g 2.07 Prevalence of obesity 18%

Fat more than 30% F & V 5-9 1.64 17%

Fat less than 30% F& V more than 9 1.22 6%

F â&#x20AC;&#x201C; fruit portions V â&#x20AC;&#x201C; vegetables portions This study highlights the importance of consuming both a low-fat diet (less than 30%) and a large quantity of fruit and vegetables, in order to reduce the energy density of the diet, energy intake, and body weight. As humans tend to consume a fairly constant amount of food over the course of a few days, lowering the energy density by replacing fat containing foods with fruit and vegetables automatically reduces the calorie content. Note that the optimum amount of fruit and vegetables for weight loss is more than 9 portions a day, greatly exceeding the portions allowed on HPLC diets.

One of the reasons for low energy density diets being associated with low body weights is that high energy density diets can lead to compulsive binge-eating behaviour. Foods made with excessive amounts of fat and sugar are proven to be addictive. One serving is never enough. A study found that rats fed excessive amounts of palatable, energy-dense food (fatty foods such as bacon, sausages and cheesecake) exhibited compulsive bingeeating behaviour, even when consumption of the food resulted in an electric shock (Johnson & Kenny 2010). Autopsies revealed that they had the same brain changes as rats fed heroin and cocaine: a reduction in dopamine D2 receptors in the reward centres. These changes in the brain were due to an initial overstimulation of the D2 receptors in the striatum, leading to a compensatory decrease in their number, and subsequent hyposensitivity to the addictive substance. The rats were then led to self-administer even more of the addictive substance in order to trigger the reward centres. The authors concluded â&#x20AC;&#x153;overconsumption of palatable food triggers addiction-like neuroadaptive responses in brain reward circuits and drives the development of compulsive eating. Common hedonic mechanisms may therefore underlie obesity and drug addiction.â&#x20AC;? The control rats, fed a normal rat chow diet (low in fat and high in carbohydrates), did not exhibit any addiction-like deficits in brain reward function, or binge-eating behaviour. Most HPLC diets encourage consumption of unlimited quantities of fatty meats such as bacon and sausages, the same foods which are known to trigger maladaptive brain changes and addictive eating behaviour. Eliminating such fatty, energy dense foods and substituting with low-fat, plant-based protein alternatives and fibrous carbohydrates would prevent food overconsumption. Enhanced satiety of Quorn (mycoprotein) One easy way to enhance the satiety score of a meal is to include tofu or the mycoprotein meat substitute Quorn, both of which have a lower energy density and fat content than chicken. Research showed that comparing three isocaloric preloads before lunch, one made with chicken, one made with tofu and one made with Quorn, the Quorn and tofu meals resulted in a reduced desire to eat and reduced prospective consumption at both lunch and dinner compared with the chicken meal (Williamson et al. 2006). Another study reported that energy intake at dinner was 18% less following a Quorn lunch, compared with an isocaloric chicken lunch (Burley et al. 1993). These results were backed up by another study which found that overall energy intake reduced by 24% on the day of the Quorn test meal, and this effect lasted over the next day too, resulting in a decreased energy intake of 16.5%, compared with a chicken test meal (Turnbull et al. 1993). The improved appetite control seen with Quorn may be related to its fibre content (4.8g per 100g), as chicken contains no fibre. Quornâ&#x20AC;&#x2122;s other benefits, apart from being less energy dense than chicken yet having a higher satiety score, are that it also helps to reduce glycaemia, insulinaemia and cholesterol. One study found that compared with controls, mycoprotein given in

conjunction with an oral glucose tolerance test reduced glycaemia by 13% and insulinaemia by 19%, 30 minutes post-ingestion (Turnbull & Ward 1995). Another study found that incorporation of mycoprotein into the diet resulted in a decrease in cholesterol by 16% over 8 weeks (Turnbull et al. 1992) The above evidence suggests that if an individual is choosing to follow an HPLC diet because of the perceived enhanced satiety effect, substituting tofu and quorn for the animal protein would result in increased appetite suppression. There would also be greater weight loss, as tofu and quorn contain less fat and calories than chicken or meat. Enhanced satiety of potatoes Potatoes have a higher satiety score than any other food (Holt et al. 1995), are fat free, and have a low energy density (80 kcal/100g) compared with other carbohydratecontaining foods. If they are prepared without the addition of fat, and are eaten in moderation, they can be a tool for weight loss: not only are they extremely filling, they also contain many important nutrients. One medium-sized jacket potato provides a third of the recommended daily allowance (RDA) of vitamin C; a medium-sized serving (175 g) of new potatoes provides 43% of the RDA of vitamin B6; boiled new potatoes in their skins (175 g) provide 38% of the RDA of potassium, and a medium-sized potato in its skin contains more fibre than two slices of wholemeal bread. Potatoes are also a source of folate. Despite these valuable properties, potatoes are banned on HPLC diets. As a final comment on satiety, individuals attending commercial weight loss clinics are often offered appetite suppressant medication. This negates the need for any supposed satiety-inducing mechanism with an HPLC diet. However, these clinics often “jump on the HPLC bandwagon” despite there being no need for an HPLC diet to “reduce hunger”: on medication the patients aren't hungry anyway. The detrimental medical consequences are then completely unnecessary. Thermic effect of food Different macronutrients have different effects on meal-induced thermogenesis. This is the amount of energy dissipated through the digestion, absorption, processing and storing of substrates. For example, a carbohydrate-rich meal induces a higher thermogenesis, compared with a fat-rich meal with the same number of calories (Tentolouris et al. 2003). In addition, the ingestion of glucose, but not protein or fat, causes an increase in betaadrenergic sympathetic nervous system activity, which contributes further to thermogenesis (Welle et al. 1981). It is worth bearing in mind that obese individuals have a lower thermic response to food compared with lean individuals, due there being an inverse correlation between the thermic effect of food and insulin resistance (Watanabe et al. 2006). Although protein also induces a higher thermic response than fat, an HPLC diet consisting of protein and fat would not induce as much thermogenesis as a low-fat diet 30

containing both protein and carbohydrate. Thus an HPLC diet does not maximise the thermogenic potential or increase the metabolic rate as much as could be achieved. Proof of the insignificant effect of the thermic effect of an HPLC diet came after a BBC Horizon programme placed 2 identical twins in sealed chambers for 24 hours to measure exactly how quickly their bodies were burning fuel. One twin had been following an HPLC diet for 2 weeks, whilst the other twin had been following a traditional low calorie high-carbohydrate diet. Analysis illustrated that in 24 hours there was only a 22 calorie increase in fuel burning on the HPLC diet, and less than one calorie was lost in the form of ketones in the urine, compared with the control diet. The researchers concluded that the differences were too small to state that there was a metabolic advantage with the HPLC diet: “The results are what we expected. There’s no difference between the two diets.” (Donnelly 2004).

3. THE SHORT-TERM SIDE EFFECTS OF HIGH-PROTEIN LOWCARBOHYDRATE DIETS What do we know about the short-term side effects of an HPLC diet? The side effects of a low-carbohydrate ketogenic diet have been well documented in children with drugresistant epilepsy (Duchowny 2005), some of whom are put on a ketogenic diet in hospital to control seizures, although the therapeutic mechanism is still unknown. For example, ketogenic diet studies have reported hypercholesterolaemia (in 30%), renal tubular acidosis and kidney stones (in 5%), deficiencies in the B vitamins, calcium and vitamin D (which all have to be supplemented) and spontaneous bone fractures (Vining et al. 2003; Furth et al. 2000). A fuller list of the side effects of low-carbohydrate ketogenic diets was published in a review in Epilepsia, which is summarized here (Hartman & Vining 2007): 1. Metabolic: metabolic acidosis, inadequate growth, hyperlipidaemia, hypoglycaemia (blood glucose has to be monitored), hyperuricaemia, vitamin and mineral deficiency, low levels of sodium, magnesium, calcium, zinc, selenium and copper. 2. Gastrointestinal: nausea and vomiting, constipation, diarrheoa, acid reflux, hypoproteinaemia, acute pancreatitis. 3. Cardiac: prolonged QT interval, cardiomyopathy, lipaemia. 4. Renal: renal tubular acidosis, symptomatic nephrolithiasis. (Citrate is routinely given to combat the risk of kidney stones in those with a family history of nephrolithiasis or those with a high urine calcium:creatinine ratio). 5. Dehydration. 6. Neurological: basal ganglia damage, optic neuropathy secondary to thiamine deficiency, coma. 7. Haematogical: anaemia, easy bruising, leukopenia. 8. Infectious diseases: susceptibility to infection secondary to the leukopenia. 9. Orthopaedic fractures. 10. Abnormal liver function. To illustrate the frequency of the ketogenic diet side effects, I now quote three studies of varying lengths, with figures rounded to the nearest full percentage. One study looking at 129 children, reported the short-term side effects, starting up to 4 weeks on the diet (Kang et al. 2004): these included, in order of frequency, metabolic acidosis (100%), dehydration (47%), nausea and vomiting (28%), diarrhoea (23%), hypertriglyceridaemia (27%), hyperuricaemia (26%), hypercholesterolaemia (15%), infectious diseases (9%),

symptomatic hypoglycaemia (7%), hypoproteinaemia (5%), hypomagnesaemia (5%), hyponatraemia (5%), lipoid pneumonia due to aspiration (2%), hepatitis (2%), and acute pancreatitis (1%). The late onset complications (starting after 4 weeks on the diet) included osteopenia (15%), renal stones (3%), iron deficiency anaemia (2%), hypocarnitinaemia (2%), hydronephrosis (1%) and cardiomyopathy (1%). 4 of the children died (3.1%): 2 from sepsis, one of cardiomyopathy, and one of lipoid pneumonia. 3 of the deaths occurred after only 2 months on the diet (Kang et al. 2004). A 2 year study similarly found a high frequency of side effects on a ketogenic diet: shortterm, children experienced hypoglycaemia (47%) and nausea and vomiting (26%). Longterm, they suffered from raised cholesterol (65%); constipation (41%); severe complications requiring readmission into hospital (21%); symptomatic metabolic acidosis (9%); renal stones (9%); and carnitine deficiency (9%) (Rios 2001). Very long term studies of ketogenic diets in children reveal an even greater renal and skeletal burden: after 6-12 years on a very low carbohydrate diet, the rate of renal stones was 25%, and of bone fractures was 21% (Groesbeck et al. 2006). These patients also suffered from severe stunting in growth (88% were under the tenth centile for height), and the average total cholesterol was also high. The hypercholesterolaemia is often severe: one study in 141 children found that after 6 months, average total cholesterol levels increased by 33% , LDL cholesterol by 49%, triglycerides by 60%, and HDL cholesterol decreased by 23% (Kwiterovich et al. 2003). Detrimental dyslipidaemia occurred in most of the children: 78% had raised total cholesterol, 72% had raised LDL cholesterol, and 86% had raised triglycerides. This dyslipidaemia would be disastrous in any overweight adult following an HPLC diet, as their abdominal obesity would already have increased the risk of abnormal cholesterol levels prior to following the diet, secondary to the metabolic syndrome (to be discussed later). Sudden cardiac death The disturbance of electrolytes on HPLC diets can be severe enough to cause sudden cardiac death. This happened to an American school girl, Rachel Huskey, after only 9 days on an HPLC diet. The paediatricians who investigated her death published a report stating that on autopsy she had critically low levels of potassium and calcium, and it was concluded that the HPLC diet was the most likely cause of her death (Stevens et al. 2002). The abstract is quoted here: â&#x20AC;&#x153;We describe a 16-year-old girl who had sudden onset of cardiorespiratory arrest while at school. She had recently attempted weight loss using a low-carbohydrate/high-protein, calorie-restricted dietary regimen that she had initiated on her own. During resuscitation, severe hypokalemia was noted. At postmortem examination, no other causes for the cardiac arrest were identified. Toxicologic findings were negative. The potential role of the dietary regimen as a contributing factor to the hypokalemia and subsequent cardiac arrest are discussed.â&#x20AC;? In addition to deranged electrolytes, there are several other factors also involved in sudden cardiac death on HPLC diets. Sudden cardiac death was reported in a study which found that two children following a ketogenic diet suffered from a prolonged QT interval 33

associated with selenium deficiency cardiomyopathy (Bank et al. 2008). In fact a prolonged QT interval has been found in 15% of ketogenic diet epileptic patients (Best et al. 2000). This study noted that there was a strong correlation between the presence of a prolonged QT interval and the levels of acidosis and ketosis. Furthermore, 15% also had a dilated cardiomyopathy. In one patient these potentially fatal abnormalities reversed on stopping the diet. This observed cardiac contractile impairment also occurs with high acid levels and ketosis on low-carbohydrate diets: there have been 60 deaths on liquid protein diets in the 1970's and 6 on the Cambridge diet in the 1980's (Wadden et al. 1983). Similar heart damage changes are observed in cases of anorexia nervosa, the cachexia of cancer patients and in very low calorie diets (VLCD), where ketosis occurs. For example one study analysed 17 deaths of individuals following liquid protein diets (300 to 400 kcal) from July 1977 to January 1978 (Sours et al. 1981). The median age of the dieters was 35, the median length of time on the diet was 5 months, and the median rate of weight loss was 2.1kg a week. All were taking multivitamins, and most were on potassium supplementation, with another 8 taking supplements of calcium and magnesium. Despite this, the subjects died: 6 suddenly; 6 after being admitted to hospital following syncope (fainting); 5 suffered from cardiac arrest and never revived; and 7 deaths occurred in the early stages of refeeding. Of the ones who died under observation, all suffered from ventricular tachycardia and ventricular fibrillation. ECGs also recorded decreased voltage in 90%, and all had a prolonged QT interval. It was noted that they had lowered levels of potassium, calcium and magnesium. Autopsies on the hearts of the 17 subjects found evidence of myocardial changes of starvation, myocardial damage, and myocardial atrophy. It was clear that the damage to the heart triggered the contractility changes, which had increased the risk of ventricular arrhythmias and sudden death. After this spate of deaths, VLCD diets were improved in their composition, to include protein of better quality, carbohydrates, essential fats, vitamins and minerals. However, in 4 of the 17 deaths mentioned above, 2 people were on a high quality protein, and 2 were supplementing with protein food for one meal a day, and yet they still died. Another mechanism for sudden cardiac death on HPLC diets is that excessive lipolysis results in an excess of free plasma fatty acids, which is also linked to arrhythmias. Free fatty acids exert several harmful effects on the myocardium, and are a known independent risk factor for sudden cardiac death: high concentrations of free fatty acids have been shown to be pro-arrhythmic, and ventricular tachyarrhythmias are a feature of sudden cardiac death. Raised levels of free fatty acids increase the risk of sudden death by 70% (Jouven et al. 2001). Furthermore, if there are excessive amounts of free fatty acids delivered to the myocardium, this can trigger a metabolic crisis: fatty acid oxidation requires more oxygen compared with the oxidation of glucose. This can trigger a myocardial infarction in anyone with compromised heart perfusion. (Pilz et al. 2007).

Another mechanism for the link between low-carbohydrate diets and cardiac cell death, is that ketone bodies are known to induce insulin resistance in muscle cells. It was observed that in skeletal muscle, beta-hydroxybutyrate inhibited insulin-mediated glucose transport by 90%, after exposure of to physiological ketotic levels for 19 hours (Yamada et al 2010). In cardiac muscle this effect is particularly deadly, as in states of hypoxia the heart preferentially oxidizes glucose over fatty acids for fuel: if glucose cannot enter the cell, the cardiomyocyte cannot function. Studies on cardiomyocytes exposed to ketone bodies report severely impaired glucose uptake in response to insulin (Tardif et al 2001; Pelletier et al 2007). Ketones also induce oxidative stress generation through the overproduction of reactive oxygen species (ROS) in cardiomyocytes, which further prevents glucose uptake (Pelletier & Coderre 2006). These mechanisms could explain the link between insulin resistance and diabetes (ketotic states) and the greatly increased risk of cardiovascular mortality. It should be noted that Dr Atkins himself died (overweight) with a history of arrhythmias, cardiac arrest, cardiomyopathy, hypertension and congestive cardiac failure. Clearly there is an unacceptably high mortality rate on these diets! Commercial HPLC diets warnings on side effects Commercial HPLC ketogenic diets (Pronokal 2010) warn about a long list of side effects including nausea, headache (from hypoglycaemia), constipation, weakness (from hypotension secondary to dehydration and low magnesium, sodium and potassium levels), cramps (from potassium, calcium and magnesium deficiency), changes in the menstrual cycle and amenorrhoea (from increased oestrogen levels), hair loss (from deficiencies in vitamin B, zinc and copper, and essential fats), gout (from hyperuricaemia), feeling the cold (from a lower metabolism), dry skin (from dehydration), and halitosis (from the exhalation of acetone). In one large trial (sponsored by the Atkins Corporation) which collected a detailed symptom diary, the 59 individuals following the Atkins diet reported more episodes of constipation (68%), headache (60%), halitosis (38%), muscle cramps (35%), raised cholesterol by more than 10% (30%), general weakness (25%), and diarrhoea (23%) than those following a low-fat diet (Yancy et al. 2004). One person dropped out due to shakiness and uneasiness. Two of the participants dropped out due to high cholesterol (in one person, the LDL cholesterol went up from 4.75 to 7.31 mmol/l). Another participant suffered from chest pain and was diagnosed with heart disease. The Atkins group all took supplements in the form of 63 different minerals, vitamins, essential fats and other nutritional compounds, presumably to try to prevent detrimental side effects from occurring. Despite this, a large number did suffer from side effects. How dangerous is a diet which is depleted in 63 different essential nutrients? Surely it is better to eat enough fruit, vegetables, whole grains, pulses, nuts and seeds in the first place in order to obtain all the potassium, calcium, magnesium, zinc, vitamins, essential fats and phytochemicals required for health. Is the average person embarking on an HPLC diet going to realise that they need another 63 different supplements to stay alive

and healthy? (These will still not stop the LDL cholesterol levels from rising). An HPLC diet can only be described as severely nutrient depleted. In fact doctors supervising HPLC dieters need to take regular blood samples to assess sodium, potassium, chloride, bicarbonate, urea, and lipids and also perform urinanalysis to monitor protein, ketones, specific gravity and pH. However most HPLC dieters are not medically supervised, having just read about it in a book or magazine: such individuals are even more at risk. Nutritional deficiencies A comparison of the nutritional content of an HPLC diet with a low-fat, highcarbohydrate diet was conducted by Dr Joel Fuhrman, using his highly successful weight loss diet published in Eat to Live (Fuhrman 2011). Both diets have in common an absence of refined carbohydrates such as white bread and sugar, aiming to prevent rapid rises in blood sugar. However on the HPLC diet these foods are replaced by large amounts of phytochemical-poor, saturated fat-containing animal foods, compared with the Eat to Live diet which replaces refined carbohydrates with nutrient-rich fruit, vegetables and legumes. Table 3.1. A comparison of the nutritional content of the Atkins diet and the low-fat Eat to Live diet Atkins diet Calories Protein g Fat g Carbohydrate g Saturated fat g Sodium g Beta carotene mcg Vitamin C mg Calcium mg Iron mg Manganese mg Vitamin E iU Fibre g Chromium mg

Low-fat Eat to Live diet

2550 188 167 67 60 5920 212 30 543 18 1.5 10 5.4 0.034

1600 60 19 314 2 592 8260 625 877 22 8.1 22 77 0.168

In Table 3.1 we can see dangerously high levels of saturated fat in the HPLC diet, accompanied by a severe depletion in vitamins, minerals and phytochemicals. In contrast, the plant-based diet contains hardly any saturated fat, with an abundance of anti-cancer and anti-heart disease phytochemicals. In fact a very high-fibre fruit, nut and vegetable diet has been used to lower cholesterol by 33% (Jenkins et al. 2001).

An analysis of the nutritional composition of food eaten in real life, as opposed to a hypothetical intake from diet book information, has been conducted on dieters following the Atkins diet and other popular diets (Table 3.2) (Gardner et al. 2010). Results reveal a high proportion of the dieters suffering from deficiencies, after 8 weeks of dieting. Table 3.2. Nutritional composition of food as eaten in real life, and percentage of participants with nutritional deficiencies: the Atkins diet (HPLC) and the Ornish diet (high-fibre, low-fat) Atkins (n=73)

Ornish (n=72)

Energy (kcal)

1373

1412

Carbohydrate (g)

58 (17% of E)

220 (63% of E)

Protein (g)

94 (30% of E)

58 (17% of E)

Fat (g)

85 (55% of E)

34 (21% of E)

Saturated fat (g)

31 (20% of E)

10 (6% of E)

Fibre (g)

Folic acid (ug)

329 (55%*)

541 (15%*)

Vitamin C (mg)

66 (52%*)

119 (21%*)

Thiamine (mg)

0.9 (51%*)

1.5 (7%*)

Iron (mg)

10.5 (32%*)

14.2 (8%*)

E â&#x20AC;&#x201C; energy

*Percentage of participants below the Estimated Actual Requirement

The high rate of iron, folate and thiamine deficiency in the Atkins group is despite the participants being encouraged to take multivitamin supplements, and explained by the lack of fortified breads and cereals, which provide the major source of these nutrients in Western diets. The lack of vitamin C is explained by the lack of fruit. Any calorie reduced diet risks nutritional inadequacies due to intake of less food overall, but here we can see that the polar opposite of the HPLC diet has a much lower frequency of nutritional deficiencies for folate, vitamin C, thiamine and iron than the HPLC diet. Furthermore there are much more favourable amounts of saturated fat, fibre and protein: the recommended maximum amount of saturated fat in the diet is less than 10% (NICE 2008), or less than 7% (American Heart Association/Lichenstein et al. 2006), or â&#x20AC;&#x153;as low as possibleâ&#x20AC;? (Institute of Medicine 2005); fibre intake should reach 25 g/day for women and 38 g/day for men (Institute of Medicine 2005); and protein intake should not exceed 20% in diabetics (American Diabetes Association/Bantle et al. 2006).

Thiamine deficiency The perils of ignoring the need to take vitamin supplementation with a low-carbohydrate diet are illustrated by cases in which optic neuropathy developed, causing near blindness, secondary to thiamine (vitamin B1) deficiency. For example two children treated with low-carbohydrate ketogenic diets developed increasingly worsened visual impairment after their parents omitted to give them the recommended multivitamin supplement. After one year on the diet, visual acuity was only 6/24 in one child, and 6/36 in the other child. Bilateral optic neuropathy was diagnosed, and the children's eyesight gradually improved with thiamine supplementation (Hoyt & Billson 1979). In other cases, two adult patients following HPLC diets (one of whom was living on eggs, milk and cheese) also developed bilateral optic neuropathy secondary to thiamine deficiency (Hoyt & Billson 1977). The authors quoted previous animal studies showing that both optic nerve and peripheral nerve degeneration occurs in rats fed a diet deficient in thiamine. Thiamine (vitamin B1) is found in abundance in wheat germ, yeast, whole grain rice, wholemeal bread, and other whole grains, fortified cereals, peas and lentils: foods all absent or severely depleted on an HPLC diet. It is essential for neurological and muscular function. As a water soluble vitamin, it is excreted in the urine, and is not stored in the body. This means that it must be ingested every day to avoid a deficiency, symptoms of which can occur after only 2 weeks. The early neurological symptoms of deficiency include weakness, aching, irritability and depression. This may be accompanied by a burning sensation in the hands and feet, and indigestion. After 2 months of deficiency, there is worsening weakness, with apathy, psychomotor retardation (a slowing down of movements), and impaired memory and cognitive function. As deficiency progresses there is confusion and uncoordination, with severe cases resulting in coma. If the heart muscle is involved, symptoms include palpitations, tachycardia, dizziness, breathlessness, oedema of the legs, and sudden death following heart failure or exertion. Classically thiamine deficiency is common in alcoholics, resulting in the neurological symptoms just described (Wernicke-Korsakoff syndrome). However this is not just confined to alcoholics, and can result from unsupervised and self prescribed weight reduction if there is a lack of thiamine containing foods (World Health Organisation 1999). Unchecked, the neuron loss can result in Alzheimers disease. I wonder how many people following HPLC diets are suffering from weakness, aching, irritability, loss of memory, apathy and depression, not realizing that these symptoms are avoidable had they been consuming a sufficient amount of unrefined carbohydrates such as cereals, oats, wholemeal bread and whole grain rice and pasta. Folate deficiency Folate (also known as folic acid in supplement form) is a water soluble vitamin essential for numerous bodily functions including DNA synthesis and repair. (Folate and folic acid 38

are collectively known as vitamin B9). HPLC diets are often folate deficient, despite the inclusion of green leafy vegetables (Johnston et al. 2006). This could be due to the lack of cereal, pasta, rice, bread, beans and citrus fruit which are all important sources of dietary folate (wheat germ provides the highest concentration on this list). Inadequate folate status is a risk factor for a number of chronic diseases, including cardiovascular disease, some cancers, neuro-psychiatric disease, macrocytic anaemia and complications of pregnancy such as neural tube defects. The link to cardiovascular disease is related to the inverse correlation between plasma folate and plasma homocysteine. There is a well-documented association between raised homocysteine levels and the risk of heart disease, stroke and cognitive decline. Homocysteine is made in the body from the sulphur amino acid methionine. Western diets have an abundance of methionine, due to the high levels of animal products (sulphur amino acids are present in high proportions in animal protein as animals need it to make fur or feathers). Thus excess dietary methionine, typical on an HPLC diet, can result in excess plasma homocysteine if folate is deficient. Folate is essential in maintaining low levels of homocysteine: it is necessary for the remethylation of homocysteine to methionine, which requires folate and vitamin B12. HPLC diets which are deficient in folate have to be supplemented to avoid folate deficiency and its associated complications. What is the minimum amount of carbohydrate needed? There is debate about the minimum amount of carbohydrate needed for body functioning. Looking at the physiological requirements of the body, the minimum amount of glucose needed simply to keep the glucose dependent organs going (brain, neurons, red and white blood cells and renal cortex cells) is 180 g: 135 g for the brain and neurons, and 45 g for the red and white blood cells and the renal cortex cells (Bhagavan 2002). This does not include the fuel required for the muscles or other organs, which can derive their fuel from non-carbohydrate sources such as fat and protein. The US Institute of Medicine recommends a minimum of 130 g carbohydrate a day (Institute of Medicine 2005), and the Association for the Study of Obesity recommends a minimum of 100 g a day (ASO 2004). One review of low-carbohydrate diets states: “The contribution of gluconeogenesis from the body's amino acid stores has been estimated at 55% of endogenous glucose production in normal subjects 5 to 12 hours after a large evening meal thus potentially increasing muscle breakdown... Currently it is estimated that 120 to 180 grams of carbohydrate is necessary for inactive individuals to consume to avoid catabolism of body's protein stores to fuel glucose production.” (Bilborough & Crowe 2003). Loss of muscle mass One of the most comprehensive courses that I have attended was a 3 day course run by the Association for the Study of Obesity on “Obesity and its Management”. There was a presentation on low-carbohydrate diets which stated that a minimum of 100 g of carbohydrate a day is needed to prevent loss of muscle mass. What is the mechanism for 39

this? The conversion of protein into glucose is called gluconeogenesis. Only adequate dietary carbohydrate can prevent the use of protein for energy, and this role of carbohydrate is known as its protein sparing action. Glucose is the preferred energy source for brain cells and other neurons, renal cortex cells, the testes, and developing red and white blood cells. Body fat cannot be converted into glucose to any significant extent. Thus when a person does not replenish depleted glycogen stores by eating carbohydrate, body proteins are broken down to make glucose for the glucose-preferring cells. So eating less than 100 g of carbohydrate a day (as on an HPLC diet) will actually have the opposite effect of the one desired: muscle is lost, not preserved. Metabolic acidosis The lack of inhibition of gluconeogenesis on an HPLC diet is further compounded by the state of metabolic acidosis and lowered glutamine levels, which lead to further loss of body protein. For example, a high-animal protein diet is known to cause a state of metabolic acidosis. Sulphur content, from animal protein amino acids, correlates with renal net acid excretion, as animal protein is metabolised into sulphuric acid. There is also the added acidic effect with an HPLC diet of ketoacidosis, and raised levels of uric acid as a result of consumption of animal purine. This acidic state impairs body protein synthesis and increases protein breakdown, and causes a decrease in thyroid function: all highly undesirable effects if a person wishes to prevent loss of muscle mass and a lowered metabolism when dieting (Metges et al. 2000; Wiederkehr & Krapf 2001). For example, rats with an induced acidosis were found to have increased proteolysis (protein breakdown), increased protein turnover (but with proteolysis greater than protein synthesis), a decreased amino acid pool in skeletal muscle, and more negative protein balance than control rats (Safranek et al. 2003). These changes can be substantial despite only small changes in pH: protein synthesis in skeletal muscle is decreased by 30% at an acidic pH of 7.2, compared with an alkaline pH 7.6 which increases protein synthesis by 130% (England et al. 1991). There is also an increase in amino acid oxidation in metabolic acidosis, which reduces the efficiency of protein utilisation (May et al. 1992). Even more seriously, acidosis-induced whole body protein catabolism (breakdown) includes the heart muscle. This has alarming implications for heart contractility. However, alkalinazion of the body has the opposite effect: it was found that inducing alkaline conditions stimulated protein synthesis, increased cardiac output and slowed protein degradation in rat heart muscle (Fuller et al. 1989). Consuming a diet of soya protein rather than animal protein would result in this desired pH raising effect. Negative nitrogen balance under acidic conditions has also been demonstrated in human studies: induced metabolic acidosis for 7 days caused albumin synthesis to be decreased and urinary nitrogen excretion to be significantly increased. The net result was a protein loss of 8 to 31 g a day, depending on the severity of the acidosis (Ballmer et al. 1995). Metabolic acidosis-induced whole-body protein degradation is further stimulated by the increase in cortisol secretion seen in metabolic acidosis (Isozaki et al. 1996). Furthermore, it is possible to suppress proteolysis (protein breakdown) through correction of metabolic acidosis (Graham et al. 1997). HPLC diets induce loss of body protein via

these mechanisms (despite being high in dietary protein), unless the dietary protein is plant-based and therefore alkali forming. High-protein intake (more than 2g/kg/day) is also accompanied by a decrease in plasma levels of glutamine, and metabolic acidosis in itself also reduces plasma glutamine levels (Metges et al. 2000). As glutamine acts as a fuel for rapidly dividing cells such as intestinal cells and lymphocytes, the result of reduced glutamine is to decrease the number and function of CD4 cells, thus reducing immunological competence. Glutamine is also essential for the regulation of protein homeostasis and gluconeogenesis, so low plasma glutamine levels due to a high-protein intake may impair body protein synthesis even further. Another medical consequence of metabolic acidosis is increased secretion of cortisol (Sicuro et al. 1998). This has potentially devastating effects on the body, through its catabolic actions to provide amino acids for gluconeogenesis in the liver. Muscles, connective tissue, and lymphoid tissue are broken down, causing muscle wasting, thinning skin, poor wound healing and a reduced response to infection. Bone is broken down causing osteopenia. There is an accompanying negative nitrogen (protein) balance, hyperglycaemia, insulin resistance, hypertension, and psychological changes including increased appetite and poor memory. Furthermore, high cortisol levels suppress thyroid function. These are all highly undesirable side effects in anyone, particularly those wishing to lose fat and keep muscle. A 10 day study comparing healthy men on diets with different protein:carbohydrate ratios found that cortisol levels were consistently higher and testosterone levels were consistently lower on an HPLC diet, compared with a low-protein high-carbohydrate diet (44% protein vs. 10% protein) (Anderson et al. 1987). As cortisol has catabolic actions, and testosterone has anabolic and anti-catabolic actions, the optimum condition for athletes to build muscle is actually a low-protein high-carbohydrate diet, as this triggers the perfect combination of low cortisol and high testosterone. What is the possible purpose of acidotic conditions causing loss of muscle mass? It is thought that skeletal muscle, like bone, acts as a pool of base that is gradually depleted to maintain acid-base balance. The released amino acids are broken down to produce the base ammonia. Excess acid is then secreted by the kidneys in the form of ammonium (Sellmeyer 2001). If patients wish to preserve their muscle mass, a minimum of 130 g of carbohydrate a day must be consumed, and any state of acidosis should be avoided to protect the body's protein. Any HPLC diet should have the carbohydrate level increased to prevent these detrimental metabolic effects. Hypothyroidism The Ballmer et al. 7 day study on induced metabolic acidosis in humans reported free triiodothyronine (T3, the active version of thyroid hormone) and free thyroxine (T4, the inactive version of thyroid hormone) to be decreased in states of metabolic acidosis. This

damaging effect of acute acidosis is also seen with chronic acidosis: another human study reported that free T3 and free T4 decreased by 33% and 20% respectively with chronic metabolic acidosis (Brungger et al. 1997). These effects are compounded by higher cortisol levels also suppressing thyroid function. Conversely, correcting metabolic acidosis improves thyroid hormone levels (Wiederkehr et al. 2004). A reduction in thyroid function is compatible with the observed reduction in protein synthesis and lean body mass in metabolic acidosis, as thyroxine has an anabolic (building up) action. Again, it is demonstrated that an HPLC diet has the opposite of a desired effect: muscle mass is lost, not preserved, and metabolism decreases Mental function The brain is a glucose-dependent organ and glucose cannot be stored in neurons. In fact the brain uses up on average 540 calories a day i.e. requiring 135 g of carbohydrate to function properly (Bhagavan 2002). Until the brain adapts to using a high proportion of ketone bodies as a substrate, (it takes around 40 days to achieve using 70% ketone bodies), many adverse mental effects can be seen on a low-carbohydrate diet as a result of this neuroglycopenia (Hein et al. 2004). These include lack of concentration, loss of judgment, poor memory and learning, low mood, emotional lability, anxiety, irritability, lethargy, fatigue and blurred vision. Indeed, there is a very powerful craving mechanism for sweet food which low-carbohydrate dieters complain about, as the brain dictates that it needs glucose immediately. I have seen this in clinical practice with many of my overweight patients, already trying to follow a typical low-carbohydrate diet of eggs and bacon for breakfast, followed by chicken and salad for lunch: by the evening they are so desperate to raise their blood glucose levels that they cave in and consume vast quantities of chocolate. One of my patients who ate chicken salad “every day” for lunch, also ate between 4 and 6 bars of chocolate for dinner, “every day”. She had the worst case of chocolate addiction that I have ever seen! Another one of my patients was an overweight woman in her early forties, who had been trying to follow an HPLC diet for two years. She thought that she was suffering from early dementia due to her poor memory and concentration and inability to perform at work. Her 3 meals a day of “a protein shake, protein and salad, and steak and vegetables” were supplemented in the evening by large quantities of biscuits, as she was driven by an uncontrollable urge to consume sugar. Needless to say both patients were overweight despite long-term dieting. I pointed out to them that if they had allowed themselves a modest amount of slow release complex carbohydrates throughout the day, their blood sugar would be kept at an even keel and they would lose their sweet cravings entirely. Patients are amazed at their immediate cognitive improvement and ability to stop eating sugary snacks, after following my advice to include some fibrous slow-release carbohydrates at each meal. I have seen this advice work time and time again, and lead to substantial weight loss, with the patients reporting feelings of having more energy, better concentration and an improved mood. Indeed, carbohydrate consumption is a well-known trigger for the release of serotonin in the brain, leading to feelings of contentment. Conversely, there is evidence that fat and protein reduce serotonin in the brain (Brinkworth et al. 2009). 42

Serotonin metabolism Serotonin is made in the brain from the amino acid precursor tryptophan. It should be noted that tryptophan itself is found in a vast array of different foods. The plant proteins of soya (0.59 g/100 g), pumpkin seeds (0.57 g/100 g), sesame seeds (0.37 g/100 g) and sunflower seeds (0.3 g/100 g) all contain more tryptophan than turkey, which contains the same amount of tryptophan as peanuts (0.24g/100 g). However simply eating the tryptophan containing food is not enough, as it still needs to enter the brain. It competes for transport across the blood-brain barrier with other large neutral amino acids (LNAAs): tyrosine, phenylalanine, leucine, isoleucine, valine, and methionine. The brain concentration of tryptophan depends on the ratio in the plasma of tryptophan to the other LNAAs: the higher the ratio, the more tryptophan crosses the blood-brain barrier. This ratio depends on there being a reduced concentration of the other LNAAs, which in turn is dependent on the release of insulin, which stimulates the uptake of these branched chain amino acids into non-brain tissues such as muscles. Thus a carbohydrate-rich meal, causing more insulin to be released than a protein-rich meal, will result in a higher plasma tryptophan ratio, a higher flux of tryptophan into the brain, and enable the production of serotonin. Conversely, protein foods lower the plasma tryptophan ratio because they contribute less tryptophan in comparison to other LNAAs to the plasma. The leading researchers into the metabolism of serotonin have published over 40 studies examining the effects of proteins and carbohydrates on the synthesis of serotonin: â&#x20AC;&#x153;The changes in brain serotonin caused by these macronutrients have been proposed as underlying the 'carbohydrate craving' seen in disorders characterized by affective and appetitive symptoms, e.g. seasonal depression, the premenstrual syndrome, smoking withdrawal, and obesity associated with carbohydrate snacking. Conversely, the decreases in brain tryptophan and serotonin caused by low-carbohydrate weight-loss diets might underlie the associated binge eating sometimes seen in female dietersâ&#x20AC;? (Wurtman et al. 2003). One of the studies compared a high-carbohydrate breakfast (waffles, maple syrup and orange juice) with an HPLC breakfast (turkey, eggs, cheese, and grapefruit) on levels of tyrosine and the other LNAAs (Table 3.3). Table 3.3. Nutritional composition of a high-carbohydrate and a low-carbohydrate breakfast in relation to conditions for the synthesis of serotonin Carbohydrate High-carbohydrate breakfast 70g Low-carbohydrate breakfast 15g

Protein 5g 47g

Fat 6g 12g

kcal 347 361

The results showed that with the high-carbohydrate breakfast, from 80 minutes onwards, the ratio of tryptophan-LNAAs increased up to a peak of 120 minutes, with a median increase from baseline of 11%. In contrast, with the low-carbohydrate breakfast, the ratio of tryptophan-LNAAs decreased progressively from 40 minutes, reaching a maximal dip

at 4 hours, and with a median decrease from baseline of -37%. Thus there were optimal conditions for the synthesis of serotonin with the high-carbohydrate breakfast, and inhibition of serotonin synthesis with the low-carbohydrate breakfast. The researchers have devised a highly effective weight loss diet The Serotonin Power Diet (Wurtman & Frusztajer 2010), tackling the common problem of food cravings and lowered mood at 4 pm, and the need to eat after dinner in order to induce relaxation prior to sleep. It is also useful for all women (who make around a third less serotonin than men), and in cases of premenstrual tension, depression, seasonal affective disorder, people who eat when stressed, binge eating disorder, and people trying to lose weight on HPLC diets. This diet is designed to maximise serotonin concentrations in the brain, thus leading to feelings of elevated mood and reduced appetite. It involves eating a small amount of low-fat, low-protein carbohydrate one hour before lunch and dinner, and if necessary one hour before bed. The recommended amount is 30 g of carbohydrate, equal to around 150 kcal. Examples of the carbohydrate snacks include a handful of new potatoes, a small bowl of rice, pasta or cereal, 4 or 5 rice cakes, some pretzels, or some fat-free popcorn. In this way serotonin is synthesized before meals, and less food is consumed during the meal. Another version of the diet is to eat the carbohydrate snack late in the afternoon, and eat a carbohydrate meal for dinner. This could consist of rice, pasta or potatoes with vegetables, or soup with salad and some bread, or a bowl of porridge. One of the reasons for the difficulty in long-term adherence to HPLC diets is due to their causing a decrease in the production of serotonin. One Australian study compared a low-fat diet with a low-carbohydrate diet in terms of mood (Brinkworth et al. 2009). The composition was 46% carbohydrate, 30% fat, and 24% protein for the low- fat diet and 4% carbohydrate, 61% fat and 35% protein for the low-carbohydrate diet. Standard depression inventory and mood score questionnaires were administered before the diet, at 8 weeks, and at one year on the diet. The weight loss was the same after 8 weeks: approximately 13 kg in both groups. All the participants had a negative baseline mood at the start, which improved with weight loss, and was the same in both groups at 8 weeks. However the low-fat group maintained their new improved mood at one year, unlike the low-carbohydrate group, who after 8 weeks returned to their negative baseline mood. The negative effects of low-carbohydrate diets on mood are particularly acute in individuals undertaking exercise. After 3 weeks on a carbohydrate restricted diet, subjects were tested following exercise sessions and were found to suffer from more fatigue, more negative affect and less positive affect, compared with during a 3 week period of unrestricted carbohydrate intake (Butki et al. 2003).

S o u r c e

Pregnancy and mental function HPLC diets are particularly dangerous in pregnancy, as ketones cause a high rate of foetal deaths, and also result in lowered intelligence in the surviving children. The death rates of gestational ketonemia are related to acidosis, a disturbance in electrolytes, and reduced blood flow to the foetus secondary to dehydration (Kamalakaman et al. 2003).

If the child manages to survive, the mental development and intelligence scores are significantly lower (Rizzo et al. 1991). The worse the degree of gestational ketonemia, and the higher the concentration of free fatty acids, the worse the IQ scores are at age 2. The risks of following an HPLC diet in pregnancy should be widely publicised, as many women may mistakenly embark on such a diet whilst trying to get pregnant, or start on an HPLC diet once pregnancy has been confirmed. What is the maximum safe level of dietary protein? Protein is digested into amino acids in the gut and these are then absorbed into the blood stream. The basic structure of an amino acid consists of a carbon, oxygen and hydrogen backbone, but unlike carbohydrate and fat, also has an amino group attached. This consists of one or more ammonia molecules (NH2 or NH3+). Once the body has used up its daily requirements for the production of hormones, enzymes, tissue production etc., surplus amino acids cannot be stored in the body: they must be broken down into glucose or ketone bodies to be used for energy, or converted into fat for storage. In fact net protein synthesis accounts for less than a third of dietary intake: most of the ingested protein is oxidised to provide energy. The byproduct of the metabolism of amino acids (transamination) is highly toxic ammonia. The level of free ammonia in the blood is 1%, and the rest of the nitrogenous waste must be excreted: extra hepatic tissues export their surplus nitrogen in the form of alanine and glutamine in the blood to the liver. This is responsible for the urea cycle, converting ammonia into urea, which can then be safely excreted by the kidneys. However it is apparent that there is a limit to how much urea can be synthesised by the liver (Maximal Rate of Urea Synthesis or MRUS) and excreted by the kidneys: a fixed rate of metabolism of 230 g protein a day (Rudman 1973). Thus any intake higher than this, as is possible on an HPLC diet, risks the underproduction of urea relative to amino acid quantity, and a build up of ammonia can result. When ammonia concentrations exceed the capacity for urea synthesis, ammonia toxicity symptoms occur, resulting from the hyperammonemia. These include nausea, vomiting, and poor cognitive function â&#x20AC;&#x201C; all symptoms seen on HPLC diets. As ammonia is highly soluble and crosses the blood brain barrier, it is a potent neurotoxin, and can cause a condition called hepatic encephalopathy. This occurs in genetic defects where one of the urea cycle enzymes is missing, or in cases of cirrhosis of the liver. It can also be caused by excessive nitrogen load through the ingestion of large amounts protein. The symptoms of hepatic encephalopathy in its mildest form include forgetfulness, irritability and mild confusion. Later symptoms develop of sleepiness during the day and wakefulness at night, with marked irritability and tremor. As ammonia levels rise, difficulties with co-ordination occur, with trouble writing, lethargy and sleepiness. More severe forms cause blurred vision, slurred speech, seizures, coma, cerebral oedema, brain damage and eventual death. Any HPLC diet should therefore specify a limit of how much

protein is consumed, rather than saying “eat freely” on protein foods, due to the potential for protein/ammonia toxicity. The World Health Organiation, Food and Agriculture Organisation of the United Nations and the United Nations University have jointly published an extensive review of dietary protein, including a section on the maximum limit of intake (WHO/FAO/UNU 2007). Numerous research papers were examined, including the Rudman 230 g limit study. I will mention three of them here. Firstly, toxic levels of protein can occur when dietary intake is more than 45% of dietary energy, resulting in nausea and diarrhoea within 3 days, and death in a few weeks: so called “rabbit starvation” (Speth & Spielman 1983). This term derives from anthropological observations where hunting populations dependent on rabbit meat during the winter months perished due to consuming excessive quantities of this lean protein. Secondly, present day hunter gatherers are seen to avoid intakes in excess of 40% protein (Cordain 2000). Thirdly, high-protein intakes have detrimental effects on infants: malnourished infants with kwashiorkor are often misguidedly given high-protein formulas, which are associated with high levels of mortality compared with those given lower protein formulas. In one study, milk protein at 3 times the normal newborn intake, was given to pre-term infants. Short-term they suffered from more fever, lethargy and poor feeding than a lower protein group. In follow-up, the higher protein group had lowered IQs at age 3 and age 6 (Goldman et al. 1974). The World Health Organisation concludes that the recommended safe level of protein intake is 0.83 g per kg of body weight a day, rising to no more than 1.4 g/kg a day, “preferably from vegetable sources” (WHO 2007). Note that the Dukan diet contains 60% protein, even higher than the 45% level known to cause death within weeks as discussed above. This is of serious concern! Gout Focusing on one particular side effect of HPLC diets, I can recount my own clinical experience: I had a previously healthy patient who followed the Atkins diet (consuming lots of bacon, sausages, lamb and steak), but had to give up because he suffered from excruciating painful gout after only one month. This condition disappeared as soon as he returned to a normal diet with less meat. What is the mechanism for the increased risk of gout? Certain proteins containing the purine ring are broken down in the body into uric acid. Purines are found in high amounts in many different animal products: sardines and other fish, liver, kidney, poultry, lamb, pork, beef and game. Uric acid is poorly soluble, and crystallizes easily into sodium urate crystals, which can form permanent deposits in and around the joints and also in the kidneys. The consequence of high uric acid levels can lead to excruciatingly painful gouty arthritis, typically affecting the joint of the big toe but also the fingers, knees and ankles. In the kidney the result is painful uric acid kidney stones.

One prospective study in 47,150 men found that the highest quintile of meat intake resulted in a 41% increased risk of gout, and the highest quintile of seafood intake resulted in a 51% increased risk of gout, compared with the lowest quintile of intake. Conversely the highest quintile of vegetable protein intake reduced the risk of gout by 27% (Choi et al. 2004). As gout is the commonest inflammatory arthritis in men, no man would be advised to follow an HPLC diet unless its main source of protein was vegetable protein. Individual case studies The Physicians Committee for Responsible Medicine (PCRM) set up an online registry to identify people who have suffered from health issues related to HPLC diets (PCRM 2004). The medical complications included gout, osteoporosis, diabetes and cancer diagnoses. Some examples of HPLC diet related side effects are listed below, together with sample comments from some of the registrants: 44% had constipation: “I frequently resorted to laxatives and sometimes went two weeks without a bowel movement”. 40% complained of loss of energy, with one person feeling “exhausted, dizzy, and nauseated before almost passing out on the fifth day of the diet.” Other comments included feeling “so weak I can hardly function” and “after two weeks I felt terribly tired and ended the day with a doughnut binge session”. 40% had bad breath: one person reported having “no energy, and a terrible taste in my mouth all the time” and another complained of “bad breath, funny taste in mouth, feeling lethargic”. 33% reported cardiovascular disease, including heart attacks, atrial fibrillation, coronary arteriosclerosis and high cholesterol: “I believe the diet gave me heart disease” reported one man, who had a clear angiogram at the start of an HPLC diet, but went on to experience angina after two years. A repeat angiogram showed severe artery blockage, necessitating angioplasty and stent replacement. Another registrant described feeling as if “someone was boxing my ears with a very strong throbbing in my neck.” She had to be admitted to hospital secondary to a pulse rate of 210, and was diagnosed with atrial fibrillation, requiring medication. 29% had difficulty concentrating: “I felt horrible. I couldn’t concentrate or focus and felt foggy all the time.” Another registrant stated “I was only on the diet a short time and had a vertigo attack. I have since been out of balance and have a loss of concentration.” 19% of registrants reported kidney problems, with 10% suffering from kidney stones, and 8% suffering from reduced kidney function: “I have recurring kidney infections with elevated leukocytes and blood in my urine. I have tender flanks and am currently under a urologist’s care to find the cause of the blood and the pain.” One man stated that he had 3 kidney stone episodes in 4 months on an HPLC diet.

9% suffered from gall bladder problems: “All I ate was meat and lots of cheese… I ended up having to have my gall bladder removed”. Her doctor had told her that the fatty diet was the cause. (A low-fat diet is the dietary treatment for acute gall bladder inflammation.)

PART 2: THE LONG-TERM SIDE EFFECTS OF HIGH-PROTEIN LOWCARBOHYDRATE DIETS I would like to look at some serious long term consequences of eating a lowcarbohydrate, high animal protein diet. 4. CARDIOMETABOLIC RISK Cardiometabolic risk is defined as an increased lifetime risk of developing cardiovascular disease, which is the leading cause of premature death worldwide. In the UK 28% of the population dies from coronary heart disease or stroke (British Heart Foundation 2010). (27% die from cancer). The main cardiovascular risk factors are hypertension, smoking, diabetes, hyperlipidaemia and metabolic syndrome. The latter is defined by the presence of abdominal obesity, hypertension, hyperglycaemia and insulin resistance, atherogenic dyslipidaemia, inflammation and a pro-thombotic state. Cardiometabolic risk is reaching epidemic proportions, necessitating a central approach to tackle the problem: internationally acclaimed doctors have set up the International Chair on Cardiometabolic Risk, which organises research and conferences on the topic. I attended one such conference and will include some of the key messages here, also incorporating the relationship of HPLC diets to cardiometabolic risk (ASO/ICCR 2010). How might HPLC diets affect cardiometabolic risk? There are several different mechanisms through which HPLC diets affect cardiometabolic risk: beneficially in terms of any weight loss, but detrimentally in terms of dyslipidaemia, insulin resistance, and vascular changes. The only beneficial effect would be any possible weight loss, which would occur on any diet where calories ingested are less than calorie expenditure. However, there is nothing “magical” about an HPLC diet: weight loss results from a reduction in calorie intake rather than metabolic changes associated with differences in macronutrients (Jenkins et al. 2009; Dansinger et al. 2005; Stern et al. 2004). The detrimental effects on cardiometabolic risk of a typical HPLC diet are the result of a diet high in animal products. For example, cardiovascular mortality is increased by 18% with the consumption of red meat, and by 21% with the consumption of processed meat (Pan et al. 2012). Conversely, it has been estimated that 8.6% of cardiovascular deaths in men and 12.2% of cardiovascular deaths in women could be prevented through a reduction in the consumption of red meat to less than 42 g per day (Pan et al. 2012). If the diet is a plant-based, low-carbohydrate diet (not less than 130 g of carbohydrate/day), then there are, in fact, beneficial effects (Jenkins et al. 2009). Here it is important to stress that all animal food contains only protein and animal fat (mostly saturated fat and cholesterol), with no carbohydrate and therefore no fibre at all. Even if “low-fat” sources of protein are eaten on an HPLC diet such as low-fat dairy and egg whites, consuming large amounts of such food could risk the danger of not ingesting enough fibre or phytochemicals. Furthermore, cutting the skin off meat and aiming to eat only “lean” cuts is not sufficient, as much of the saturated fat is hidden within the muscle fibres and impossible to remove. There is a particular problem with beef and lamb where

60% of the fat is intramuscular, and with pig meat the figure is 40%, rendering the fat to be â&#x20AC;&#x153;invisibleâ&#x20AC;? (Geissler & Powers 2005). Plant foods are the only source of carbohydrates and hence fibre, with additional protein and vegetable fats (mostly unsaturated or monosaturated fat, with no cholesterol at all). Plant foods are also an important source of vitamin C, vitamin K, folate, magnesium, potassium, caretenoids and other phytochemicals with essential antioxidant action, protecting against cancer and LDL cholesterol from oxidation, the precursor to atheroma. If we examine the macronutrients of an HPLC diet, unless the diet uses vegan sources of protein such as soya and wheat gluten, a typical HPLC diet is typically high in animal protein and animal fat, and low in plant food, with minimal fibre. The Cardiometabolic Risk conference discussed the role of many different atherogenic biomarkers, with particular emphasis on lipids and uric acid. In summary, the fundamental message was that dietary animal fats and animal protein increase the risk of the development of cardiovascular disease. Firstly, dietary animal fats (saturated fat and cholesterol) have detrimental effects on dyslipidaemia and insulin resistance, both leading to atheroma. Secondly, dietary animal protein (beef, pork and lamb) contains high levels of purines, which results in the production of uric acid: raised levels of uric acid has detrimental effects on the endothelium, causing hypertension and insulin resistance, also leading to atheroma. Should diets be promoted which are high in animal products (meat and dairy), as they lead to increased levels of both lipids and uric acid? I will examine the mechanisms in detail of how HPLC diets can contribute to cardiovascular disease, and how a high-fibre, plant-based diet would have the opposite effect. I will also look at the epidemiology of cardiovascular disease in relation to diet. The broad areas to be discussed here are dietary fat; dietary fibre in relation to insulin resistance and type 2 diabetes; and the vascular effects of low-carbohydrate diets. Dietary fat Current medical guidelines on fat consumption The evidence that saturated fat intake causes dyslipidaemia and an increase in cardiovascular disease is overwhelming, and goes back many decades. NICE guidelines on lifestyle modifications for the primary and secondary prevention of cardiovascular disease recommend a cardioprotective diet: "Total fat intake is 30% or less of total energy intake, saturated fats are 10% or less of total energy intake, intake of dietary cholesterol is less than 300 mg/day and where possible saturated fats are replaced by monosaturated and polyunsaturated fats... at least five portions of fruit and vegetables a day." (NICE 2010). If consuming a daily intake of 2000 kcal a day, this translates to no more than 22 g of saturated fat a day, which would be lowered on a diet of 1400 kcal to 16 g a day. This advice is backed up by the British Medical Journal's Clinical Evidence publication (Thorogood 2006) which advises lowering total fat intake or increasing the ratio of polyunsaturated to saturated fatty acids to lower cholesterol.

The American Diabetes Association agrees with the figure of 10% of total energy intake from saturated fat, but sets the limit at 7% for those with raised cholesterol (American Diabetes Association/Bantle et al. 2006). Going further than this is the American Heart Association, which puts a limit of 7% of total energy intake from saturated fat for the general population (American Heart Association/Lichenstein et al. 2006). However the Institute of Medicine is even more strict about saturated fat, and concludes that an increased risk of adverse events begins when saturated fat intake is above zero. It therefore recommends that with regard to saturated fat, individuals “eat as little as possible while consuming a diet adequate in important other essential nutrients” (Institute Of Medicine 2005). Medical text books also confirm the necessity of reducing saturated fat and cholesterol: I now quote from Davidson's The Principles and Practice of Medicine (Colledge et al. 2010): “Patients with lipid abnormalities should receive medical advice and, if necessary, dietary counseling to: − reduce intake of saturated fat and trans-unsaturated fat to less than 7-10% of total energy − reduce intake of cholesterol to less than 250 mg/day.... Diets deficient in fresh fruit, vegetables and polyunsaturated fatty acids are associated with an increased risk of cardiovascular disease... The main dietary determinants of plasma cholesterol concentrations are the intakes of saturated and trans-unsaturated fatty acids, which reduce LDL receptor activity... Weight loss diets There is no role for starvation diets, which risk profound loss of muscle mass and the development of arrythmias (and even sudden death) secondary to free fatty acids, ketosis and deranged electrolytes... A significant industry has developed in marketing diets for weight loss. These vary substantially in their balance of macronutrients, but there is little evidence that they vary in their medium-term (1 year) efficacy. They all involve a reduction in daily total energy intake of 600 kcal from the patient's normal consumption. The goal is to lose 0.5 kg/week.” Note that this medical textbook confirms that the macronutrient balance of different diets does not determine efficacy at one year: a reduction in calories is the main determinant of weight loss. What are the typical fat contents of HPLC diets? The typical fat content of HPLC and other diets is listed in Table 4.1.

Table 4.1. Typical composition of Atkins, Dukan, Zone and Weight Watchers diets Normal (typical developed country) HPLC high fat (e.g. Atkins) HPLC moderate fat (e.g. Dukan) HPLC moderate fat (e.g. Zone) Moderate fat (e.g. WeightWatchers) Low fat (e.g. Ornish)

% Carbohydrate 50 10 15 40 60 70

% Fat 30 60 26 30 25 13

% Protein 15 30 59 30 15 17

A more detailed analysis of the nutritional composition of some popular weight loss diets, assuming a daily intake of 1600 calories, is listed in Table 4.2. Table 4.2. Nutritional composition of three HPLC diets (Atkins, South Beach, and the Zone) and the Ornish diet Carbohydrate % Carbohydrate g/day Protein % Protein g/day Fat % Fat /day Saturated fat % Saturated fat g Cholesterol mg/day Fibre g/day

Atkins* 5% 20 g 35% 140 g 59% 105 g 26% 46 g 924 mg 4g

South Beach** 33% 132 g 26% 104 g 40% 71 g 11% 20 g 221 mg 22 g

Zone* 28% 160 g 28% 112 g 32% 57 g 7% 12 g 264 mg 18 g

Ornish** 18% 300 g 18% 65 g 7% 12 g 1% 2g 6 mg 54 g

Adapted from: * Anderson et al. 2000 ** de Souza et al. 2008 Here we can see that the low-fat vegetarian diet (Ornish diet) had an impressive 1% saturated fat, but that the South Beach diet had 11% saturated fat, and the Atkins diet 26% saturated fat, greatly exceeding current medical guidelines. Furthermore, higher meat diets tend to increase LDL cholesterol, whereas diets with vegetarian sources of fat and protein tend to decrease LDL cholesterol (Jenkins et al. 2009; Shai et al. 2008; Dasinger et al. 2005; Stern et al. 2004). A meta-analysis of controlled trials reported that Atkins-type diets raise total cholesterol and LDL cholesterol (Nordmann et al. 2006). In fact the author of the South Beach Diet Dr Agatston revealed that that he himself was on heart medication: statins to lower his cholesterol and also aspirin (Witchell 2004). In order to calculate the risk of coronary heart disease from a diet, it is possible to use equations formulated to determine risk factor effects from serum cholesterol and triglycerides, based on the amounts of saturated, monosaturated and polyunsaturated fatty

acids, cholesterol, and fibre in the diet. For example, the Mensink equation is based on dietary saturated fat raising serum cholesterol, and monosaturated and polyunsaturated fat reducing serum cholesterol (Mensink & Katan 1992). The Hegsted formula indicates that every change in dietary cholesterol of 1 mg/1000 kcal predicts a change in serum cholesterol of 0.097 mg/dL (Hegsted et al. 1965). The Brown formula indicates that changes in soluble fibre intake of 1 g/day are associated with a 1.7 mg/dL change in serum cholesterol values (Brown et al. 1999). One such analysis was conducted on 8 different weight loss diets: 4 in the HPLC category including Atkins, and the Zone, and 4 with normal amounts of protein and carbohydrate such as the low-fat Ornish diet (Anderson et al. 2000). A baseline “typical American diet” and serum cholesterol of 200 mg/dL were used. The results were that the Atkins diet had the worst score, with a predicted serum cholesterol of +51 mg/dL (+26%), whilst the Ornish diet had the best score with -63 mg/dL (-32%). These predicted changes in serum cholesterol values were in the range of the authors' previous metabolic ward feeding studies. The authors state “Since every 1% change in serum cholesterol values are estimated to produce a 2% to 3% change in risk for coronary heart disease, long-term use of the Ornish diet might decrease risk of coronary heart disease by more than 60%, while long-term use of the Atkins diet might increase risk for coronary heart disease by more than 50%.” A second score was determined based on the diets' abilities to achieve recommended nutritional requirements in terms of sufficient grains, fruit and vegetables, and avoidance of excessive amounts of meat and fat, as stated in consensus guidelines. The goal was to reach a score of 11 or more. The results were that all four HPLC diets had negative scores, ranging from the Atkins diet with -22.9 to The Zone with -3.6, whilst the normalcarbohydrate, normal-protein diets all had positive scores, with two low-fat, highcarbohydrate, high-fibre diets greatly exceeding the goal of 11, scoring the highest with values of +24.6 (the Ornish diet) and +25.5 (the Pritikin diet). The Pritikin diet advocates eating mostly plant-based, high-fibre foods, rich in high-fibre complex carbohydrates, fruit and vegetables, and low in energy density. Meat and fish is limited to 100 g a day, with no egg yolks or full fat dairy products. The Ornish diet is a vegetarian diet rich in high-fibre complex carbohydrates, fruit, vegetables and pulses. On the topic of serum triglycerides, the Anderson et al. diet comparison paper states that high-carbohydrate, low-fibre diets increase fasting serum triglycerides, but that highcarbohydrate, high-fibre diets either do not effect or decrease fasting serum triglycerides. For example, it has been shown that high-fibre diets lower triglyceride values by 10.2%, cholesterol by 6.7%, LDL cholesterol by 6.3% and plasma insulin concentrations by 12% (Chandalia et al 2000). The authors go on to say “High fat diets increase postprandial hypertriglyeridaemia and increase the concentration of atherogenic chylomicron remnants. The postprandial triglyceride rise is related to the amount of fat in the meal, indicating that high fat meals are followed by significantly higher triglyceride concentrations than low fat meals. These postprandial triglyceride-rich particles and remnant particles appear to be substantially more atherogenic than fasting VLDL particles. During the weight loss phase, these risks may be smaller; however, if one continues these diets in a weight-maintaining state, the risk of accelerated atherosclerosis and atherosclerotic events may be substantially increased... Diets high in

animal fat appear significantly related to higher risks for coronary heart disease. Highfibre intakes, especially whole grains, appear to protect from coronary heart disease and diabetes.... Animal studies and human studies indicate that high-fat diets are associated with insulin resistance.... the only proven weight-maintaining dietary interventions for improved insulin sensitivity are higher carbohydrate, higher fibre, lower fat diets... Deprivation of dietary carbohydrate results in impaired glucose tolerance due to insulin resistance. Reduction in dietary carbohydrate also increases postprandial free fatty acid concentrations in association with impaired glucose tolerance. Our studies indicate that high-carbohydrate, high-fiber,low-fat diets are accompanied by lower FFA values than low-carbohydrate, low-fiber, high-fat diets. Since FFA concentrations are a strong predictor of insulin sensitivity, higher FFA levels with high fat diets would be associated with less insulin sensitivity than lower fat diets. Many government agencies, expert advisory boards and disease panels have recommended higher carbohydrate, higher fiber, lower fat -especially saturated fat— diets in many Western countries. There is a growing consensus around the recommendation for 6 to 11 servings of cereals—breads, breakfast cereals, rice, and pasta including three servings of whole grain foods—3 to 5 serving of vegetables and 2 to 4 servings of fruits per day. We have concerns about making alternative recommendations for overweight or obese individuals who already have increased risk for CHD, diabetes, hypertension and certain forms of cancer. Whole grains, fruits and vegetables are rich sources of fiber, antioxidants, phytoestrogens and other phytochemicals. Generous intake of these foods is associated with a significant reduction in risk for CHD, cancer, and diabetes. Finally, through the evolution of the ancestors of man plant-based, high fiber, low animal fat diets were consumed. Stone tools and cooking methods sufficiently advanced to allow significant meat intake did not become available until the Paleolithic period. For 5 to 15 million years of the Miocene before the present time, consumption of highfiber plant foods and exercise shaped the human genome. Such diets provide very little stimulus for cholesterol synthesis and greatly increase faecal bile acid losses compared with contemporary diets. The simian-like diets demonstrate a 30% decrease in serum LDL-cholesterol concentrations similar to those predicted for the Ornish diet. The evolutionary argument therefore provides a further reason for favoring high-fiber, lowanimal fat diets.” An analysis of the diet of a sample of poorly controlled diabetic individuals revealed an alarming trend in terms of macronutrient composition (Ma et al 2006). Despite the exclusion criteria being the current following of a formal HPLC diet, the daily carbohydrate intake was only 159 g and the fibre intake was only 11.4 g. With an average caloric intake 1778 kcal, the overall the diet was composed of 35% carbohydrate, 20% protein, and very high levels of fat (45% fat:15% saturated fat;17% monosaturated fat; and 9% polyunsaturated fat). This low-carbohydrate pattern of eating was associated with many unhealthy risk factors for cardiovascular disease: 95% were overweight or obese,

and 77% were obese; the glycaemia was poorly controlled with an average HbA1C of 8.3%; hyperlipidaemia was present in 77.5%, with 98% taking lipid lowering medications; 67.5% were hypertensive; and 15% had heart disease. The average depression score indicated mild depression in most of the subjects. The authors noted that carbohydrate consumption had, in 10 years, decreased by approximately 10%, and fat had increased by approximately 10%, due to the replacement of fibrous carbohydrates with foods high in saturated fat. They reflected that the reason for this could be a general trend to reduce carbohydrates, due to the influence of popular HPLC diet books in this time. The consequence was a rise in detrimental cardiovascular risk factors, as it has been shown that a 1% reduction in LDL cholesterol corresponds to a 1-2% reduction in occurrence of coronary heart disease events. Any diet recommended by a health professional should aim to reduce LDL concentrations. Case study of an HPLC diet associated with angina One interesting case study of the Atkins diet is illustrated by a 53 year old American business man, Jody Gorran, who slavishly followed the Atkins diet, but ended up suing the Atkins Corporation after suffering a massive angina attack (Gorran 2004). Before embarking on the diet he had his blood lipid levels measured and a CT scan of his heart. It was confirmed that his total cholesterol and LDL cholesterol were normal, and there was no evidence of atherosclerosis in his coronary arteries. After only two months, his cholesterol and LDL cholesterol levels had nearly doubled. Despite this he continued with the diet, until he suffered from a severe angina attack 35 months later. Investigations revealed a 99% stenosed (narrowing) in one of his coronary arteries. He underwent an emergency angioplasty to remove the blockage, and his cardiologist advised him to stop the diet. Since then his cholesterol levels returned to normal. He sued the Atkins Corporation for failing to provide adequate warnings about the increased risk of cardiovascular and other diseases on the diet, and for making false statements that the diet was safe. The lawyers for the Atkins Corporation actually admitted in court that the diet was dangerous (PCRM 2005). In fact there have been many other cases of individuals suing the Atkins Corporation for similar failings, after developing cardiovascular disease as a consequence of following the Atkins diet (Greger 2004). The cases were settled out of court in favour of the plaintiffs. Saturated fat Consuming saturated fat is a well known risk factor for dyslipidaemia, a major determinant of atherosclerosis. The consequence depends on which arteries are affected: Coronary arteries: angina and myocardial infarction (heart attack) Cerebral circulation: transient ischaemic attack and cerebrovascular accident (stroke) Renal arteries: hypertension and renal failure Mesenteric arteries: acute intestinal ischaemia

Limbs: intermittent claudication, critical limb ischaemia and amputation In the UK, 60% of the population have cholesterol levels of at least 5 mmol per litre (anything over 3.8 raises the risk of heart disease) (Cardiac Matters 2010). In fact NICE states "In high income countries cholesterol levels in excess of 3.8 mmol/litre are responsible for more than 50% of cardiovascular disease events. Blood cholesterol can be lowered by dietary change." (NICE 2010). Epidemiology and cardiometabolic risk factors What has caused this high level of cholesterol? The evolution of fat intake shows an interesting change (Mouton 2006): 200 years ago, total fat intake was around 22%, with only 8% of total calorie intake being saturated fat. There was a steady rise in both total and saturated fat intakes from the 1820's, reaching today's Western intake of around 37% total fat, with 20% of total energy intake being saturated. (Traditional Japanese and Chinese cultures have a fat intake of only 14%). Factory farming, started in the 1940's, made meat and dairy foods cheaper, increasing their consumption to now a daily habit, with subsequent detrimental increases in dietary saturated fat and cholesterol intake. Intensive farming has also caused the fat content of chicken to more than double since 1940, due to both industrialized feed and the severely restricted movement of the birds in high-stocking-density sheds (Wang et al. 2004). The increase in the level of saturated fat intake is also reflected in the typical Western diet's poor ratio of polyunsaturated fat to saturated fat of 0.4/1. There is in fact no physiological need for any saturated fat at all in the diet (the body makes its own saturated fat and cholesterol as needed). What do we know about cardiometabolic risk factors from epidemiology? The fact that a high level of dietary saturated fat and cholesterol is one of the major causes of cardiovascular disease has been known for decades. As far back as 1961, the results of the Framingham study in the USA showed clearly that cardiovascular disease was strongly linked with a high intake of animal fat (Kannel et al. 1961). These findings have been confirmed time and time again. Professor Colin Campbell's The China Study (published in the American Journal of Clinical Nutrition and in book form in 2006, and essential reading for all health professionals), is a ground-breaking study looking at disease incidence and death rates in 880 million Chinese citizens. He is the Professor Emeritus of Nutritional Biochemistry at Cornell University and his team included Sir Richard Peto's team at Oxford University. It is the most comprehensive study of nutrition ever conducted. It analyzed food, blood and urine samples, and diet questionnaires in 6,500 adults from 65 rural counties across China. 48 different kinds of disease were examined, along with 36 different food constituents (nutrients, pesticides, heavy metals), and 109 nutritional, viral, hormonal and other indicators in the blood. I do not have the space to report all the many important findings, but to summarize one key point, it was reported that the greatest single influence on the growth of degenerative diseases such as cardiovascular disease, cancer and type 2 diabetes is the amount of animal fat and animal protein eaten. For example, in rural China animal protein is only 7% of total protein intake (compared with 62% in the UK), and cholesterol levels are between 2.5 and 4 mmol per litre. In the UK, as stated earlier, 60% of us have levels over

5 mmol per litre. There was a direct correlation between the amount of animal protein eaten and heart disease incidence. The study also observed that replacing animal protein (casein) with soya protein reduced blood cholesterol, even when the fat content remained unchanged. There were incredibly low rates of coronary heart disease (CHD) in rural China: the death rate from CHD was 17 times higher among American men than rural Chinese men. For example, during the three year observation period, not one person died of CHD before the age of 64, among 246,000 men in a Guizhou county and 181,000 women in a Sichuan county! Compare this to the autopsy results, published in the Journal of the American Medical Association, on 300 young fit US soldiers killed in Korea (average age 22): 77.3% had some evidence of heart disease (Enos 1953). One large scale study looking at cholesterol levels found that vegans had the lowest levels, vegetarians had intermediate levels, and meat eaters had the highest levels: as meat and cheese consumption rises, so does serum cholesterol. Vegetarians have lower cholesterol levels on average by about 0.5 mmol/l than meat eaters. Table 4.3 is taken from the Oxford Vegetarian Study, which followed up 6000 vegetarians and 5000 nonvegetarians over 12 years (Appleby 1999). Vegans ate no animal products; vegetarians ate no meat or fish but did eat dairy products, eggs, or both; and fish eaters ate fish but no meat. Table 4.3. Plasma lipid concentrations by diet group, adjusted for age and sex Dietary group

Total cholesterol LDL cholesterol mmol/L Vegans (n = 114) 4.29 ± 0.140 2.28 ± 0.126 Vegetarians (n = 1550) 4.88 ± 0.100 2.74 ± 0.090 Fish eaters (n = 415) 5.01 ± 0.109 2.88 ± 0.098 Meat eaters (n = 1198) 5.31 ± 0.101 3.17 ± 0.091 Heterogeneity P < 0.001 P < 0.001 Here we can see that serum total cholesterol and LDL cholesterol rises from the lowest levels in vegans and vegetarians, to higher levels in pescatarians, to the highest levels in meat eaters. Note that NICE states that the aim is to keep total cholesterol less than 4 mmol/litre and LDL cholesterol less than 2 mmol/litre (NICE 2010). Thus when deciding on a diet for weight loss it is logical to opt for an eating pattern which results in the lowest levels of serum cholesterol and LDL cholesterol. HPLC diets, heavy in meat, increase total cholesterol and LDL cholesterol. All cause mortality was reduced by 54% in the vegetarians. After adjusting for smoking, BMI and social class, vegetarians had a 20% reduced chance of dying from all causes, a 28% reduced chance of dying of ischaemic heart disease and a 39% reduced chance of dying from cancer.

Looking at the dietary nutrient intake, there was a strong positive association between the highest third of intake of animal fat and cholesterol and ischaemic heart disease versus the lowest third: there was a death rate ratio of 3.29 for total animal fat and 3.53 for dietary cholesterol. Thus there was a more than 3-fold risk of CHD with the highest third consumption of animal fat. Consumption of eggs and cheese were both positively associated with ischaemic heart disease. The mean dietary nutrient intake is summarised in Table 4.4. Table 4.4. Dietary nutrient intake for vegans, vegetarians, fish eaters, and meat eaters (men) Vegans Protein % energy 11.3 Carbohydrate % energy52.5 Fat % energy 33.5 Sat. fat % energy 6.2 Poly.:sat. ratio 1.85 Cholesterol mg 7 Fibre g 55.3

Vegetarians 12.2 47.7 36.4 12.1 0.73 267 41.8

Fish eaters Meat eaters Heterogeneity 13.6 14.6 0.001 43.8 43 0.001 38.2 38 0.045 12.5 13.2 0.001 0.73 0.56 0.001 260 306 0.001 37.4 35.0 0.001

Here was can see that there is a non-desirable trend in nutrient factors the more animal products are consumed, along with higher protein and lower carbohydrate scores. In an HPLC diet this trend would be even more exaggerated, with even less favourable outcomes in terms of total and LDL cholesterol! Translated into morbidity and mortality outcomes, the researchers concluded that â&#x20AC;&#x153;on the basis of these results, it was predicted that the incidence of ischaemic heart disease might be 24% lower in lifelong vegetariansâ&#x20AC;?. The Oxford Vegetarian Study was included in one major analysis on 5 prospective studies involving 76,172 people from the UK, USA, New Zealand and Germany. The pooled data showed that lacto-ovo vegetarians have a 34% lower risk of dying from heart disease, compared with non-vegetarians eating meat at least once a week, even after adjusting for age, sex, smoking, education level, exercise level and BMI (Key & Fraser et al. 1999). Overall, heart disease mortality was reduced by 24% in vegetarians compared with non-vegetarians. Furthermore, the German component of the study found there to be a 55% lower risk of fatal ischaemic heart disease in the vegetarians compared with the non-vegetarians. The association between a plant-based diet and reduced death from ischaemic heart disease became even stronger in the younger age groups: cardiac mortality in those under the age of 65 was 45% lower in vegetarians. The major determinant of these statistics is the lowered level of cholesterol in plant-based diets. The study reported that cholesterol was lower by between 0.33 and 0.61 mmol/l in the vegetarians. This result supports other studies stating the vegetarians have significantly lower levels of cholesterol than meat eaters, by about 0.5 mmol/l (Sacks et al. 1985; Key & Davey et al. 1999).

The Adventist Health Study was one of the studies analysed in the Key and Fraser research mentioned above. Seventh-day Adventists are a useful population to examine, as they do not smoke or drink alcohol, and hence such confounding variables are already controlled for. The data from this particular study, on 34,192 California Adventists, revealed even stronger effects for diet: the lifetime incidence of ischaemic heart disease was reduced by 37% in vegetarians compared with non-vegetarians (in men). Types of meat were also examined. Consuming beef more than 3 times a week was associated with an increased risk of fatal ischaemic heart disease of 2.31 times, compared with eating a vegetarian diet. In fact US research has shown that official advice to eat "lower fat" by avoiding fatty cuts of red meat, switching to white meat and fish, and switching from butter to margarine only lowers cholesterol by about 5%, whereas following a vegetarian diet results in significantly greater reductions (Kestin et al. 1989; Ornish et al. 1990). Could these observational studies' results aid in the treatment of dyslipidaemia and existing CHD? Important research (published in The Lancet) are by Dr Dean Ornish, an American cardiology consultant, whose best-known work is the Lifestyle Heart Trial, where he managed to reverse heart disease using diet alone (Ornish et al. 1990; 1998). He compared two sets of his patients who all had heart disease, severe enough to warrant surgery. Instead of surgery they were offered a one year lifestyle programme. One group he kept on their usual heart medication, and were recommended to follow a typical "healthy heart" diet (30% of calories from fat), and the other group were actually taken off their usual medication, with a recommendation to follow a plant-based diet with only 10% fat. The latter were allowed to eat as much food as they wanted, as long as it was from an acceptable food list, which included fruits, vegetables, pulses and grains. No animal products were allowed except for egg white and one cup per day of non-fat milk or yogurt. Soya and legume protein was emphasized. Analysis of the average nutritional content of the diet found that it contained only 8.5% fat, equal to 17 g of fat a day at 1846 kcal. There was only 19 mg of cholesterol a day. The control group ate on average 25% fat, equal to 44 g of fat a day on 1573 kcal a day. The cholesterol intake was 139 mg a day. After one year on the plant-based diet, 82% had regression of their heart disease, despite being on no medication. Arteriography showed shrinkage of the blockages, LDL cholesterol levels were lower by 40%, and the frequency of chest pain was reduced by 91%. There was also remarkable weight loss of an average of 11 kg, despite this group eating more calories than the control group, who lost nothing. The control group actually had worsened atherosclerosis and cardiometabolic risk factors, despite being on medication, with a rise in chest pain frequency of 165%, and no weight loss. The LDL cholesterol reduced by only 5%. At 5 years arteriography showed continued shrinking of the blockages in the plant-based group, and there were less than half as many cardiac events than the usual care group. The usual care group had progressively worsening stenosis throughout the 5 years. Clearly a 30% fat diet is not low enough! The programme was so successful, that it is now being conducted on a large scale across 8

sites and his heart disease treatment plan is now covered by a number of different insurance companies. The programme started in 1993, and by 1998 200 people had taken part, with 65% eliminating their chest pain after one year of treatment. American cardiologist, Dr Caldwell Esselstyn, has had similar success in reversing heart disease using plant-based nutrition (Esselstyn 2001). He offered seriously ill patients, who had had failed interventions such as angioplasty and bypass surgery, an exclusively plant-based diet, in conjunction with their usual lipid lowering medication. The diet consisted of wholegrains, vegetables, fruit and legumes, with no animal products at all. Of those who maintained the diet, they experienced a profound drop in cholesterol: it reduced from an average of 246 mg/dL to an average of 137 mg/dL. In addition, symptoms were relieved, and there was no recurrence of coronary events in 12 years. Patients lost weight, blood pressure normalized, and type 2 diabetes, erectile dysfunction, angina, peripheral vascular disease, and carotid disease all improved or resolved. Angiography at 5 years proved that none had progression of the disease, and 70% had significant regression of the coronary blockages. A description of the diet and details of the study, which has now been running for 20 years, are described in Prevent and Reverse Heart Disease (Esselstyn 2007). As patients with a raised BMI have an increased risk of cardiovascular disease, a cardioprotective diet (i.e. plant-based) should form the basis of any weight loss diet. Case study: Bill Clinton Former US president, Bill Clinton, had been suffering from chest pain for years, but it was not until in 2004, during a book tour, that he was rushed to hospital with a severe angina attack. He underwent an emergency quadruple bypass operation. However, six years after the operation his bypass failed, and he had to have two stents inserted to open up his arteries. It was then that he resolved to adopt a strict plant-based diet, using dietary guidance from Dr Dean Ornish and Dr Caldwell Esselstyn, with the aim of avoiding any further recurrence of cardiac events. Dr Dean Ornish worked closely with Bill Clinton’s chef, substituting his favourite unhealthy fast food with soya burgers. A US documentary was made on how to prevent and reverse heart disease through nutrition, which featured Bill Clinton talking about his health and diet, and included interviews with Dr Dean Ornish and Dr Caldwell Esselstyn (CNN 2011). Bill Clinton was described as eating “nothing that has a mother or a face.” He stated “I like the stuff I eat. I like the vegetables, the fruit, the beans”. When asked if he was a vegan, he replied “Well, I suppose I am if I don’t eat dairy or meat or fish.” When asked if he considered himself to be healthy now, he said “Well, I think I'm healthier than I was. You know, I lost 20-something pounds. All my blood tests are good. All my vital signs are good and I feel good. I actually believe it or not have more energy. I seem to need less sleep.” Dr Esselstyn was asked for some easy-to-remember adages about what people should or should not eat. He said “We know what they shouldn’t eat. That is oil, dairy, meat, fish

and chicken. What do we want them to eat: We want them to eat all those whole grains for their cereal, bread and pasta, beans, vegetables â&#x20AC;&#x201C; yellow, red, green â&#x20AC;&#x201C; and fruit.â&#x20AC;? Mechanisms of saturated fat-mediated damage One of the key messages from the International Chair on Cardiometabolic Risk is that dyslipidaemia not only causes atheroma, but that it also causes impaired insulin signaling which leads to insulin resistance, which further increases the risk of cardiovascular disease (ASO/ICCR 2010; Ferrannini et al. 1983; Kennedy et al. 2009). In fact it is all a vicious circle because insulin resistance itself also causes arterial stiffness and dyslipidaemia, so the risk of cardiovascular disease increases even further. Elevated postprandial concentrations of free fatty acids also have damaging effects on clotting and may cause ventricular arrhythmias. Indeed, the development of arrhythmias is further compounded by the deranged electrolyte balance seen in HPLC diets, which can be fatal (Pronokal 2010). (There have been several high profile cases of young women dying on low-carbohydrate diets, as mentioned earlier.) Plant foods contain mostly polyunsaturated fat or monosaturated fat, so do not pose the same risk as animal fats. Which particular saturated fats are the most atherogenic? The two saturated fats with the worst atherogenic profile are myristic acid and palmitic acid (Mouton 2011). Myristic acid is the most atherogenic out of the two, and is found in dairy products, coconut and palm oil. Palmitic acid is found in butter, pork, beef, lamb, eggs, palm oil and chocolate. Both of these saturated fats raise cholesterol and cause atherosclerosis. With regard to saturated fat, what other mechanisms could contribute to disease? One is that saturated fat inhibits the action of delta-6-desaturase, the enzyme responsible for the first rate limiting step in the formation of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) from alpha linolenic acid (omega 3 fatty acids) (Mouton 2011). As EPA acts as a precursor to the anti-inflammatory prostaglandin 3 (PGE3), and also blocks the synthesis of pro-inflammatory eicosanoids from arachidonic acid, the net result of consuming saturated fat will be the loss of anti-inflammatory, antiallergy, vasodilatory, anti-autoimmunity and anti-platelet aggregation functions. Delta-6desaturase also acts on linoleic acid (omega 6 fatty acids) to form gamma linolenic acid, which is needed for the synthesis of the anti-inflammatory prostaglandin 1 (PGE1). When this is deactivated by saturated fat, the anti-inflammatory, immunostimulant, vasodilatory, and anti-platelet aggregation functions of PGE1 are also lost. Saturated fat-mediated inflammation and insulin resistance Dietary saturated fat can have adverse effects on insulin sensitivity (Xiao et al. 2006; Vessby et al. 2001). In the former study, insulin sensitivity was impaired after only 24 hours on a diet very high in saturated fats (45%). The latter study demonstrated that consuming a high (17%) saturated fat diet for 3 months impaired insulin sensitivity by 12.5%, compared with a low saturated fat diet (8%), which improved insulin sensitivity by 8.5%, irrespective of any weight change. (Both diets contained up to 37% fat overall, with the same amount of protein and carbohydrate). The authors discussed how dietary

fat is directly related to plasma fatty acid composition, which is in turn related to the composition of phospholipid membranes: a high proportion of long chain unsaturated fatty acids and a low proportion of saturated fatty acids is related to increased insulin sensitivity in humans, whereas a high proportion of saturated fatty acids and a low proportion of long chain unsaturated fatty acids is associated with insulin resistance. These changes in cell membrane structure affect insulin receptor binding activity, ion permeability and cell signaling. Other mechanisms for the link between saturated fatty acid intake and insulin resistance are discussed below. The Atkins diet is 26% saturated fat (St Jeor et al. 2001) and 23% in the maintenance phase (de Souza et al. 2008), higher than the detrimental level of 17% as discussed above, so is ill-advised because of its inevitable detrimental effect on insulin sensitivity. Conversely a reduction in dietary saturated fat is associated with increased insulin sensitivity, regardless of weight loss (Lovejoy 2002; Riccardi et al. 2004). Saturated fat intake has been proven to cause chronic inflammation and insulin resistance. The result is metabolic syndrome. There are numerous mechanisms by which this occurs. In vivo and in vitro studies provide evidence that intake of saturated fat causes dysregulation in white adipose tissue. An excellent review of this topic is published in The Journal of Nutrition: â&#x20AC;&#x153;Specifically, excess consumption of saturated fatty acids enhances white adipose tissue expansion and adipocyte hypertrophy and subsequent death. These events increase inflammatory signaling and recruitment and activation of macrophages and neutrophils, and bone marrow-derived dendritic cells, leading to inflammation, impaired insulin signaling and insulin resistance in multiple tissues, especially in white adipose tissue and muscle.â&#x20AC;? (Kennedy et al. 2009). The examples given of the mechanisms of inflammation and insulin resistance include: saturated fatty acids in human adipocytes trigger oxidative stress and inflammatory mediators, thereby causing inflammatory gene expression. This process is enhanced by endoplasmic reticulum stress leading to apoptosis (cell death), resulting in free fatty acid release and further inflammatory gene expression. The net result is insulin resistance. Inflammation is further increased as saturated fatty acids are particularly potent in recruiting and activating macrophages in white adipose tissue. The net result of all this inflammation is insulin resistance. Saturated fat also impairs insulin sensitivity in adipocytes by reducing adiponectin secretion and impairing insulin signaling pathways required for glucose uptake. Furthermore, saturated fatty acid also directly causes inflammation and insulin resistance in muscle: there is a strong association between intramyocellular lipid accumulation and insulin resistance. In one study, slim, healthy, young adults with a family history of type 2 diabetes, were tested for insulin resistance (Petersen et al. 2004). Of those who were insulin resistant, analysis of the muscle cells revealed microscopic droplets of fat. Muscle cells normally store small amounts of fat as an energy reserve, but in the insulin resistant subjects, the intramyocellular fat was 80% more than those without insulin resistance. Thus a high saturated fat diet causes increased uptake of fat into the muscle cells, and subsequent insulin resistance.

Other studies (Delarue & Magnan 2007; Morino et al. 2006) have confirmed the strong correlation between intracellular triglyceride storage in muscles and liver and insulin resistance in these two tissues, but what is the mechanism for this? One of the many mechanisms is that dietary saturated fat increases the expression and secretion of inflammatory cytokines in skeletal muscle, impairing insulin sensitivity in muscle cells: intracellular accumulation of diacylglycerol activates protein kinase-C, which in turn phosphorylates serine residues in insulin receptor substrate-1 (Andreelli et al. 2009). This results in decreased intracellular insulin signaling i.e. insulin resistance. Another mechanism is that saturated fatty acids antagonise the PPARy coactivator PGC-1 alpha. As this promotes mitochondrial oxidative phosphphorylation and insulinstimulated glucose uptake, the net result is a decreased oxidation of fatty acids and glucose, thereby increasing their accumulation in the muscle cells, blood and other tissues (Sparks et al. 2005; Kennedy et al. 2009; Hoeks et al. 2010). In the former study, healthy young men were put on a 50% fat diet. After only 3 days, intracellular lipids had increased considerably, and the genes which normally help mitochondria to burn fat had been turned off. Thus a high-fat diet causes the accumulation of fat in the muscle cells while also reducing mitochondrial function and slowing down the ability of the body to burn fat: a dual process causing insulin resistance. Conversely eliminating saturated and trans fats from the diet enables the mitochondria to work properly. Yet more saturated fat-mediated inflammation occurs via the key gene transcription factor, nuclear factor kappa beta (NF-kappa B) which drives the inflammatory responses of the innate immune system. It has been shown that saturated fats can bind to toll-like receptors (TLR-4) and thus cause indirect activation of NF-kappa B (Suganami et al. 2000; Lee et al. 2004; Kennedy et al. 2009; Sears & Ricordi 2011). Once activated, this causes the release of gene products such as COX-2 enzymes and inflammatory cytokines such as tumour necrosis factor alpha (TNFalpha), interleukin-1 and interleukin-6. Epidemiological data is congruent with this evidence: consumption of diets rich in saturated fatty acids is highly correlated with metabolic syndrome (Cnop 2008; Galgani et al. 2008; Johnson et al. 2008). The authors of the review conclude that reducing the consumption of foods rich in saturated fatty acids, substituting with oils containing oleic acid or n-3 fatty acid, and increasing the consumption of whole grains, fruits and vegetables would reduce the incidence of metabolic disease. As a typical Western diet (of 2000 kcal/day) contains 27.7 g of saturated fat (USDA 2007), higher than the recommended maximum of 22 g/day, this is of great concern for population health. This is even more alarming when examining HPLC diets, because the Atkins diet contains 26% or 43 g of saturated fat/day if consuming a typical intake of 1500 kcal (58 g of saturated fat if consuming 2000 kcal/day). Considering the above evidence, such diets high in saturated fats would lead to extensive inflammation and insulin resistance, leading to metabolic syndrome, despite any weight loss. In order to prevent diabetes and metabolic syndrome, and also to reverse the diseases once established, it is essential to eliminate intracellular fats. How is it possible to

minimise fat accumulation in muscle cells? One way to reduce intracellular lipid is through bariatric surgery. A study on insulin resistant obese subjects found that post gastric bypass surgery, due to the reduction in fat digestion, there was a rapid decrease in triglyceridaemia and circulating fatty acids concentrations (Greco et al. 2002). This resulted in the complete elimination of ectopic lipids in muscle tissue, as confirmed by muscle biopsies. Insulin sensitivity was normalised, despite remaining obese (in six months the BMIs reduced from 51 to 39). A less drastic alternative to surgery to reduce intracellular lipid is to consume a very low fat diet. For example, a long term study in rats found that the lower the carbohydrate content and the higher the fat content of the diet, the worse the degree of glucose tolerance, as measured by the area under the curve after an oral glucose tolerance test (OGGT) (Kaneko et al. 2000). Rats were fed isocaloric amounts of food, with the same protein content of 15%, but differing in carbohydrate and fat content. The results after 40 weeks are listed in Table 4.5. Table 4.5. Rat study on weight gain and biochemical parameters with diets of different macronutrient compositions, after 40 weeks 20% c;65% f 40% c;45% f Body weight Plasma fatty acids Insulin secretion Glucose tolerance

++++ ++++ ++++ impaired +++

+++ +++ +++ impaired ++

60% c;25% f ++ ++ ++ normal

80% c;5% f + + + normal

c â&#x20AC;&#x201C; carbohydrate f â&#x20AC;&#x201C; fat Thus not only did the low-carbohydrate high-fat diet cause the most weight gain, despite equal calorie content, it also caused the highest insulin secretion and the worst glucose intolerance. Human research also shows that a low saturated fat diet can achieve improved insulin sensitivity. In a case-control study, intramyocellular lipid in the soleus muscle was 31% lower in a group of vegans compared with meat eaters, matched in age and BMI (Goff et al. 2005). This would suggest that a low saturated fat diet, as in a typical vegan diet, reduces intracellular lipid concentration and hence improves insulin sensitivity. In addition to a high fat diet, ketone bodies also induce insulin resistance, as discussed earlier. One of the mechanisms is that acetacetate lowers cellular levels of insulin receptors by changing the cell surface expression (Yokoo et al 2003). This process begins within 6 hours of a ketotic state, and by 24 hours insulin binding is reduced by 38% due to this retardation in cell surface functional insulin receptor synthesis. Thus a typical high-fat, ketotic HPLC diet can rapidly induce insulin resistance due to this dual mechanism.

Lipotoxicity Recent research has revealed that excess free fatty acids cause lipoapoptosis, the process of lipid-induced programmed cell death: if excess lipids are present, eventually the detoxification and storage pathways become saturated, there is cellular dysfunction and cell death results. This is a particular problem in patients with abdominal obesity, because their subcutaneous adipose tissue has become saturated, and visceral adiposity and ectopic adiposity results: storage of triglycerides outside of adipocytes. These ectopic lipids infiltrate the heart, liver, beta pancreatic and muscle cells, and the process of lipotoxicity ensues. Lipotoxicity has a central role in the development of metabolic syndrome, as infiltration of myocytes (as mentioned earlier) means that they cannot accept glucose any more, and insulin resistance ensues with hyperglycaemia. Furthermore, when beta pancreatic cells become saturated with free fatty acids, apoptosis occurs and the pancreas cannot produce sufficient insulin, contributing even further to the pathology of type 2 diabetes (Unger et al. 2001; 2009). Infiltration of the liver with free fatty acids (hepatic steatosis or “fatty liver”) causes an excess of triglyceride-loaded VLDL cholesterol to be released. As insulin resistance inhibits the enzyme lipoprotein lipase, this VLDL cholesterol is not broken down quickly, and exchanges its triglyceride with cholesterol from LDL cholesterol and HDL cholesterol. The resulting triglyceride-loaded LDL cholesterol deposits the triglyceride in the liver, leaving behind the remaining small dense LDL cholesterol, which is deadly as it is more readily oxidised and therefore more atherogenic. This process is enhanced by the process of free fatty acids causing apoptosis in both the coronary artery endothelial cells and also the cardiomyoctyes, further leading to heart disease (ASO/ICCR 2010). It is not just adipocytes themselves which are a source of these damaging free fatty acids: the diet plays an important part too. The main culprits are saturated fat, cholesterol and the omega 6 fatty acid arachidonic acid. In patients who suffer from abdominal obesity, they are well on the way to developing metabolic syndrome, and they cannot afford to ingest extra fat, as their own “metabolic sink” is saturated, and circulating free fatty acids will end up infiltrating organs and muscles as described above. Furthermore, simply being obese leads to the body producing excess cholesterol. For example, studies (Schaffer 2003) have shown that the saturated fat palmitic acid (found in butter, pork, beef, lamb, eggs, chocolate and palm oil) causes apoptosis in the cororanary artery endothelial cells and also the cardiomyocytes, leading to heart disease. In addition, palmitic acid causes apoptosis in the beta cells of the pancreas, leading to diabetes, and also acts on muscles to cause insulin resistance. In the liver, palmitic acid induces hepatocyte cell death, resulting in hepatic steatosis. Free cholesterol when present in excess has been shown to be proapoptopic in macrophages, and therefore has a significant role during the progression of atheromatous plaques. Lipoapoptosis from surplus fatty acids also induces apoptosis in lymphocytes, thus contributing to immune deficiencies, and in neuronal cells this process is significant in the development of neurodegenerative diseases.

Obesity management specialists should be telling their patients to reduce their fatty acid intake by following a low-fat diet (10-20%), much lower than in HPLC diets, because those with abdominal obesity will not have any further storage capacity in their subcutaneous adipose tissue, and are at serious risk of increasing their dangerous metabolically active visceral adipose tissue with any consumption of dietary fat. Trans fats Butter, cheese, milk, beef and lamb also contain some trans fats, as these are formed by bacteria in the lining of ruminants' stomachs (Murray & Flagel 2005). Trans fats are even more deadly than saturated fats, as they are even more atherogenic: between 2.5 and at least 10 times more (Stender et al. 2004). Trans fats also make cell membranes more rigid, thus interfering with receptor signaling and transmission. A consequence is insulin resistance, as the insulin molecule cannot change the composition of the membrane for correct signaling. They also impair the synthesis of EPA and DHA by inhibiting delta-6desaturase, and are toxic. This is one reason why olive oil should be the only oil (apart from macadamia nut oil) ever used for cooking, as it is the only oil that does not convert massively to trans fats on heating (and only then if kept below 180 degrees centigrade; Mouton 2006). Arachidonic acid What other constituents of meat and dairy are dangerous to health? All animal protein sources including meat, chicken, turkey, eggs, fish and calamari contain arachidonic acid, a polyunsaturated long chain omega 6 fat. Like trans fats, this makes membranes less fluid, contributing to high blood pressure and insulin resistance. In addition, arachidonic acid is converted into pro-inflammatory eicosanoids such as the pro-inflammatory prostaglandins (e.g. PGE2, PGF2, PGD2, PGI2), thromboxanes and pro-inflammatory 4 series leukotienes (e.g. LTA4). These inflammatory eicosanoids cause internal silent inflammation within the fat and muscle cells, interrupting the flow of glucose into the cells, thus contributing to insulin resistance and metabolic syndrome (Sears & Ricordi 2011). The increase in inflammation also accelerates chronic diseases such as high blood pressure, thrombosis, vasospasm, allergic reactions, and arthritis. Chronic silent inflammation, particularly that involving the key gene transcription factor that drives the inflammatory responses of the innate immune system, nuclear factor kappa beta (NFkappa B), has also been implicated in the role of the development of cancer (Dolcet et al. 2005). Furthermore, arachidonic acid has been shown to have a direct effect on the activation of NF-kappa B (Ramakers et al. 2007). How do we prevent this chronic inflammation from occurring? Losing weight in order to lose visceral fat helps, and we can take anti-inflammatory drugs. These work by inhibiting the enzymes that convert arachidonic acid into pro-inflammatory eicosanoids or inhibiting the release of arachidonic acid in the membrane. It has long been known

about the protective effect of aspirin against heart disease, and even as far back as 1991, research showed that a daily dose of aspirin significantly reduced the risk of bowel cancer (Thun & Namboodiri 1991). However, even better than taking medication would be the prevention of the inflammation in the first place: a medical diet which aims to be antiinflammatory in action. The dietary nutrients that induce inflammatory responses via the NF-kappa B system are saturated fat and arachidonic acid. Thus an anti-inflammatory diet would ideally eliminate the intake of arachidonic acid containing food such as meat, fish and egg yolk, (thus also reducing the saturated fat content) and in addition reduce omega 6 rich sources such as sunflower and safflower oil, which can be converted into arachidonic acid. Polyunsaturated/monosaturated to saturated fat ratio A typical Western diet has a very poor polyunsaturated (PUFA) to saturated fat (SFA) ratio of 0.4/1, and a very poor monosaturated (MUFA) to SFA ratio of 1.5/1. (The ratio should reflect as little saturated fat as possible, as it is only detrimental to health). Research indicates that replacing saturated fat with unsaturated fat is an effective way to lower cholesterol levels (Hu et al. 2001). Additionally, individuals with diabetes who consume less than 0.4/1 PUFAs/SFAs are 3.4-8.2 times more at risk of developing diabetic complications (Diabetes, Nutrition and Complications Trial 2006). This study also found that diabetics who consume less than 1.5/1 monosaturated fat/saturated fat are 3.6-4.7 times more likely to develop diabetes complications. One way of reducing the amount of saturated fat in the diet is to substitute nuts for animal products, as nuts provide valuable sources protein, unsaturated fat, monosaturated fat (e.g. almonds and hazelnuts) and n-3 fatty acids (walnuts). Evidence from numerous nut studies show that nuts lower serum cholesterol (Table 4.6). The effect is cumulative. Thus eating for example 4 walnuts and 7 g of almonds a day would result in a lowering of LDL cholesterol by 5%. This beneficial effect is confirmed in epidemiological studies which demonstrate that the consumption of nuts lowers the risk of cardiovascular disease (Kelly et al. 2006). Data from the Adventists' Health Study reveal that the consumption of nuts 5 or more times a week causes a reduction in ischaemic heart disease by 50% compared with consumption less than once a week (Fraser 1997). Table 4.6. The amount of nuts needed to lower LDL-cholesterol by 1% g per day walnuts 4 (=1 small walnut) peanuts 4 pistachios 4 almonds 7 macadamias 10 pecans 11

(Almario et al. 1994) (O'Byrne et al. 1997) (Edwards et al. 1999) (Jenkins et al. 2002; Sabate et al. 2003) (Curb et al. 2000) (Rajaram et al. 2001)

Eating nuts not only reduces cholesterol, but also improves glycaemic control in type 2 diabetics. One study compared supplementation of 475 kcal of mixed nuts (75 g) with supplementation of 475 kcal of wholewheat no-added sugar muffins to a traditional diabetic diet (Jenkins et al. 2011). The protein content was the same. After 3 months, the cholesterol was 0.24 mmol/l lower and LDL cholesterol was 0.22 mmol/l lower in the nut group compared with the muffin group. Furthermore, the HbA1c was 0.21% lower in the nut group. The additional nut calories did not result in any weight gain. If one wished to pursue an HPLC diet, as nuts have a low-carbohydrate content, it makes sense to use nuts as a protein source rather than saturated fat-containing animal foods. Omega 6 to omega 3 ratio Another unfavourable feature of eggs, apart from their saturated fat and arachidonic acid content, is a poor ratio of omega 6 to omega 3 fatty acids. With supermarket eggs this is 19.4/1. An excess of omega 6 acids inhibits the action of delta-6-desaturase, thus limiting the formation of beneficial EPA and DHA. This ratio improves, the more free range and organic the hen (Greek farm eggs have a ratio of 1.3/1) (Mouton 2006). As a typical Western diet overall has a very poor omega 6 to omega 3 fatty acid ratio of around 15/1 (the aim for health is to achieve a ratio as close to 1/1 as possible), this is one reason why it is questionable to consume large quantities of eggs, as advised in HPLC diets. Cholesterol It should also be noted that one egg contains 225 mg of cholesterol, and the recommended maximum daily intake for cholesterol is 300mg (NICE 2010; American Heart Association 2006). Although saturated fat has a greater cholesterol-raising power than dietary cholesterol, the Institute of Medicine recommends no cholesterol at all, as it is made in the body, and there is a direct association between cholesterol intake and LDL cholesterol (Institute of Medicine 2005). The American Diabetes Association is strict on cholesterol intake too, recommending no more than 200mg a day in diabetics and those with high cholesterol (Franz et al. 2002). Looking at the macronutrient intake of HPLC diets compared with a low-fat vegetarian diet such as the Ornish diet, the daily intake of cholesterol is more than double the recommended maximum for the Atkins diet (731 mg) and over the recommended maximum for diabetics or those with raised cholesterol (221 mg for the South Beach diet; 208 mg for the Zone diet) (De Souza 2008). The low-fat Ornish diet has only 7 mg of cholesterol. The body is remarkably sensitive to dietary cholesterol. For example one study examined what would happen when individuals on an egg-free low cholesterol diet (97 mg a day), were fed one egg a day. The LDL cholesterol levels increased by 12% (Sacks et al. 1984).

Note also the Lifestyle Heart Trial quoted before, which found worsening atherosclerosis on a 30% fat diet containing 139 mg/day of cholesterol (Ornish et al. 1990;1998). Thus the recommended maximum level of cholesterol could be considered to be too high. Fat and protein content of foods compared Looking at some of the specific foods recommended in a typical HPLC diet, I have analysed the fat and protein content (Table 4.7). Table 4.7. The protein and fat content of different animal foods found in HPLC diets Protein % per calorie Fat g per 100g Grilled bacon Lamb steak Cheese Lamb chops Grilled steak Eggs Roast duck breast Roast chicken

24% 25% 25% 26% 33% 34% 54% 67%

Fat % per calorie

25g 31g 34g 29g 21g 11g 9.7g 5.4g

76% 75% 75% 74% 67% 50% 46% 33%

Most (over 60%) of this fat is saturated. It should be remembered that medically, the recommended maximum amount of saturated fat is 20 g a day. The list of animal foods found in HPLC diets can be compared with the plant foods of Table 4.8, where most of the fat is unsaturated: here we can see that all of the plant foods in Table 4.8 have a higher protein percentage than six of the foods on the HPLC list in Table 4.7. Furthermore, all of these plant foods contain a lot less fat, most of which is unsaturated. Any HPLC diet could clearly be improved by substituting its high saturated fat foods with the much healthier ones on this plant-based list. Table 4.8. The protein and fat content of different vegetarian foods Protein % Fat g per 100g per calorie Fry's vegetarian burgers 42% Quorn pieces 54% Quorn mince 62% Realeat chicken style pieces 85% baked beans 34% butter beans 31% Neal's Yard soya mince 63%

4.4g 2.6g 2.0g 1.6g 0.3g 0.5g 1.5g

Fat % per calorie 26% 23% 19% 11% 5% 5% 4%

Dietary fibre Fibre and cardiometabolic risk: cholesterol Current medical recommendations bear no resemblance to HPLC diets which not only are high in total and saturated fat, but are also depleted in important sources of fibre (whole grains, root vegetables, pulses and fruit.) Plant foods are the only source of carbohydrates and fibre, so a low-carbohydrate diet has, by definition, to be low in plant foods and fibre. Early humans consumed diets that were mainly plant-based and were therefore high in fibre and low in glycaemic load: large amounts of leafy vegetables, foliage, shoots, fruit, seeds and nuts (Milton 2000; Teaford et al. 2000). The introduction of agriculture and animal farming altered the macronutrient content, but the diet was still high in fibre with a low glycaemic load: mainly unrefined grains and vegetables. Then with the emergence of the industrial revolution 200 years ago, the diet has become increasingly processed, leading to a greatly reduced fibre content (Kendall et al. 2010). Furthermore, large scale factory farming of animals in the last 60 years has led to huge increases in the consumption of animal products, which are generally high in saturated fat and cholesterol. Due to our genetic similarities with our ape relatives, this major change in our eating habits is believed to have contributed to our chronic diseases such as cardiovascular disease and type 2 diabetes. Additionally, Westernisation of lifestyle on a global scale has been shown to lead to drastic increases in these chronic diseases (Adeghate et al. 2006). Numerous studies have shown that high-fibre diets can directly reduce the risk of developing cardiovascular disease (Pereira et al. 2004). One of the principle mechanisms is by reducing serum LDL cholesterol. High-fibre diets also reduce the risk of developing type 2 diabetes and obesity (to be discussed later), and via these mechanisms also indirectly impact on the risk of developing cardiovascular disease. Indeed, foods which lower blood cholesterol (and also improve glucose control) are those containing soluble fibre (e.g. oats, barley, pulses, fruit and vegetables), and in particular soya products (Sirtori et al. 2007). For example 25 g of soya protein a day is proven to lower cholesterol, according to the UK Government's Joint Health Claims Initiative (JHCI 2002). In fact the amount of soya protein needed to lower cholesterol is actually less than this: only 16 g a day. A study examining the effect of the consumption of 500 ml of soya milk a day (equivalent to 16 g of soya protein) for 21 days, in healthy volunteers with normal cholesterol levels, found that atherogenic cholesterol levels were significantly lowered, compared to drinking no soya milk: total cholesterol was reduced by 11%, and LDL cholesterol reduced by 25%. Furthermore, HDL cholesterol (â&#x20AC;&#x153;goodâ&#x20AC;? cholesterol) was increased by 20% (Onuegbu et al. 2011). The overwhelming evidence for the cholesterol-lowering effect of fibre has led to the Adult Treatment Panel III of the National Cholesterol Education Programme recommending the increased intake of viscous fibres (soluble fibre) (NCEP 2001). In addition the United States Food and Drug Administration has approved the health claim that viscous fibres reduce the risk of coronary heart disease: beta glucan from oats and

barley (3 g/day), and psyllium (7 g/day) (US-FDA 2001). Commercial brands of porridge oats in individual portions of 29 g are a popular breakfast choice at only 99 calories, but each provide 1 g of beta glucan. Thus it is sensible to recommend porridge for breakfast on any diet in order to obtain a valuable source of this soluble fibre. A study, aimed at maximally lowering cholesterol, created a diet as similar as possible to our ancestral diet, the so called “Simian Diet”. It consisted of green leafy vegetables, fruit and nuts, equating to an astonishing 143 g/day of fibre. There were significant reductions in LDL cholesterol after only 2 weeks, compared with a low saturated fat therapeutic diet of 26 g of fibre a day. (Jenkins et al., 2001). However the diet was not practical as it involved having to ingest 5.5 kg of food every day in order to maintain weight, so another “Portfolio Diet” was devised: 8.2 g viscous fibres per 1000 kcal from oats, barley and psyllium; 22.7 g soya protein per 1000 kcal; 1 g of plant sterols per 1000 kcal; and 14 g per 1000 kcal of nuts (almonds). It was vegetarian, and also very low in saturated fat and cholesterol. After 4 weeks, not only did the LDL cholesterol reduce by 28-35% (Jenkins 2003a), this was comparable to taking a starting dose of lovastatin (Jenkins et al. 2003b). Long-term studies have looked at the portfolio approach, and found that despite decreased compliance with the diet, LDL cholesterol still reduced by 13.8% after 6 months, compared with only -3% on a low saturated fat diet (Jenkins et al. 2011), and reduced by 14.6% after one year (Jenkins et al. 2006). A review of studies on dietary ways to lower cholesterol confirmed these results, and concluded that a plant-based diet including soluble fibre, soya and nuts can reduce LDL cholesterol by 25-30%: the same degree of improvement as the effect of statins (Ferdowsian & Bernard 2009). HPLC diets, deficient in insoluble and soluble fibre (only around 10 g/day of fibre), are missing out on the opportunity to naturally lower cholesterol, and have actually been shown to increase cholesterol as mentioned before, and hence increase the risk of cardiovascular disease. The mechanism for the cholesterol-lowering effect of soluble fibre is summarised here, based on a comprehensive review (El Khoury et al. 2012): soluble fibre causes increased secretion of bile acids and their elimination (necessitating the liver to synthesise more bile acids from circulating cholesterol); the increased activity of cholesterol 7 alphahydrolase, which causes cholesterol elimination; decreased absorption of dietary cholesterol and long chain fatty acids; and fermentation products, short chain fatty acids, suppressing cholesterol synthesis. Soluble fibre also lowers triglycerides by delaying the absorption of triglycerides and glucose in the small intestine, and by inhibiting hepatic lipogenesis via down regulation of the genes involved in lipid transport and synthesis. It is not just soluble fibre which confers cardiometabolic benefits: insoluble fibre such as in wheat, rye, rice, other whole grain cereals, nuts and some legumes has been found in cohort studies to be inversely associated with the risk of developing heart disease (Liu et al. 2002; Djousse et al. 2007; Kendall et al. 2010). Furthermore, foods containing insoluble fibre have other functions. For example they act as "nature's broom" and

prevent constipation. Lack of fibre intake may increase the risk of diverticular diseases (Korzenik 2006). Other health benefits include protecting against irritable bowel syndrome, Crohn's disease and colorectal cancer (to be discussed later). Fibre and cardiometabolic risk: insulin resistance and diabetes Diabetes and insulin resistance are very important risk factors in the development of cardiovascular disease. One of the key messages from the International Chair on Cardiometabolic Risk is that if the following five factors were adhered to, there would by no type 2 diabetes at all: eating a low-fat diet, eating a low saturated fat diet, increasing fibre intake, maintaining a normal BMI, and increasing physical activity (ASO/ICCR 2010). I have already outlined how saturated fat intake is linked to insulin resistance via inflammatory pathways and lipotoxicity (its role in the development of fatty liver will be addressed later), so I would now like to examine the protective role of fibre in insulin resistance and diabetes: research demonstrates that fibre intake is inversely associated with insulin resistance (Schulze et al. 2007) and diabetes (Erkkila & Lichtenstsin 2006). Diets rich in fibre improve glycaemic control in type 2 diabetics (Brennan 2005). Thus the greater the intake of high-fibre, whole grain foods with a low GI, the lower the incidence of metabolic syndrome and insulin resistance. Which sources of fibre are good for reducing the risk of insulin resistance? (It should be noted that animal foods contain no carbohydrate and therefore no fibre at all). Research shows that a diet rich in vegetables and whole fruits leads to decreased rates of type 2 diabetes (Carter et al. 2010). (Note that drinking fruit juice actually increases the risk (Bazzano et al. 2008)). Soluble fibre is particularly effective in attenuating factors in metabolic syndrome. For example, a daily intake of at least 5 g of soluble fibre, particularly from whole grain foods and fruits, reduced the presence of metabolic syndrome in patients with type 2 diabetes by 54% (Steemburgo et al. 2009). (One would have to consume 125 g of oats or 34 g of oat bran to obtain 5 g of soluble fibre: not allowed on an HPLC diet). One study found that eating 2 extra servings of whole grains a day reduced the risk of diabetes by 21% (Munter et al. 2007). People consuming 3 servings of whole grains a day are 20 to 30% less likely to develop type 2 diabetes than those who consume less than 3 servings a week (Venn et al. 2004). Other research demonstrated that those eating the most whole grain cereals reduced their risk of diabetes by 61% compared with those who ate the least (Montonen et al. 2003). Furthermore, increased whole grain intake over a 6 week period also reduces blood glucose, fasting insulin and evidence of insulin resistance in obese, insulin-resistant subjects (Pereira et al. 2002). One study performed repeated measurements of blood glucose, insulin, cholesterol and waist circumference on 2,875 healthy volunteers to analyse the correlation with dietary patterns (Liu et al. 2009). The results showed that refined grains, cakes, biscuits, sweets, sugary soft drinks and high-fat dairy all promoted insulin resistance, whereas a diet based on whole plant foods protected against insulin resistance.

Additionally, cereal fibre consumption drastically reduces the risk of developing both coronary heart disease and type 2 diabetes, and reduces markers of systemic inflammation (Liu et al. 2003; Jenkins et al. 2003; Jensen 2004; Qi et al. 2006). One of the mechanisms for this is that cereal fibre is known to increase adiponectin levels: high adiponectin levels are associated with improved glycaemic control, insulin sensitivity, a favourable lipid profile and reduced inflammation (Mantzoros et al. 2005). For example, cereal fibre in the highest quintile of intake is associated with 19% higher adiponectin concentrations than those with the lowest quintile of intake (Qi et al. 2005). With reference to weight loss, diets rich in fibre have a positive effect on long-term weight management (Slavin 2005). Overwhelming evidence for the importance of eating a plentiful supply of cereal fibre comes from a large prospective cohort study looking at mortality statistics and fibre consumption (Park et al. 2011). 31,456 deaths were examined over 9 years, and it was reported that dietary fibre from grains, but not from other sources, was significantly inversely related to total and cause-specific death rates. The highest quintile of fibre intake was associated with a 22% reduced risk of death from all causes, with mortality from cardiovascular, respiratory and infectious disease being reduced by 24%-56% in men, and by 34%-69% in women. There was also an inverse relation between cancer deaths and fibre intake in men. Careful control for confounding variables added to the validity of the results. The authors speculated that the reduced mortality was linked to the antioxidant and anti-inflammatory properties of the whole grain components. Traditional HPLC diets specifically ban or greatly limit whole grain consumption, and can therefore be regarded as increasing mortality risk. Meat and milk and type 2 diabetes What dietary factors increase the risk of developing type 2 diabetes? Evidence demonstrates that there is a strong link between eating red and processed meat and developing type 2 diabetes (Vang et al. 2008). This study followed 8,000 Seventh Day Adventists over 17 years, and found that eating meat at least once a week resulted in a 74% increase in the risk of developing type 2 diabetes, compared with being vegetarian. Some of this increased risk was due to there being a higher risk of being overweight in the meat eaters, but once BMI was controlled for, the increased risk was still as high as 38%. Another study found that eating two servings of red meat a day increased the risk of metabolic syndrome by 26% (Lutsey et al. 2008). This was backed up by a further study reporting that individuals consuming the highest quartile of red meat had a 2.7 times higher risk of metabolic syndrome compared with the lowest quartile. There was also an 8.1 times higher risk of central obesity in the high meat group (Babio et al. 2010). One systematic review and meta-analysis of 12 cohort studies found that the risk of diabetes increased by 17% for total meat, 21% for red meat and 41% for processed meat consumption, comparing the highest to lowest quartiles (Aune et al. 2009). BMI, smoking

and physical activity were controlled for. Another meta-analysis of 3 cohort studies reported that eating 50 g of processed meat a day increased the risk of diabetes by 51%, even after controlling for age, BMI and lifestyle factors (Pan et al. 2011). From the above evidence it is apparent that any diet including meat is associated with a higher risk of diabetes and metabolic syndrome. This has great relevance to traditional HPLC diets, in which the commonest source of protein is meat (de Souza et al. 2008). Proof of this comes from a study which looked at low-carbohydrate diets, and found that diabetes risk was increased by 37% if there was a high animal protein and animal fat intake. The most important risk factor was the consumption of red and processed meat. Conversely, the low-carbohydrate diets containing mainly vegetable protein and vegetable fat actually had a reduced risk of diabetes by 22% (de Koning et al. 2011). This was despite controlling for smoking, exercise, body mass index, family history, and coffee and alcohol intake. The authors state: â&#x20AC;&#x153;Red and processed meat contains several components that may elevate type 2 diabetes risk.â&#x20AC;? The Aune et al. and de Koning et al. papers discuss the mechanisms for the link between meat consumption and diabetes risk. These are summarised below: Meat consumption is associated with: 1. Overweight and obesity: consumption of red meat, sausages and hamburgers are all significantly dose-response associated with a higher risk of weight gain (Bes-Rastrallo et al. 2006). In fact, it has been repeatedly confirmed that red meat intake is positively associated with future risk of weight gain (Mozaffarian et al. 2011; Verngaud et al. 2010). 2. The metabolic syndrome (Azadbakht & Esmaillzadeh 2009; Babio et al. 2010) 3. Hyperinsulinaemia and hyperglycaemia (Aune et al. 2009). 4. Haem-iron promoting oxidative stress and free radicals, causing damage to pancreatic beta cells (Wolf 1993), and interfering with glucose metabolism and reducing pancreatic insulin synthesis and secretion. Iron deposition in muscle and liver may cause focal tissue damage, which disrupts insulin signaling. There is a strong correlation between haem iron intake and diabetes (Rajpathak et al. 2009), as reported in the Iowa Women's Health Study (Lee et al. 2004), and the Nurses' Health Study (Rajpathak et al. 2006). 5. Impaired glucose metabolism (Papakonstantinou et al. 2005). 6. Nitrosamine formation from the ingestion of nitrites and nitrates in processed meats causing toxicity to pancreatic beta cells, thus increasing the risk of type 1 (Sipetic et al. 2005) and 2 diabetes (Ito et al. 2009). Nitrosamines have a diabetogenic effect on adult rats (Portah et al. 1980), and rat pups (Tong et al. 2009), triggering pancreatic islet hypertrophy, hyperglycaemia, and hypersinsulinaemia. Blood nitrite concentrations are higher in adults with glucose intolerance and type 2 diabetes (Pereira et al. 2008).

7. The production of toxic advanced glycation end-products (AGEs), thus triggering the inflammation associated with metabolic syndrome and cardiovascular disease (to be discussed later) (Peppa et al. 2002). AGEs inhibit glucose-stimulated insulin secretion (Zhao et al. 2009). Conversely, restricted intake of AGEs is associated with improved insulin sensitivity in mice (Hofman et al. 2002). 8. Increased levels of inflammatory mediators, such as C-reactive protein, which is associated with the metabolic syndrome (Azdbakht & Esmaillzadeh 2009). 9. Gamma-glutamyltransferase (GGT) (Lee et al. 2004). This is a marker of oxidative stress, and is associated not only with alcohol, but also with red meat intake. It is a strong predictor of both diabetes and hypertension, with associations with other cardiovascular disease risk factors such as raised LDL cholesterol and triglycerides. It has a role in counteracting oxidative stress, but also produces oxidative stress itself, via free radical production, especially in the presence of iron. Even levels at the high end of normal are associated with a greater mortality. Conversely fruit has an inverse correlation with GGT. 10. Lower levels of adiponectin (Zyriax et al. 2008). Adiponectin is a hormone secreted from adipose cells, with anti-diabetic, anti-obesity and anti-atherosclerosis actions on glucose and lipid metabolism and endothelial cells: it increases insulin sensitivity, increases glucose uptake, decreases gluconeogenesis, increases lipid catabolism, enhances weight loss, and protects against endothelial dysfunction. In other words, it suppresses the metabolic pathology associated with metabolic syndrome. Adiponectin levels are reduced with meat intake, but increased with fruit and vegetable intake. 11. Consuming a diet high in animal-derived saturated fatty acids as opposed to plantderived cis-unsaturated: such individuals have greater insulin resistance and glucose intolerance (Summers et al. 2002). 12. Higher proportions of saturated fatty acids as opposed to cis-unsaturated fatty acids in serum cholesterol esters and phospholipids: such individuals have greater insulin resistance and a higher risk for type 2 diabetes (Hodge et al. 2007; Vessby et al. 1994; Riserus et al. 2009). Although incompletely understood, the mechanisms responsible may involve changes in cell membrane ďŹ&#x201A;uidity, glucose transporter function, and gene expression (Riserus et al. 2009). Animal protein from dairy products is also associated with an increased risk of insulin resistance. The International Chair on Cardiometabolic Risk highlights research illustrating that avoiding milk is associated with a reduced risk of insulin resistance: increased milk consumption is associated with an increase of metabolic syndrome (Lawler et al. 2005). Type 1 diabetes is also affected by diet: a study of children from 40 different countries showed that the more meat and milk they ate, the higher the risk of diabetes, contrasting with the more plant foods they ate, the lower the risk (Muntoni et al. 2000). Many studies have found that milk products produce high insulin responses,

despite their low glycaemic index (Holt et al. 1997; Ostman et al. 2001). The whey fraction of milk proteins has the strongest insulinotropic properties (Nilsson et al. 2004). Conversely, the incidence of metabolic syndrome is much lower in vegetarians compared with meat-eaters, and is associated with significantly lower values for metabolic risk factors (Rizzo et al. 2011): the risk of metabolic syndrome in vegetarians was 56% lower than in non-vegetarians, and this was associated with lower values for triglycerides, blood glucose, blood pressure and waist circumference, even after controlling for lifestyle and demographic factors. These results can be partly explained by vegetarians tending to consume a high proportion of plant foods, which are naturally high in fibre compared with animal foods which contain none; plant foods are low in saturated fat; and vegetarians have lower BMIs (Craig 2010). It has been estimated that replacing red meat with wholegrains would result in a 25% lower risk of diabetes and replacing processed meat with wholegrains would result in a 35% lower risk of diabetes. Replacing red meat and processed meat with nuts would result, respectively, in a 20% and 32% lower risk of diabetes (Pan et al 2011). Glycaemic index and diabetes risk Low GI/GL diets have been assessed in the terms of the prevention and treatment of diabetes, as the main objective in the treatment of diabetes is the regulation of blood glucose levels. Pooled results of numerous epidemiological studies indicate that low GI/GL diets are protective against type 2 diabetes: there was a 40% increase in the risk of type 2 diabetes with the highest GI quintile versus the lowest (Barclay et al. 2008). Such diets have also been used therapeutically in type 1 and 2 diabetics, and have been shown to improve HbA1c levels (Kendall et al. 2006). For example a meta-analysis of 14 longterm randomised controlled trials demonstrated that HbA1c levels were reduced by an average of 7.4% in comparison to high GI diets (Brand-Miller et al. 2003). A 1% reduction in HbA1c level corresponds to a 21% risk reduction in complications and deaths related to diabetes (Stratton et al. 2000). Thus high-fibre/low GI diets are highly desirable in any overweight patient at risk from insulin resistance and diabetes, or already diagnosed as such. Indeed the British Diabetes Association and numerous other agencies have all recommended increasing dietary fibre in individuals with type 2 diabetes (Anderson et al. 2004): â&#x20AC;&#x153;We recommend that the diabetic individual should be encouraged to achieve and maintain a desirable body weight and that the diet should provide these percentages of nutrients: carbohydrate, equal or more than 55%; protein, 12-16%; fat, less than 30%; and monosaturated fat, 12-15%. The diet should provide 2550 g/day of dietary fibre (15-25 g/1000 kcal)â&#x20AC;?. Low-carbohydrate diets, by definition, are also low in fibre, so will provide none of the benefits discussed here. With relevance to HPLC diets, which state that one of the main objectives is to control glycaemia, a study was conducted in subjects with impaired glucose tolerance, comparing diets with different types of carbohydrate. After 4 months, mean plasma glucose concentrations over 8 hours were lowered by the same amounts on a low-carbohydrate, high-monosaturated fat diet as a high-carbohydrate, low-glycaemic index diet, compared

with a high-carbohydrate, high-glycaemic index diet (Wolever & Mehling 2003). This indicates that it is not necessary to limit carbohydrates to reduce postprandial plasma glucose, as all that is required is to lower the GI value of the carbohydrates. In this way the valuable nutrients, vitamins, minerals and fibre contained in low GI carbohydrates are not restricted, as occurs on low-carbohydrate diets. Indeed, the American Diabetic Association states that diets should contain no less than 45% of carbohydrate (Sheard et al. 2004): “Low-carbohydrate diets are not recommended in the management of diabetes. Although dietary carbohydrate is the major contributor to postprandial glucose concentration, it is an important source of energy, water-soluble vitamins and minerals, and fibre. Thus, in agreement with the National Academy of Science-Food and Nutrition Board, a recommended range of carbohydrate intake is 45-65% of total calories. In addition, because the brain and central nervous system have an absolute requirement for glucose as an energy source, restricting total carbohydrate to less than 130 g/day is not recommended.” In the assessment of the role of low GI/GL diets in body weight regulation, the benefits are less clear. Scientific reviews arguing the case for and against low GI/GL diets in obesity have already been discussed. Early research documents hypoglycaemic symptoms in only 3 days on a lowcarbohydrate diet following an oral glucose tolerance test (Permutt et al. 1976). This is supported by several cases reported in the British Medical Journal: individuals who followed self-imposed low-carbohydrate diets, developed a reactive hypoglycaemia on consumption of any meals containing carbohydrate (leading to dizziness, weakness, nausea, palpitations, abdominal pain, myalgia and fatigue). The glucose levels were as high as 12.7 mmol/litre at 2 hours following an oral glucose tolerance text and as low as 1.5 mmol/litre at 3 hours. “Carbohydrate restriction is known to cause abnormalities of glucose handling, and an abnormal rise in the blood glucose concentration after glucose challenge is well reported in people on low-carbohydrate diets. Subsequent changes in insulin and fatty acid mobilisation may then result in reactive hypoglycaemia.” The only treatment for these patients with diet-induced symptomatic hypoglycaemia was to ingest regular small amounts of carbohydrate throughout the day, over several weeks, to reduce their hyper secretion of insulin in response to carbohydrates (Bethune et al. 1999). The effects are similar to those seen in starvation, the so called “starvation diabetes” (Tzagournis et al. 1970). There is now abundant evidence that high-protein diets have detrimental effects on glucose homeostasis by promoting insulin resistance and increasing gluconeogenesis (Tremblay et al. 2007). When high carbohydrate ingestion halts ketogenesis, subsequent amino acid and glucose ingestion will produce a higher insulin release which can last for days (de Menezes et al. 2010): the result of HPLC diets is an over-stimulation of insulin following ingestion of carbohydrates or certain amino acids, and hence lowered insulin sensitivity. For example, it has been shown that a short-term moderate increase of protein

intake, from 50 g to 82 g a day results in an increase of insulin secretion after only 4 days (Remer et al. 1996). Long-term high-protein intake has also been studied: researchers examined the effect on insulin, plasma glucose and glucagon of high-protein intake over 6 months. The researchers compared a high intake of protein (1.87 g/kg/day), similar to a typical HPLC diet, with a normal intake of protein (0.74 g/kg/day) (Linn et al. 2000). In comparison to the normal protein diets, the high-protein diets caused an increase in glucose-stimulated insulin secretion of 69%. This was due to a reduced glucose threshold of the beta cells. Overall glucose disposal was decreased by 12%, indicating a lowered insulin sensitivity. They also documented an increase in fasting glucagon of 34%, resulting in a higher hepatic glucose output, and an increase in gluconeogenesis of 43%. These findings supported the authors' previous research where the conclusion was that high-protein diets accelerate the loss of insulin secretion in type 1 diabetics, thus promoting diabetes: highprotein diets can actually make diabetic patients more insulin resistant, with subsequent increased demand on the pancreatic beta cells and their ultimate destruction. The researchers concluded â&#x20AC;&#x153;In general, high protein ingestion could be more detrimental in clinical situations with impaired glucose tolerance than is recognised: there is evidence that high protein intake promotes diabetes... The protein supplied by a meal is a major stimulator of insulin secretion.â&#x20AC;? (Linn et al. 2000). Population studies mirror these results, reporting that even after controlling for BMI, total energy intake and exercise, low starch and low fibre intake is associated with insulin resistance and hyperinsulinaemia, and that high saturated fat intake is also associated with insulin resistance and hyperinsulinaemia (Marshall et al. 1997). Rodent studies also demonstrate the effect of high protein intake on glucose homeostasis. For example two groups of rats were fed either an HPLC diet (55% protein, 15% fat, 30% carbohydrate) or an isocaloric balanced diet (27% protein, 12% fat, 61% carbohydrate) (Usami et al. 1982). After only 2 weeks, the HPLC group had significantly higher fasting glucose and insulin than the high-carbohydrate group. Furthermore, once given arginine, the insulin secretion was significantly higher in the HPLC group. Interestingly there was no difference in weight, again proving that weight loss is calorie rather than macronutrient dependent. From the above evidence one can conclude that HPLC diets interfere with normal glucose handling, simulating the effects of early diabetes, and can lead to a condition of carbohydrate intolerance requiring prompt medical attention. Treating insulin resistance through diet and glycaemic control How do we help prevent and cure diabetes (thus reducing cardiometabolic risk), through diet? One of the key mechanisms in determining the development of type 2 diabetes is the presence of a fatty liver (hepatic steatosis). If patients with type 2 diabetes are put on a low-fat diet, the fat in the liver reduces from an unhealthy 12% to a healthy 2%, and blood glucose and insulin levels decrease accordingly (ASO/ICCR 2010).

One study showed that obese non-diabetic subjects placed on a low-fat diet (16% fat; 61% carbohydrate; 19% protein) had a mean reduction in liver fat of 20% after only 2 weeks (Westerbacka et al. 2005). How could an HPLC diet such as the Atkins diet (62% fat) or South Beach diet (40% fat) reduce a fatty liver? They can only be described as high-fat diets, so would actually increase the amount of fat in the liver even more, and hence increase the risk of developing type 2 diabetes. For example, a study in rabbits compared a low-carbohydrate, high-fat diet with a normal rabbit chow diet (highcarbohydrate, low-fat) in terms of liver parameters (Birkner et al. 2005). After 24 weeks, despite no difference in weight between the two groups, the low-carbohydrate rabbits had liver steatosis on microscopy, secondary to increased synthesis of triacylglycerol in the hepatocytes. Furthermore, liver antioxidant enzyme activity was markedly increased by up to 95%, indicating high levels of inflammatory reactive oxygen species, which are an important factor in causing steatosis. Markers of gluconeogenesis also increased by 33%. The increase of fat in the liver and subsequent insulin resistance on low-carbohydrate diets was proved in an experiment on rats fed ketogenic low-carbohydrate, high-fat diets (Jornayvaz et al. 2010). A subsequent infusion of insulin led to severe hepatic insulin resistance, compared with the rats fed a normal chow diet, high in carbohydrates: there was no suppression of hepatic glucose production (gluconeogenesis) in the lowcarbohydrate rodents. (Insulin normally suppresses gluconeogenesis). This was associated with a 350% increase in fatty acids in the liver. Thus the obese, who already have increased fat in the liver and high rates of insulin resistance, would be subjected to even higher rates of fatty liver disease and insulin resistance on a low-carbohydrate, highfat diet. A plant-centred, high-fibre, low-animal fat diet can greatly reduce the need for medication in patients with diabetes (Jenkins et al. 2003): foods rich in complex carbohydrates such as wholemeal bread, wholewheat pasta, whole grain rice, oats and potatoes, which are all missing from HPLC diets. One study showed that of type 2 diabetics following a 10% fat vegetarian diet, 71% could stop their oral hypoglycaemic agents after only 3 weeks (Barnard RJ et al. 1994). Another study of type 2 diabetics found that a low-fat high-fibre vegan diet (i.e. with a low to medium glycaemic load) resulted in approximately twice as much greater reductions in HbA1C, LDL cholesterol and weight than an American Diabetes Association (ADA) diet. 43% were able to stop their medication after 5 months, compared with only 26% in the ADA group (Barnard et al. 2006). In one 74 week clinical trial of type 2 diabetes, a low-fat vegan diet resulted in a reduction in HbA1c by 0.41, compared with an increase in HbA1c of 0.01 on the standard ADA diet (Barnard et al. 2009a). In addition, cholesterol levels decreased by 20.4 mg/dl in the vegan group, compared with a decrease of only 6.8 mg/dl in the ADA group. Both diets resulted in weight loss, but the ADA patients were consciously cutting calories, unlike the vegan group who ate until satiated. The patients found both diets equally acceptable and easy to adhere to, proving that a low-fat vegan diet is an excellent

treatment choice: it reverses diabetes compared with only minor improvements in metabolism with a conventional diabetes diet (Barnard et al. 2009b). The presence of fibre improves glycaemia in a number of ways (Barnard 2009): it delays gastric emptying which reduces the rate of glucose absorption; it slows down the absorption of glucose into the blood stream; it is fermented in the colon producing short chain fatty acids, which inhibit glucose production in hepatocytes; and it increases satiety. The net result is promotion of weight loss and improved insulin sensitivity. One of these mechanisms is demonstrated in a study which fed cereal products with varying amounts of indigestible carbohydrates to participants as an evening meal (50 g of available starch) (Nilsson et al. 2010). The next morning the postprandial glucose response was inversely related to plasma butyrate, which was correlated with the amount of fibre eaten. Thus consuming barley kernels resulted in higher concentrations of butyrate and an improved glucose tolerance, compared with eating white bread. This mechanism is one explanation for whole grains being protective against type 2 diabetes and cardiovascular disease. How much fibre is needed to improve glycaemia in diabetics? Diets containing 45-50 g a day of fibre have been found to be effective. It is of particular importance to include soluble fibre sources (7-13 g), as not only do these improve glycaemic control, they also reduce total and LDL cholesterol, and thus further reduce cardiometabolic risk (Brown et al. 1999). Soluble fibre is found in oats, barley, pulses, fruit and vegetables. For example one study showed that if type 2 diabetics ate 50 g of fibre in the form of oats, fruit and vegetables, levels of blood glucose, insulin, triglycerides, total and LDL cholesterol and glycosylated haemoglobin were all lowered (Chandalia et al. 2000). The control group ate 24 g of fibre a day, similar to healthy eating guidelines (American Dietetic Association), so to prevent and treat diabetes, higher levels of fibre should be advised. This would be impossible on a typical HPLC diet! Furthermore, pectin, the soluble fibre found in apples and pears, has beneficial effects on delaying gastric emptying and improving glucose tolerance (Schwartz et al. 1988). This makes the HPLC mantra â&#x20AC;&#x153;avoid fruitâ&#x20AC;? even more alarming. Low glycaemic index fibre-rich foods have also been found to reduce HbA1c in type 1 diabetics (Giacco et al. 2000). The overwhelming message is that increased fibre intake improves glycaemic control, and as a typical HPLC diet contains less than 10 g of fibre a day (no whole grains or fruit allowed) it would be highly detrimental to any overweight subject with an increased waist circumference: the risk of metabolic syndrome (i.e. insulin resistance) would not diminish on such a diet. What is the epidemiological evidence regarding diet and insulin resistance? It is known that vegetarians have much lower rates of developing type 2 diabetes than nonvegetarians (Tonstad 2009). Results from the Adventist Health Study-2 cohort on 89,224 subjects, demonstrate that vegetarians are 61% less likely to develop diabetes as meateaters, and vegans 78% less likely (Fraser 2009). This is partly due to the fact that

vegetarians tend to have a lower BMI (Fraser 2009): by around 10% for vegetarians and 18% for vegans, and therefore a lower risk, but also due improved glycaemia from a lower saturated fat and lower glycaemic index food intake, and increased fibre, legume and vegetable protein intake. The American Dietetic Association backs this up, stating that vegetarians are much less likely to die from diabetes compared with meat eaters, and explains this by vegetarians' greater consumption of complex carbohydrates, and their lower BMI (Craig et al. 2009). This data is consistent with the finding mentioned earlier that vegetarians have a much lower incidence of metabolic syndrome compared with meat eaters (Rizzo et al. 2011). For example one large prospective study of Chinese women found that a high intake of legumes lowered the risk of type 2 diabetes compared with a low intake, even after adjusting for BMI and other factors. The risk was 38% lower for total legumes, and 47% lower for soya beans (Villegas 2008). These foods contain slow release carbohydrates, rich in soluble fibre, which are known to improve glycaemic control. Legumes are banned or severely restricted on HPLC diets, so individuals with a large waist circumference would be ill-advised to follow such a diet due to their need to reduce their risk factors for developing type 2 diabetes: they should be increasing their intake of pulses, not banning them. A further indication that high intakes of protein may have adverse effects can be taken from studies investigating the adoption of Westernised dietary habits in Japanese adults and schoolchildren (Takemoto et al. 2009). A higher incidence of type 2 diabetes correlated with increased animal protein and animal fat intakes, despite total energy intake being no different from controls. Complications of diabetes and diet: diabetic neuropathy and renal function Epidemiological studies have found that diabetics following a plant-based diet have a reduced risk of developing both diabetic neuropathy and diabetic renal disease, some of the most serious complications of diabetes. Furthermore a plant-based diet may actually be used to treat such conditions. One study examined the effect of a low-fat vegan diet on 21 patients with type 2 diabetes and peripheral neuropathy (Crane & Sample 1994). After only 25 days, 17 of the 21 subjects had total relief of their neuropathic leg pain, half were able to reduce their insulin doses and 5 patients were able to stop their oral hypoglycaemic medication completely. An HPLC diet, depleted in plant food and high in animal food would not be expected to have the same effect. Approximately 40% of diabetic patients have mild renal impairment (Soroka 1998). For this reason, medical consensus discourages diets with more than 16% protein in individuals with diabetes (Anderson et al. 2004). On a diet of 2000 kcal this means no more than 80 g a day of protein, and on a diet of 1500 kcal this means no more than 60 g a day. HPLC diets greatly exceed these protein limits, so would lead to worsening of kidney function in diabetics. For example the Dukan diet's “attack” phase is 59% protein, equivalent to 135 g a day! As the mean BMI for developing type 2 diabetes is only 30, many overweight patients are in a state of “pre-diabetes” and undiagnosed. An HPLC diet

would potentially be highly detrimental to the kidneys in any overweight patient. The protein levels in the maintenance phases of these diets (i.e. actually lower than the initial phases) are 35% for the Zone, 29% for the Atkins and 26% for the South Beach diet (de Souza et al. 2008). The Atkins diet contains an alarming range of 120g to 160g of protein a day, 75% of which is animal protein. It is animal protein which is particularly harmful to renal function. A diet high in animal protein may speed up the loss of renal function compared with a plant-based diet. In the Nurses' Health Study, animal protein intake was associated with loss of renal function among those with renal impairment (Knight 2003). It is of particular importance therefore to adhere to a diet which leads to less stress on the kidneys i.e. one which reduces blood flow and glomerular filtration rates (GFR). Plant-based diets are much better than animal protein diets for the prevention and treatment of diabetic kidney disease (Anderson et al. 2004), as animal protein diets actually increase renal blood flow and GFR in the order of beef, chicken, and fish. However soya protein does not have this detrimental effect (Nakamura et al. 1991; Kontessis et al. 1990). The soya protein hypothesis has been tested in several studies: substitution of soya protein for animal protein in patients with diabetic nephropathy decreases hyperfiltration and glomerular hypertension (Jenkins et al. 2003). One study reported a significant reduction in glomerular filtration rate when 55 g of soya protein daily was introduced into some diabetics' diet, in conjunction with reduced animal protein (Stephenson 2001). Diabetics with nephropathy have also been reported to suffer from less urinary protein losses when following a low-protein vegetarian diet (de Mello et al. 2006). For example one study on type 1 diabetics found a 54% decrease in fractional albumin clearance after 22 weeks on a diet where vegetable protein had replaced animal protein (Jibani et al. 1991). The leading international diabetes authorities have all published guidelines on the dietary management of diabetes. As an example, I now quote from the Australian set of physicians' guidelines on the nutritional management of diabetes: it states that the diet should be â&#x20AC;&#x153;low in saturated fat and sodium and high in fibre and low GI carbohydrates... It is important to limit the intake of saturated fat and avoid trans fats to assist with weight management, improve insulin sensitivity, and reduce blood lipids to decrease overall cardiovascular disease risk....Carbohydrate should come mainly from fibre rich fruits, vegetables, whole grains and legumes... It is generally advisable for people with diabetes to avoid high-protein diets due to possible negative effects on kidney function and a lack of evidence for long term benefits.â&#x20AC;? (Barclay et al. 2010) Examining statements from international medical organisations, and conducting metaanalyses on the evidence from numerous studies, a consensus of the guidelines for the nutritional management of diabetes has now been published (Anderson et al. 2004). I include a selection of quotes below:

“• Because of the high risk for atherosclerotic disease, optimal management of lipoproteins, blood pressure and oxidative stress is important. • Health-promoting diabetes diets emphasize whole grains, vegetables, fruits, and low glycemic index foods, and soy protein. Based on the available data, we recommend that diabetic patients consume a highcarbohydrate, high-fiber, low-fat diet... Whole grains, vegetables and fruits are an integral part of the recommended high carbohydrate, high fiber diet. Most whole grain foods are rich sources of insoluble fiber, minerals, antioxidants and other bioactive compounds. Higher intakes of whole grains are associated with protection from CHD, diabetes and, perhaps, obesity. Diabetes associations and national advisory bodies recommend intake of three servings of whole grain foods per day. The importance of whole grains with its many facets, including the germ and the potential low glycemic index value, may have to be stressed since wheat bran alone may have little effect on blood lipids or glycemic control. Many vegetables and fruits are rich sources of soluble and insoluble fiber, vitamins and minerals. Soluble fiber-rich foods, such as dry beans and whole grain oat and barley products, have important hypocholesterolemic effects.... The high-carbohydrate, high-fiber diet extensively and effectively used by Viswanathan and colleagues in Madras, India, for diabetes management has included 67% carbohydrate, 19% protein (predominantly from vegetable sources), and 14% fat with more than 25 g/1000 kcal of dietary fiber for more than 40 years... We concur with most diabetes associations that fruit intake should not be restricted. Higher fiber intakes improve glycemic control, lower serum cholesterol and LDL cholesterol levels and slightly reduce serum triglyceride values. Fiber intake also reduces risk for CHD and assists in weight management. Based on these observations, we recommend a fiber intake of 25–50 grams/day or 15–25 grams/ 1000 kcal. These levels can be readily achieved by following general nutrition guidelines for intake of these foods: whole grains, especially oats and barley; whole grain breads, cereals, and pastas; brown rice, dry beans, peas and lentils; nuts; fruits; and vegetables. The carbohydrate and fiber guidelines can readily by achieved by following consensus nutrition guidelines. A healthy diet including, for example, 1500 kcal/day from these choices: three servings of whole grains; five other servings of bread, cereal, rice and pasta; one or more serving of beans; four servings of vegetables; three servings of fruit; two servings of low-fat dairy products, two servings of protein; and three servings of fat. With inclusion of other foods not rich in fiber to reach an energy intake of 2000 kcal/day, this intake would provide approximately these amounts of nutrients: carbohydrate, 285 grams (57% of energy), 70 grams of protein (14% of energy), 65 grams of fat (29% of energy) and 42 grams of fiber (21 grams/1000 kcal)...

Our recommendations that protein provide 12â&#x20AC;&#x201C;16% of energy relate to the likelihood that excessive animal protein intake acts to sustain abnormal renal hyperfiltration that may contribute to development of diabetic nephropathy. Our clinical research indicates that substituting soy protein for animal protein significantly reduces hyperfiltration in type 1 diabetes. Teixiera and colleagues document that soy protein intake decreases albuminuria in type 2 diabetes. We suggest that reducing animal protein and increasing soy protein may have renoprotective effects at all stages of renal function... Soy protein intake has other health benefits, especially for diabetic individuals. Soy food intake improves serum lipid values, lowers CHD risk factors such as homocysteine and oxidation of LDL and decreases risk for CHD in a variety of other ways... Intake of saturated and trans-fatty acids and cholesterol has adverse effects on serum lipoproteins and should be restricted. To de-emphasize animal protein intake in favor of vegetable proteins such as soy we recommend that dietary cholesterol be restricted to less than 200 mg/day.â&#x20AC;? This dietary advice serves both in terms of the prevention of diabetes, and also improving glycaemic control in diabetes and preventing diabetes complications. The macronutrient composition bears no resemblance to HPLC diets. Advanced glycation end-products (AGEs) Advanced glycation end-products (AGEs), also known as glycotoxins, are a group of highly oxidant compounds with pathological effects, associated with many different chronic Western diseases. They are created through a nonenzymatic reaction between reducing sugars and free amino groups of proteins or lipids (glycoxidation). This reaction is also known as the Maillard or browning reaction. Normal metabolism produces AGEs, but in excess they promote oxidative stress and inflammation by binding with surface cell receptors or cross-linking body proteins, altering their structure and function. For example, hyperglycaemia in diabetics causes the glycoxidation of haemoglobin, producing glycosylated haemoglobin (HbA1C). The relevance to HPLC diets, is that they are present in uncooked animal-derived foods, and cooking results in even higher levels. Dietary AGEs are absorbed and contribute significant amounts to the body's AGE pool, correlating with both circulating AGEs and markers of oxidative stress (Uribarri et al. 2007). AGEs promote atherosclerosis (Lin et al. 2003). Their contribution to cardiovascular disease stems from their ability to cross-link collagen, inducing vascular stiffness; causing oxidative stress and inflammation through increased release of cytokines; activation of NF-kB; increasing levels of endothelial adhesion molecules, thus causing endothelial dysfunction; and altering lipids, modifying LDL cholesterol and promoting their uptake into macrophages, thus enhancing the formation of atherosclerotic foam cells (Vlassara et al. 2002). Indeed, they are thought to be a significant factor in diabetics' much greater risk of developing cardiovascular disease than the non-diabetic population.

Other pathology associated with AGEs include: diabetes and insulin resistance (Sandu et al. 2005); hypertension (Silacci 2002); kidney failure (Zheng et al. 2002); Alzheimer's disease (Munch et al. 1998); cataracts, age-related macular degeneration and diabetic retinopathy (Stitt 2005); arthritis (Verzijl et al. 2003); male erectile dysfunction (Seftel et al. 1997); and ageing (Baynes 2002). Conversely, low dietary AGE diets have been shown to prevent vascular dysfunction (Lin et al. 2002), kidney dysfunction (Zheng et al. 2002), and type 1 and 2 diabetes (Peppa 2003). They also improve insulin sensitivity (Hoffman et al. 2002), and significantly increase lifespan (Cai et al. 2008). The latter rodent study found that a low AGE diet (unadulterated mouse chow) resulted in mice living 13% longer than the mice eating a high AGE diet (mouse chow heated for 15 minutes), despite eating the same number of calories. The authors propose that the welldocumented lengthened lifespan effect of calorie restriction (typically reduced by 40%) is partly explained by less exposure to AGEs: dietary AGEs have a greater impact on lifespan than calorie restriction. This is because both groups of mice were on 40% calorie restricted diets, yet the control mice on a regular unrestricted mouse chow diet lived 3% longer than the calorie restricted high AGE diet mice. The impact in humans is significant, because the high AGE diet still contained considerably lower AGE levels than the typical Western diet. Translated into human terms, with the average UK life expectancy being 80.1 years old (World Bank 2009), and the average UK diet being rich in AGE-containing animal products, consuming a low-AGE diet would be expected to result in a life expectancy of 90.5 years: an extra 10 years of life! What foods are the highest in AGEs? Animal-derived foods high in fat and/or protein are generally AGE-rich and prone to further AGE formation during cooking. Even uncooked animal-derived foods such as cheese and butter contain large amounts of AGEs, due to the pasteurisation, extraction, purification and storing procedures. In contrast, carbohydrate rich food such as whole grain bread, rice and pasta, fruit, vegetables, beans and meat substitutes such as soya mince and veggie burgers contain much lower amounts of AGEs. A full list of AGE levels of 549 different foods is printed in an article for the American Dietetic Association (Uribarri et al. 2010). AGE content of sample foods The AGE content of different foods is listed in Table 4.9. Table 4.9. AGE content of different foods High AGE foods: Serving size (g) Bacon, fried with no oil Beef frankfurter, broiled

13 90

AGE kU/serving 11,905 10,143

Beef steak, fried with olive oil Whiting, breaded, oven fried Big Mac Chicken nuggets Turkey burger, fried Double quarter pounder w. cheese Fillet-O-Fish Beef, roasted Chicken, roasted Beef, ground, pan/cover Sausage, beef/pork, fried Tuna, broiled w vinegar dressing Chicken breast, grilled Pork chop, fried Turkey breast, roasted Salmon, broiled with olive oil Cream cheese Salmon, pan fried with olive oil Cheese, parmesan, grated Cheese, feta Trout, baked Shrimp, marinated, grilled on BBQ Cheese, brie Cheese, cheddar Tuna, canned with oil Butter Egg, fried

90 90 100 90 90 100 100 90 90 90 90 90 90 90 90 90 30 90 15 30 90 90 30 30 90 5 45

9,052 7,897 7,801 7,764 7,426 6,283 6,027 5,464 5,418 4,974 4,883 4,635 4,364 4,277 4,202 3,901 3,265 2,775 2,535 2,527 1,924 1,880 1,679 1,657 1,566 1,324 1,237

Low AGE foods: Veggie burger, grilled Beans, red kidney Pasta Soya burger, grilled Wholewheat bread, toasted Porridge Potato, boiled Wholewheat bread Apple Bran flakes Carrots Rice Banana

100 100 100 30 30 175 100 30 100 30 100 100 100

198 191 112 39 36 25 17 16 13 10 10 9 9

It should be noted that when a carbohydrate food (low AGE) is combined with cheese (high AGE), the result is a high-AGE food. For example, pizza has a value of 6,825 kU/100g serving; a toasted cheese sandwich is 4,333 kU/100g serving, and macaroni

cheese is 4,070 kU/100g serving. Also nuts can have a high AGE content when roasted. For example roasted cashew nuts have a value of 2,942 per 30g/serving. Thus careful food choices must be made to eat pure low AGE foods such as raw nuts. The striking difference between the high AGE foods and the low AGE foods in this list is that the high AGE foods all feature on HPLC diets, in abundance and often in â&#x20AC;&#x153;unlimited quantitiesâ&#x20AC;?, which would make the AGE total in the diet even higher, whereas the low AGE foods are all banned. The implications are that following HPLC diets would increase the risk of developing chronic degenerative diseases and speed up the ageing process. This effect would add to the already heightened risk of atherosclerosis and diabetes in the overweight and obese. Vascular effects of low-carbohydrate diets It is not just risk factors for heart disease such as LDL cholesterol which are worsened on an HPLC diet, but also other measures of heart disease too. These include reduced myocardial perfusion and flow-mediated dilatation (increased arterial stiffness), and increased inflammation. Conversely a whole foods, low-fat, plant-based diet can prevent and reverse the progression of coronary heart disease (Ornish et al. 1998). The vascular effects can be seen acutely, even after only one meal: early research demonstrated that individuals following a low-fat vegetarian diet have greater blood vessel elasticity (Vogel et al. 1997). Flow-mediated vasoactivity decreased by 50% between 2 and 4 hours after a high-fat (50 g) 900 kcal non-vegetarian meal, whereas there was no decrease in vasoactivity after a low-fat vegetarian meal. There are several different human and animal studies of note, reporting impaired vascular health with HPLC diets. Starting with an important animal study, conducted at Harvard University, this illustrated the detrimental vascular effects of following an HPLC diet (Table 4.10) (Foo et al. 2009). Table 4.10. Macronutrient composition, and levels of cholesterol, inflammatory mediators and atheroma on a normal, Western and HPLC diet (mice study) Carbohydrate Fat Protein

Normal diet 65% 15% 20%

Western diet 43% 42% 15%

HPLC diet 12% 43% 45%

Cholesterol Inflam. Mediators

+++ +++

Atheroma 6 weeks Atheroma 12 weeks

0.45% 1.3%

2.2% 8.8%

5.4% 15.3%

Mice were fed either a normal mouse chow diet (65% carbohydrate, 15% fat, 20% protein), a typical Western diet (43% carbohydrate, 42% fat and 15% protein) or

an HPLC diet (12% carbohydrate, 43% fat and 45% protein). After 6 weeks autopsies revealed minimal atheroma in the normal mouse chow diet (0.4%), extensive atheroma in the western diet (2.2%) and more than double the Western diet's amount of atheroma in the HPLC diet (5.4%), despite the cholesterol and fat content of the latter two diets being the same (obtained from milk fat). The results after 12 weeks were also significant, with 1.3%, 8.8% and 15.3% atheroma respectively. The blood cholesterol levels were markedly increased in the Western diet and HPLC diet compared with the standard chow diet. As the levels of cholesterol and inflammatory mediators were the same in the Western diet and HPLC diet, the difference in atheroma in the two groups must be explained by non-lipid macronutrients i.e. the low level of carbohydrate and the high level of protein. Other results showed that the HPLC-fed mice had an impaired ability to generate new vessels in response to tissue ischaemia, along with reduced markers for vascular regenerative capacity. This study reveals that HPLC diets have adverse long term vascular effects, much worse than a typical Western diet, and they have a detrimental effect on neovascularisation in recovery after tissue ischaemia. More cause for concern! There are numerous human studies examining vascular health on HPLC diets. Short-term trials demonstrate an effect: one study compared a diet of at least 25g of saturated fat, with diets of 25 g of monosaturated fat, 25 g of polyunsaturated fat, and a highcarbohydrate low-fat diet. Protein content was kept constant at 16% (Keogh et al. 2005). The results found that after only 3 weeks, flow-mediated dilatation was substantially impaired, and there were increased blood inflammatory markers in the high-saturated fat diet compared with the low-saturated fat diets. The composition of the inferior outcome diet was 45% carbohydrate, 37% fat, 19% saturated fat, and for the superior outcome diet 65% carbohydrate, 18% fat, 7% saturated fat. Thus the lower the carbohydrate and the higher the saturated fat content (typical of an HPLC diet), the worse the arterial stiffness and atherogenic inflammatory markers. Another human study compared the effects of the Atkins diet (high-protein, lowcarbohydrate, high-fat) and the Ornish diet (normal-protein, high-carbohydrate, very lowfat) on lipids and endothelial function (Miller et al. 2009). The calorie intake was the same for both groups, and adjusted deliberately to ensure that the groups did not lose any weight (which would obscure the results). The Atkins diet contained 567 mg of cholesterol, 58% fat and 30% saturated fat. The Ornish diet contained only 114 mg of cholesterol, 9% fat and 3% saturated fat. Unfavourable biological effects were experienced on the Atkins diet: the LDL cholesterol was raised, atherothrombotic biomarkers increased, and there was reduced flow-mediated dilatation in the brachial artery (increased arterial stiffness). These effects, all risk factors for cardiovascular disease, occurred after only 4 weeks on the diet. In contrast, the Ornish diet resulted in significant reductions in LDL cholesterol by 16.6%, decreased atherothrombotic biomarkers, and improved flow-mediated dilatation. There was an inverse correlation between endothelial vasoreactivity and both fat and saturated fat intake. The higher the dietary saturated fat content, the more brachial artery flow-dilatation was impaired, and the higher the blood LDL cholesterol levels. The authors of the study warn that obese

individuals who already have an increased risk of coronary disease at baseline, have an accentuated risk with consumption of a diet which has unfavourable effects on both lipids and endothelial function. An 8 week study comparing isocaloric diets of 20% protein found that a low-fat diet (20% fat, 60% carbohydrate) significantly reduced overall systemic arterial stiffness, whereas a low-carbohydrate diet (20% carbohydrate, 60% fat) increased overall systemic arterial stiffness (Bradley et al 2009). Weight loss was the same in the two groups. Long term research on vascular health reports similar findings. For example, one study looked at the effects in cardiac patients of an HPLC (high fat) diet on coronary blood flow, compared with an adequate-protein low-fat high-carbohydrate diet (Fleming 2000). After one year, myocardial perfusion imaging (SPECT scanning) and echocardiography showed that the low-fat group had regression in both the extent and severity of coronary artery disease: there was recovery of viable myocardium in 44% of myocardial segments, with increased regional coronary artery blood flow, and reduced regional wall motion abnormalities. Furthermore, the low-fat group had improvements in several variables known to be important in the progression of cardiovascular disease: homocysteine, Creactive protein , lipoprotein a, triglycerides, total cholesterol, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, very low-density lipoprotein cholesterol, and fibrinogen levels. Conversely, the HPLC group had an overall cumulative progression of 40% in the extent and severity of coronary artery disease, and a worsening of their variables: for example fibrinogen increased by 14%, C-reactive protein increased by 61%, and lipoprotein a increased by 106%. The author concluded that â&#x20AC;&#x153;these results would suggest that high-protein diets may precipitate progression of coronary artery disease through increases in lipid deposition and inflammatory and coagulation pathways.â&#x20AC;? Another year long study comparing a very low carbohydrate, high saturated fat diet with an isocaloric high-carbohydrate, low-fat diet reported impaired flow-mediated dilatation in the low-carbohydrate group, with no difference in body weight (Wycherley et al. 2009). It was concluded that chronic consumption of low-carbohydrate diets may have detrimental effects on endothelial function. These studies add to the long list of known adverse effects of saturated fat and cholesterol on vascular function. They confirm the link between animal product consumption and impaired blood vessel dilation. One of the mechanisms for this could be that insulin decreases arterial tone: it forces arterial walls to relax, especially in microarterioles, and thus increases blood flow. Any diet causing a reduction in insulin levels or impaired insulin sensitivity (as in the case of high fat diets) would reduce blood flow by allowing arterial muscles to contract. Hypertension and diet The reason why the prevention of hypertension is so important is because for each 20mm Hg rise in systolic blood pressure and each 10 mm Hg rise in diastolic blood pressure,

there is more than twice the risk of death from cardiovascular disease (coronary heart disease and strokes) (Lewington et al. 2002). The effect is particularly strong for the risk of strokes. Components in HPLC diets such as red meat are a known risk factor: one epidemiological study on populations in the UK, USA, Japan and China, reported that a high red meat intake of 103 g/day was significantly associated with a rise in both systolic and diastolic blood pressure compared with lower intakes of red meat (Tzoulaki et al. 2008). To examine the effect of HPLC diets on blood pressure, it is useful to look at the numerous studies which have been conducted on vegetarian diets, as they contain a higher proportion of plant-based food than traditional HPLC diets, which contain large quantities of meat. Studies have consistently found vegetarians to have lower blood pressure, and to have a lower rate of hypertension than meat eaters, and that vegetarian diets are beneficial in the treatment of hypertension. (Appleby et al. 2002; Berkow & Barnard 2005; Leitzmann 2000; Myers et al. 2007; Fraser 1999; 2003; 2009). The new Adventist Health Study-2 cohort on 89,224 subjects found that on average the chances of developing hypertension are reduced by 55% in vegetarians and 75% in vegans (Fraser 2009). The amount of meat eaten has a direct correlation with blood pressure: semivegetarians, (consuming meat less than once a week), have a reduced risk of developing hypertension of 23%, while pescovegetarians (consuming no meat but some fish) have a reduced risk of 38%. Adopting a diet such as the Dietary Approaches to Stop Hypertension (DASH) diet, which is lower in meat and higher in fruit and vegetables (10 servings a day) and non-refined carbohydrates, significantly lowers blood pressure in both normal and hypertensive subjects (Sacks et al. 2001). Interestingly, the authors of the DASH diet initially wanted to devise a meat-free diet, but felt that the average American would be unable to stick to a strict vegetarian diet, and modified the original plan accordingly (Ornish 2008). What factors contribute to this blood pressure-lowering effect? One is the lower BMI seen in vegetarians, but there are also components of a plant-based diet which are known to help: beneficial effects of potassium, magnesium, antioxidants, a better unsaturated to saturated fat ratio, and fibre (Berkow & Barnard 2005). Another factor is soya protein, as it has been shown to reduce blood pressure (Jenkins et al. 2002; Rivas et al. 2002). Indeed, there is a particular advantage in substituting soya protein instead of animal protein in the diet because it also lowers LDL cholesterol as mentioned previously, and lowers homocysteine levels, thus reducing the cardiometabolic risk even more. This is thought to be due to the lower sulphur amino acid content in soya beans (Hermansen et al. 2001). It is imperative that a weight loss diet is designed to lower blood pressure, not increase it, so it is logical to reduce the amount of meat and increase the amount of fruit and vegetables: aims not compatible with current HPLC diets unless they are vegetarian.

One large meta-analysis of 9 cohort studies involving 257,551 subjects found that eating 6 or more portions of fruit and vegetables a day reduces the risk of strokes by 26% compared with eating 2 or less portions a day (He et al. 2006). Eating 3 to 5 portions resulted in a reduced risk of only 11%. As HPLC diets recommend on average only 5 portions of a restricted range of vegetables, cardiovascular disease risk reduction is not maximized. No diet should ban the consumption of fruit! Uric Acid Uric acid, the breakdown product of purines, found in high amounts in meat, fish and poultry, not only leads to an increased risk of gout and renal stones, but also contributes to cardiometabolic risk. This is because uric acid causes endothelial dysfunction by reducing the amount of endothelial nitric oxide, normally responsible for blood vessel dilatation (Gersch et al. 2008). The subsequent impaired dilatation, increased arterial stiffness and constricted vessels raise the blood pressure (increasing the risk of cardiovascular disease), and also impair oxygenation in the cardiac muscle, leading to cardiac ischaemia, angina and myocardial infarction. Reduced vasodilatation then causes insulin resistance, which further increases the risk of coronary heart disease. Traditional HPLC diets are rich in meat, fish and poultry, thus increasing plasma uric acid levels, with deleterious consequences. Other nutrients influencing cardiometabolic risk Antioxidants are an important factor in preventing cardiovascular disease, as they help destroy damaging free radicals which cause inflammation and vascular damage. The richest sources are fruit, vegetables and whole grains, foods which are limited or banned on HPLC diets. A large prospective study with a 12 year follow up on 31,035 Swedish women discovered that the highest quintile of intake of antioxidant-rich foods (fruit, vegetables, whole grains, tea and chocolate) had a 17% lower risk of stroke compared with women with the lowest quintile of intake (Rautiain et al. 2011). This effect was even stronger in a separate group of women with existing cardiovascular disease at baseline: there was a 45% reduced risk of haemorrhagic stroke in those with the highest quartile of intake compared with the lowest quartile. Usual confounding factors such as age, BMI, smoking, education and exercise were all controlled for. The contributions to the reduced risk were 50% from fruit and vegetables, 18% from whole grains, 16% from tea, and 5% from chocolate. The researchers stated that antioxidants, especially flavonoids may help improve endothelial function and reduce blood clotting, blood pressure and inflammation. Another point to consider for heart health is the importance of magnesium, as a diet lacking in this mineral increases the risk of heart disease. Magnesium rich foods include green leafy vegetables, nuts, soya, whole grains, bananas, apricots, prunes, apples and citrus fruit. Note that the latter six foods are all banned on HPLC diets. Heart disease risk is further increased by high levels of homocysteine, which can be lowered by folate and vitamin B6, (both rich in plant foods), and by vitamin B12, (obtainable from yeast extract, margarine, fortified cereals and soya milk and

supplements). Folate has also been found to help prevent breast cancer (Larsson et al. 2007). Folate levels are highest in vegans, intermediate in vegetarians and lowest in omnivores (Ambroszkiewicz et al. 2006), reflecting the higher intake of fruit, vegetables, whole grains, beans and seeds on a plant-based diet. In fact a plant-based diet actually exceeds the recommended daily allowance of folate. In my opinion any patient with a history of cardiovascular disease, including arrhythmias, should be excluded from an HPLC programme, as it is too high in saturated fat, leads to high uric acid levels which increase the risk cardiovascular disease, and is deficient in protective fruits and whole grains. Proof that low-carbohydrate diets based on animal protein lead to higher death rates from cardiovascular disease comes from a prospective cohort study conducted by Harvard University on 129,716 individuals. Low-carbohydrate dieters consuming animal sources of fat and protein had an increased cardiovascular mortality of 14%, with an overall increase in all-cause mortality of 23% (cancer deaths increased by 28%). This was compared with the low-carbohydrate dieters who consumed vegetable sources of fat and protein, who had a decrease in cardiovascular mortality of 23% and a decrease in all-cause mortality of 20% (Fung et al. 2010). In summary, some of the fundamental messages from the cardiometabolic risk research bodies are that dysplipidaemia causes atheroma and insulin resistance (leading to further atheroma), and that raised uric acid levels cause hypertension and insulin resistance, leading to atheroma and impaired coronary blood flow. Added to these factors is the increased risk of impaired blood flow with high saturated fat diets, and the promotion of atherosclerosis with high AGE foods. Should the medical profession be promoting a diet which leads to increased levels of cholesterol, uric acid and AGEs? The aim should be to lose weight using foods which reduce cardiovascular disease risk factors, not increase them.

5. CANCER I have attended several medical conferences organised by the World Cancer Research Fund and the Association for the Study of Obesity on the topics of obesity, diet and cancer. Some of the conclusions are presented here. In the UK, 27% of all deaths are due to cancer (30% for men and 25% for women). The most common cancers in men are, in order with the commonest first, cancers of the prostate, lung, colon and bladder. For women, the commonest cancers are of the breast, lung, colon and the endometrium. In terms of cancer deaths for men, the commonest are due to lung, prostate, colorectal and oesophageal cancer. For women the commonest deaths are from lung, breast, colorectal and ovarian cancer (Cancer Research UK 2009). Estimates on the proportion of cancers due to diet are from 32% (Willett 1995) to 35% (Doll & Peto 1981), with the Western cancers of breast, colorectal and prostate cancer being up to 80% attributable to diet (Willett 1995). On studying the relationship of HPLC diets to cancer, one needs to examine the evidence that meat consumption is associated with a higher risk of cancer, as meat occurs in abundance in traditional HPLC diets. A prospective study on 121,342 individuals found that cancer mortality was increased by 10% with ingestion of red meat, and 16% with ingestion of processed meat (Pan et al. 2012). Conversely, results from the EPICOxford study report that vegetarians have a reduced risk of developing cancer: by 12% for all cancers, and as much as 64% for stomach cancer, 53% for bladder cancer, 45% for lymphomas and haemapoietic cancers, and 31% for ovarian cancer (Key et al. 2009). Furthermore, The World Cancer Research Fund states that two foods absent from HPLC diets are protective: whole grains and pulses can reduce our cancer risk. Proof that traditional HPLC diets can promote cancer comes from the Harvard prospective cohort study on 129,716 individuals, comparing animal-based lowcarbohydrate diets with vegetable-based low-carbohydrate diets: the animal-based dieters had an increase in cancer mortality of 28% (Fung et al. 2010). Before looking at the epidemiological evidence about diet and cancer, I will first examine the effect of protein on tumour development, as that is of great relevance when discussing the health implications of HPLC diets. Cancer-promoting agents There are many different compounds found in food which are associated with the development of cancer. These include animal protein, insulin like growth factor-1 (IGF1), carcinogens such as heterocyclic amines, polycyclic aromatic hydrocarbons, n-nitroso compounds, haem iron, saturated fat and arachidonic acid. Effect of protein on tumour development What do we know about cancer and protein intake from animal experimental studies? The National Institute for Health and three different American cancer research

foundations have been funding research looking at the effect of protein on tumour development for the last 20 years (Campbell 2006). More than 100 scientific papers have been published on this topic, as documented in Chapter 3 of The China Study by Professor Colin Campbell. I shall outline the key findings of the studies. For example aflatoxin was fed to rats to predispose them to get liver cancer. Their diets were then modified to contain 20% protein or 5% protein. Only the rats fed 20% protein developed liver cancer and the 5% protein rats got none. Other studies illustrated how protein consumption actually caused tumour initiation: it changed how aflatoxin is detoxified by the enzymes in the liver. Increased protein intake increased the level of enzyme activity that converts the aflatoxin into the dangerous aflatoxin metabolite, which then binds to and mutates the DNA. Conversely, on a lowprotein diet tumours were reduced: less aflatoxin entered the cell, cells multiplied more slowly, the harmful enzyme complex was reduced in activity and quantity, and fewer aflatoxin-DNA adducts were formed. Further studies showed how protein is involved in tumour promotion. Tiny clusters of cancer cells which appear just after initiation is complete are called foci. By watching foci develop, it was observed that foci development was almost entirely dependent on how much protein was consumed, regardless of the amount of aflatoxin exposure. Interestingly, animals fed on 20% protein that were switched to 5% protein after 6 weeks, had their foci sharply decrease. When their protein intake was increased to 20% again, their foci development was turned on once again. By varying the amount of protein, it was found that foci did not develop until 10% of dietary protein was reached. This has relevance to humans because the protein requirement for growth and health in rats and humans is remarkably similar. The recommended daily allowance for protein is 10% of calories from protein (50-60 g a day), yet the average western diet contains 15-16% protein (70-100 g a day). Does this place us at risk for getting cancer? These animal studies hint that it does. Did it make any difference what type of protein was used in these experiments? For all these experiments, casein was used, which makes up 87% of cowâ&#x20AC;&#x2122;s milk protein. When the experiments were repeated using plant protein, there was no promotion of cancer growth, even at higher levels of intake. 20% soya protein diets did not form early foci; neither did 20% gluten (wheat protein) diets. All the animals fed 20% casein diets were dead at 100 weeks, unlike the 5% protein diet animals which were all alive and healthy at 100 weeks. These experiments were then repeated using mice primed with the hepatitis B virus to see the effect of protein on liver tumour development. The findings were all replicated. The 22% casein diet turned on the expression of the viral gene to cause cancer, whereas the 6% casein diet showed almost no such activity. Professor Campbell also reports other research groups' findings on increasing intakes of casein with non-liver cancers: casein promoted the development of breast cancer in rats which had been primed with two experimental carcinogens. This operated through a

network of reactions to increase cancer and through the same female hormone system that operates in humans. He documents other different types of nutrients which have been examined for their role in cancer promotion/reversal, including dietary fats and caretenoids. The results of these studies showed that nutrition was far more important in controlling cancer promotion than the dose of the initiating carcinogen. Furthermore, the emerging pattern was that animal-based nutrients increase tumour development, whilst plant-based nutrients decrease tumour development (Campbell 2006). The effects of animal protein on colonic cancer have also been documented. For example, rats were fed diets including 15% casein, 25% casein or 25% cooked beef in order to examine the effects on the colon (Toden et al. 2006). The results showed that the high casein diet caused twice as much colonic DNA damage compared with the low casein diet, and that the red meat diet caused caused 26% more colonic DNA damage. Furthermore, the thickness of the colonic mucus layer was reduced by 41% in the casein and red meat groups. Interestingly the detrimental changes were abolished with the inclusion of 48% high amylase maize starch, high in resistant starch. (The resistant starch causes an increase in caecal short chain fatty acids which have important anti-cancer properties.) As HPLC diets are traditionally high in both red meat and casein, and provide minimal resistant starch (present in abundance in unripe bananas and cold cooked potatoes), one can conclude that they increase the risk of colon cancer. There are several proposed mechanisms for high dietary protein being associated with carcinogenesis in the colon. If excess protein enters the colon, it is fermented by gut microflora into protein fermentation products such as ammonia and phenols (Macfarlane & Cummings 1991). These are toxic to the mucosa and show cancer promoting properties (Corpet et al. 1995): they have been shown to disturb cellular metabolism and DNA synthesis, decrease cell life span and increase cell turnover. Furthermore the amino acid methionine (abundant in meat products) can directly promote carcinogenesis (Duranton 1999). Carcinogens found in dairy foods: insulin-like growth factor 1 (IGF-1) So we have published data in animal experimentation which shows that animal protein promotes growth of tumours, and high casein diets allow more carcinogens into cells. What do we know about other potential cancer-promoting agents in animal foods from research studies? Milk is a good example because it contains many different hormones and growth factors designed to ensure the growth and well-being of a young calf. What happens if the chemicals designed to stimulate cell growth in a newly-born animal are exposed to adult human tissue? Will the same growth signals cause inappropriate cell proliferation and differentiation in both normal and cancerous cells? Research studies have reported that consuming animal protein increases the levels of the hormone insulinlike growth factor 1 (IGF-1), which is a risk factor for cancer because it can make cells grow out of control. IGF-1 is well-established as a potent mitogen (a substance that induces cell division) to many different cell types, and also inhibits apoptosis (cell death)

in cancer cells. Indeed, the IGF-1 receptor is over-expressed in many different tumour cell lines, and numerous trials have been conducted investigating the IGF-1 receptor as a target for chemotherapy (Scartozzi et al. 2011). Several international studies link high plasma levels of IGF-1 to a greatly increased risk of leukaemia, and cancers of the colon, breast, prostate, lung, bladder and pancreas (Hursting et al. 2004). For example, women with the highest levels of IGF-1 have 7 times the risk of developing premenopausal breast cancer as those with the lowest levels (Hankinson et al. 1998). The risk is also significantly increased for postmenopausal breast cancer (De Lellis 2003). In fact, the chair of the Cancer Prevention Coalition wrote a petition to the FDA and US Department of Health and Human Services, detailing 22 publications reporting increased levels of IGF-1 with the increased risk of breast cancer, 16 publications on the increased risk of colon cancer, and 10 publications on the increased risk of prostate cancer (Epstein 2007). He also mentions three in vitro studies consistently showing that IGF-1 enhances the growth of cancer cell lines of the breast, colon, prostate, breast, bladder, lung, stomach, oesophagus, liver, pancreas, kidney, thyroid gland, brain, ovary and endometrium. IGF-1 is found in cowâ&#x20AC;&#x2122;s milk, surviving the pasteurisation and digestive process: pasteurisation actually increases the amount by 70% (Juskevich & Guyer 1990), and IGF-1 is a peptide, not a protein, and so is readily absorbed by the blood stream (Epstein 2007). Additionally, casein, the main protein in milk, protects IGF-1 from degradation (Xian 1995). Furthermore, short-term feeding of IGF-1 to rats results in significant growth promotion (Juskevich & Guyer 1990; Epstein 1996). Many studies have demonstrated a link between higher IGF-1 levels and milk consumption (Morimoto et al. 2005). In a study of over 200 people, 3 servings of non-fat milk a day over a period of 12 weeks increased blood IGF-1 levels by 10% (Heaney et al. 1999). Supporting this data, research found that men drinking at least one pint a day of milk had 16% higher levels of IGF-1 than men drinking less than half a pint a day (Gunnell et al. 2003). Likewise, research in women reported a gradual increase in IGF-1 as dietary milk intake increased (11% higher from the lowest quintile to the highest quintile). This positive association was also true for dietary protein: as protein intake increased, so did IGF-1 levels (Holmes et al. 2002). This is particularly relevant in the examination of the medical consequences of HPLC diets. In another study, increasing cowâ&#x20AC;&#x2122;s milk intake from 200ml a day to 600ml a day produced a 30% increase in IGF-1 in young boys (Hoppe et al. 2004b). Some meats fare no better: official figures show that dairy cow meat contains even more IGF-1 than milk (Plant 2007). Over the past few decades IGF-1 levels in milk have increased dramatically due to selective stock breeding of high-yielding dairy cows, which have higher levels of naturally occurring bovine growth hormone. This hormone is responsible for increasing the levels of IGF-1 in the milk. In the USA the situation is even worse due to the use of recombinant bovine growth hormone, rBGH, (banned in Europe, Canada, Japan, New

Zealand and Australia) which results in even higher levels of IGF-1. The Epstein petition documents 12 different studies which report excess levels of IGF-1 in rBGH milk, by between 4- and 20-fold (Epstein 2007). Included in these studies were admissions by the manufacturers of rBGH and the Food and Drug Administration (FDA), that levels of IGF-1 were consistently increased. Thus the rise in breast cancer rates can partly be explained by the steady rise in dairy IGF-1. Hyperinsulinaemia Humans produce high levels of their own IGF-1 in response to the state of hyperinsulinaemia, secondary to metabolic syndrome. As both IGF-1 and hyperinsulinaemia are both mitogenic, through stimulating cell proliferation and decreasing apoptosis of cancer cells, it is also desirable to lose weight and restrict calories to reduce these biomarkers. Incidentally the diabetic drug metformin reduces breast cancer risk by 23% (Bosco et al. 2011). This drug acts by improving insulin sensitivity, reducing activation of the IGF-1 receptor, and inhibiting tumourigenesis pathways (e.g. mTOR) (Memmot et al. 2010; Tosca et al. 2010). The fact that it acts as an anti-cancer drug via inhibiting the action of IGF-1, further underlines the importance of minimising IGF-1 in the diet, and hence minimising dairy foods. Carcinogens found in meat, fish and poultry Traditional HPLC diets are high in animal products such as meat, fish and poultry. Cooking these foods at high temperatures results in the formation of several different carcinogenic chemicals which have been linked in both animal experimentation studies and epidemiological studies to multiple different cancer sites (National Cancer Institute 2010). Details of the individual chemicals involved are documented in the 11th Report on Carcinogens by the National Toxicology Programme, listing the evidence for the increased risk of cancer in humans (US Department of Health and Human Services 2005). There are four different types of carcinogenic agents found in cooked meat, fish and poultry: heterocyclic amines (HCAs), polycyclic aromatic hydrocarbons (PAHs), Nnitroso compounds (NOCs), and haem iron (Santarelli et al. 2008; Key et al. 2004; Cross & Sinha 2004; WCRF 2011). The World Cancer Research Fund’s report on colorectal cancer, which was updated in 2011 states: “There are several potential underlying mechanisms for a positive association of red meat consumption with colorectal cancer. Red meat contains haem, which promotes the formation of potentially carcinogenic N-nitroso compounds as well as cytotoxic alkenals forms from fat peroxidation. Red meat cooked at high temperatures, results in the production of heterocyclic amines and polycyclic aromatic hydrocarbons that can cause colon cancer in people with a genetic predisposition.” (WCRF 2011).

Heterocyclic amines Heterocyclic amines (HCAs) are formed during the cooking of muscle-derived foods such as meat, poultry and fish, by condensation of creatinine with amino acids. (Creatinine is a breakdown product of creatine, a key constituent of muscle). Higher temperatures and longer cooking time times increase the amount of HCAs produced: frying, grilling, barbecuing and broiling produce more than stewing or steaming (Layton et al. 1995). There are several different types which are listed as human carcinogens, the most abundant HCA in foods being 2-amino-1-methyl-6-phenylimidazo(4,5-b)pyridine PhIP. The highest concentrations of PhIP are found in grilled chicken, followed by welldone steak and hamburgers, and barbecued fish. Other types of carcinogenic HCAs are found in grilled fish, well-done bacon, grilled, fried or barbecued chicken, beef steak and beef hamburger, minced beef, pork chops, fried eggs and pan scrapings used for gravy. It is also one of the carcinogens in cigarette smoke (US Department of Health and Human Services 2005). Cooked chicken is particularly high in HCAs because it contains large amounts of the amino acids phenylalanine, tyrosine and isoleucine, which contribute to HCA formation. In contrast grilled veggie burgers and other grilled vegetarian foods such as mushrooms contain no HCAs or negligible levels (Nagao & Sugimura 2000). Even at low concentrations, HCAs have been shown to have a high degree of potency, and induce DNA damage and initiate cancer (Felton et al. 2002). Studies have consistently shown that mutations are caused in test systems such as rodents, primates and cultured rodent and human cells. The 11th Report on Carcinogens lists the numerous different cancer sites which are caused by HCAs: cancers of the oral cavity, lung, stomach, liver, small intestine, colon, breast, skin, and prostate, and lymphoma and leukaemia. In monkeys, HCAs induce tumours of the breast, colon and prostate (Sugimura et al. 2004). In human studies, DNA adducts of HCAs have been detected in tissues, and are associated with increased risks of breast, colon and prostate cancer (Wilson et al. 2007). Interestingly, these are all the commonest cancers in the West. Well-done meat is associated in population studies with increased risks of colorectal, breast, prostate, oesophageal, gastric, pancreatic and lung cancer (Zheng & Lee 2009). Red meat intake is also associated with a higher risk of cancers of the kidney (comparing intake over 62 g a day with intake of less than 9 g a day) (Daniel et al. 2012). Specifically, this study reported that the risk of renal cell carcinoma was increased by 20 to 30%, and the risk of papillary renal cell carcinoma was increased 2-fold with intake of HCAs (Daniel et al. 2012). Research now suggests that humans are even more susceptible to the carcinogenic effects of PhIP, the most abundant HCA, than animal test models. One study cross-bred mice who were genetically susceptible to tumours, so that they expressed human sulphotransferases (hSULT), known to activate PhIP (Svendsen et al. 2011). When administered PhIP, the incidence of colon tumours in mice was 31% in the mice without

the hSULT, and 80% in those with hSULT. The average number of colon tumours was 0.4 in the non hSULT mice and 1.3 in the hSULT mice. Thus traditional experimental carcinogenic models of PhIP in rodents substantially underestimate the cancer risk to humans, as rodents do not normally possess the PhIP activating gene. The levels of carcinogens in grilled chicken are so high, that a lawsuit was filed by the Physicians Committee for Responsible Medicine (PCRM), against high street restaurant chains including McDonalds, Burger King and TGI Fridays. Over 100 grilled chicken items were found to contain PhIP (PCRM 2008). Burger King settled the lawsuit by agreeing to post warning signs in its California restaurants that its grilled chicken contained PhIP Polycyclic aromatic hydrocarbons Polycyclic Aromatic Hydrocarbons (PAHs) are carcinogenic chemicals formed when muscle meat including beef, pork, fish, and poultry is fried, grilled, barbecued, charcoal broiled, cured or smoked (Cross & Sinha 2004; Jagerstad & Skog 2005). They form due to the incomplete combustion of an organic compound, and are also present in cigarette smoke. The 11th Report on Carcinogens details PAHs causing cancer of the stomach, lung, liver and breast, and states that they are human carcinogens (US Department of Health and Human Services 2005). Epidemiological evidence suggests that they play a significant role in human cancers (Norat & Riboli 2001). Indeed, high consumption of well-done, fried, or barbecued meats is associated with increased risks of colorectal (Cross 2010), pancreatic (Stolzenberg-Solomon et al. 2007) and prostate cancer (Sinha et al. 2009). In addition, the risk of renal cell carcinoma is increased by 20 to 30%, and the risk of papillary renal cell carcinoma is increased 2-fold with intake of PAHs (Daniel et al. 2012). Details of ongoing studies can be found on the National Cancer Instituteâ&#x20AC;&#x2122;s website (National Cancer Institute 2010). N-nitroso compounds N-nitroso compounds (NOCs) are carcinogenic chemicals formed from the nitrosation of amines using nitrites and nitrates. Exogenous sources are smoked, cured, salted and processed meat products. Curing is the process of adding salt and nitrites or nitrates to food, in order to inhibit bacterial growth, and results in the highest levels. NOCs are found in ham, bacon, hotdogs, smoked fish, cheese and beer (Lijinsky 1999). They are also one of the carcinogens in cigarette smoke. Endogenous NOCs are formed in the human gut from red meat ingestion. This is the result of fermentation of amino acids by certain types of gut bacteria. Haem iron from meat dramatically increases NOC formation (Cross et al. 2003). Animal studies have demonstrated that meat-fed rodents have significantly increased NOCs in their faeces, depending on the type of meat: grilled bacon-fed rats have 10-20 times more (Parnaud et al. 2000); hotdog-fed mice have 4-5 times more, and beef-fed mice have 2-3 times more NOCs than non-meat fed rodents (Mirvish et al. 2003). The 11th Report on Carcinogens lists the multiple different cancers caused in rodents and dogs 99

through ingestion of NOCs: cancers of the tongue, pharynx, trachea, lung, oesophagus, stomach, intestine, colon, kidney, bladder, breast and leukaemia (US Department of Health and Human Services 2005). Human studies also demonstrate the link between meat ingestion and NOC formation: fresh red meat produces 3 times more NOCs in the faeces in high compared with low intakes (Bingham et al. 1996). Endogenous formation has an important role, as it has been shown that NOC concentrations triple during transit from mouth to faeces (Hughes et al. 2001). Red meat ingestion results in DNA damage in exfoliated bowel cells. One study published in Cancer Research, showed that on examination of exfoliated bowel cells from individuals fed either meat or vegetarian diets, the red meat eaters had on average 4 times the rate of DNA mutation, (increasing the likelihood of cancer), compared with the vegetarians (Lewin et al. 2006). The DNA mutation occurred after only 10 days on the red meat diet (420g of red meat a day). A third control group of a high red meat combined with a high-fibre diet did not protect the cells from DNA mutation, with similar results to the red meat group. Consistent with these findings were that the amounts of n-nitroso compounds in the faeces were on average 3 and a half times higher in the red meat dieters compared with the vegetarian dieters (the range was between 2and 20-fold). Haem iron Prospective cohort studies have demonstrated that haem iron more than doubles the risk of colorectal cancer (2.18 times) (Lee et al. 2004). Haem iron in red meat can promote carcinogenesis through four different mechanisms (Santarelli et al. 2008). The first mechanism is that haem is metabolised in the gut into a cytotoxic and promoting factor: it increases cell proliferation in the mucosa (Sesink et al. 1999). The second mechanism is that haem induces peroxydation of fat in foods and in the gut, thus forming toxic lipoperoxides with promote colorectal cancer (Sawa et al. 1998). This process is potentiated by the nitrites of cured meat, as nitrite binds to the haem iron to yield even more lipoperoxides. The third mechanism is that haem catalyses endogenous N-nitrosation, which facilitates the formation of carcinogenic NOCs, and the activation of carcinogenic HCAs (Lakshmi et al. 2005; Cross et al. 2003). Haem catalyses this reaction even in the absence of gut flora, so adds a significant contribution to the endogenous NOC formation from red meat. For example, haem from fresh red meat was found to increase endogenous NOC concentrations 4-fold, and processed meat 6.5-fold (Lunn 2007). Thus nitrosation increases the toxicity of haem in cured products. The International Agency for Research on Cancer (IARC) confirms that haem is a major determinant of NOC formation (IARC 2010).

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The fourth mechanism is that iron increases the formation of mutagenic free radicals (Lund 1999). In vitro, haemoglobin is toxic and genotoxic in colonic cell lines and in cultures of human colonocytes: there is uptake of iron by the cells, followed by free radical oxidative stress (Glei et al. 2006). The presence of these four different categories of carcinogenic compounds found in meat, poultry and fish is an important reason for elimination of these foods from the diet, and as traditional HPLC diets contain an excess of these foods, they should be avoided. If plantbased proteins are used instead, (which actually contain cancer fighting phytochemicals), cancer risk is reduced substantially. Saturated fat and arachidonic acid A high saturated fat diet is known to increase cancer risk. There are several studies which illustrate the tumour promoting effects of a high saturated fat diet in breast cancer (Khalid et al. 2009), non-Hodgkins lympoma (Zhang et al. 1999), and in colorectal carcinoma (van Suan et al. 2009). The former rodent study reported a tumour promoting effect of a low-carbohydrate (35%), high-fat (45%) diet (mostly in the form of lard) compared with a high-carbohydrate (70%), low-fat (10%) fat diet. (The protein content was the same at 20%). Note that in comparison, classic HPLC diets have even higher levels of fat and saturated fat: the Atkins diet is 60% fat and 26% saturated fat, and Protein Power is 53% fat and 19% saturated fat (Eades 2009). The implications for cancer promotion are alarming. The Zhang et al. study demonstrated that the risk of non-Hodgkins lymphoma was more than twice as likely in people who ate beef, pork or lamb at least once a day compared with less than once a week. The result of the consumption of trans fats was similar, more than doubling the risk of non-Hodgkins lymphoma between the highest and lowest quintiles. The van Suan et al. study examined the effects of feeding a reduced carbohydrate (42.7%), high-fat (42%) diet to mice. The fat was mostly saturated, deriving all from milk fat. The livers of these mice were compared with mice fed standard chow i.e. a normal carbohydrate (58%) and low-fat (13.5%) diet. The high-fat diet group rapidly developed hepatic steatosis and livers treble the weight of the low-fat diet mice. Histology after 14 months on the diet revealed primary dysplastic nodules in 100% of the mice, compared with 0% of the mice on the standard low-fat diet. Furthermore, when colonic cancer cells were injected into the spleen, the number of metastatic tumours in the liver in the high-fat diet group was 4.8 times the number found in the low-fat diet group. Thus a high saturated fat diet caused a microenvironment in the liver conducive to the development of both primary and secondary tumours. There are several different potential mechanisms for the link between dietary fat and carcinogenesis. Arachidonic acid is the precursor to several different pro-inflammatory eicosanoids, which directly activate nuclear factor kappa beta (NF-kappa B). This gene transcription factor drives the inflammatory responses of the immune system even more,

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and is strongly linked with a raised cancer risk. Saturated fats indirectly activate NFkappa beta, and contribute to cancer risk in this way. Confirming these mechanisms, the WCRF/AICR updated report on colorectal cancer states: “Saturated fatty acids can induce expression of inflammatory mediators and stimulate increased insulin production” (WCRF 2011). Both these states increase the risk of cancer. Another mechanism for animal fats leading to an increased risk of cancer, is through the microflora system. The WCRF/AICR updated report on colorectal cancer states: “Diets high in fat lead to increased levels of bile acids in the colon. Bile acids are metabolised by the bacterial flora to deoxycholic acid, which can promote cancer in rodents. The conversion of bile acids to secondary bile acids such as deoxycholic acid is decreased by the lower pH induced by short-chain fatty acids produced in diets high in non-starch polysaccharides. Also, deoxycholic acid is less soluble at a lower pH, which may limit its adverse effects.” (WCRF 2011). Thus one of the mechanisms for fibre lowering the risk for colorectal cancer is explained, as carbohydrate-feeding microflora fermentation products such as butyrate are acidic: there is then less conversion of bile acids to carcinogenic secondary bile acids. Global research studies and world health advisory body recommendations What do we know from global research studies and cancer? Sir Richard Doll and Sir Richard Peto, the Oxford based world-leading epidemiologists, have stated that in the West, 35% of cases of cancer are due to diet (Doll & Peto 1981). This figure has been revised over subsequent years, with estimates for the archetypal Western cancers of 50% for breast, 70% for colorectal and 75% for prostate cancers (Willet 1995). The latter review acknowledged that for the three Western cancers, the estimate could be as high as 80% of these cancers being avoidable by the modification of diet. The highlighted nutritional factors are the detrimental effects on cancer of animal protein and animal fat, and the beneficial effects of whole grains, fruit and vegetables. This cancer-promoting dietary effect can also be summarised as the Westernisation of the diet: increased consumption of meat and dairy products, resulting in high intakes of protein and fat, and a reduced intake of unrefined starchy foods. This is of relevance when examining the effects of traditional HPLC diets, as they have much in common with Western diets: they are high in animal protein and fat, and low in the cancer protective foods such as whole grains, root vegetables and fruit. At an Obesity and Cancer conference that I attended, graphs were displayed showing how rates of colon and breast cancer in Japan have increased steadily since the 1950's, correlating with both an increase in the consumption of milk, meat and animal fat, and a decrease in complex carbohydrates: the Westernisation of the diet (ASO 2008). Table 5.1 is taken from Nutrition Trends in Japan (Matsumura 2001). It summarises the trends in Japanese nutritional intake (calorie intake remained constant).

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Table 5.1. Japanese nutritional intake in g per capita per day Fat g Animal fat g Carbohydrate g Protein g Animal protein g

1950 18 418 68 17

1965 36 14.3 384 71.3 28.5

1996 58.9 29.3 274 80.1 43.1

Rice g All grains incl. wheat g Meat g Eggs g Dairy g

338.7 476.8 8.4 5.6 6.8

349.8 418.5 29.5 35.2 57.4

166.5 262.9 77.8 42.1 133.9

Here we seen that meat consumption has risen nearly 10-fold, egg consumption nearly 9fold, and dairy consumption nearly 20-fold, all at the expense of carbohydrate (rice and grain) consumption (calorie intake has stayed the same). Contrast these figures with Japanese morbidity statistics, in the 2007 National Health and Nutrition Survey, which reveal all-time-high levels of diet-related diseases (National Institute of Health and Nutrition 2007): 1. Of people over the age of 40, 50% of men and 20% of women are strongly suspected of having metabolic syndrome. 2. Of people over the age of 40, 19.4% of men and 10.2% of women have been diagnosed with diabetes. 3. 30.4% of men and 20.2% of women are obese. Now contrast these nutritional intake figures with the statistics on cancer: from 1983 to 2002, bowel cancer has increased by 92% in men, and 47% in women (Center et al. 2009), and the statistics on breast cancer reveal that from 1959 to 1997, the age-adjusted incidence of breast cancer per 100,000 women rose from 27.5 to 74, i.e. nearly trebling (Minami et al. 2004). The Westernisation of the Japanese diet is resulting in the Westernisation of Japanese diseases. More evidence for this is demonstrated in studies which report that when Japanese people migrate to Hawaii, and adopt the Western diet there, rates of colon and breast cancer increase dramatically (Pike et al. 2002). What do the world's health advisory bodies say? In 2007, The World Cancer Research Fund (WCRF) and the American Institute for Cancer Research (AICR) published their second expert report Food, Nutrition, Physical Activity, and the Prevention of Cancer: a Global Perspective. This report was based on a series of rigorous systematic literature reviews and evaluations of 7,000 studies on diet, physical activity and obesity in relation to cancer risk. An expert panel of world-renowned scientists assessed decades of research

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results, and issued recommendations for cancer prevention. It has become the most authoritative statement on the evidence linking diet to the development of cancer. In May 2011, the WCRF and AICR issued an update to the 2007 report, having looked at an additional 263 papers on colorectal cancer. The updated conclusions have been incorporated into the summary provided here. The report states that colorectal cancer had a convincing increased risk with consumption of red and processed meat: consuming an extra 120 g a day of red and processed meat increases the risk of colorectal cancer by 28%, in a dose response relationship (WCRF 2011). There was also a suggestive increased risk with cancers of the oesophagus, stomach, pancreas, lung, endometrium and prostate. Foods containing iron had a suggestive increased risk with colorectal cancer. Diets high in calcium had a probable increased risk for prostate cancer, and cheese and saturated fat had a suggestive increased risk for colorectal cancer. Total fat had a suggestive increased risk for postmenopausal breast cancer. Smoked foods and grilled or barbecued animal foods had a suggestive increased risk for stomach cancer. The conclusions on foods which promoted cancers were: "People who eat various forms of vegetarian diets are at low risk of some diseases including some cancers... Recommendation is to limit intake of red meat to no more than 300g (cooked) a week, and avoid processed meat... Red or processed meats are convincing causes for some cancers." Now looking at foods which prevent cancer, the WCRF and AICR report stated that foods which contained dietary fibre had a convincing decreased risk of colorectal cancer, with a suggestive decreased risk for oesophageal cancer. Vegetables had a probable decreased risk of cancers of the mouth, pharynx and larynx, oesophagus, stomach, pancreas, colorectum, prostate and lung. There was a suggestive decreased risk for vegetables with ovarian and endometrial cancer. Pulses had a suggestive decreased risk for stomach and prostate cancer. Fruits had a probable decreased risk of cancers of the mouth, pharynx and larynx, oesophagus, stomach and lung, with a suggestive decreased risk for cancers of the nasopharynx, pancreas, liver and colorectal cancer. With relevance to HPLC diets, which ban fruit, the updated report states: â&#x20AC;&#x153;Fruits are sources of vitamin C and other antioxidants, such as carotenoids, phenols, and flavonoids, as well as other potentially bioactive phytochemicals. Antioxidants trap free radicals and reactive oxygen molecules, protecting against oxidation damage. In addition, flavonoids found in fruit directly inhibit the expression of a cytochrome P450 enzyme, which helps to metabolise toxins and has been associated with increased risk of lung cancer, primarily in smokersâ&#x20AC;? (WCRF 2011). This statement underlines just how unhealthy HPLC diets are, due in part to their lack of fruit, which is such an important source of anti-cancer phytochemicals. The WCRF report continues, "Non-starchy vegetables, and fruits, probably protect against some cancers. Being typically low in energy density, they probably also protect against weight gain. This is best made up from a range of various amounts of nonstarchy vegetables and fruits of different colours including red, orange, yellow, green,

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white and purple, including tomato-based products and allium vegetables such as garlic. Non-starchy roots include carrots, swede and turnips... Recommendation is to eat mostly foods of plant origin. Population average consumption of non-starchy vegetables and of fruits to be at least 600 g daily. Relatively unprocessed grains and or pulses, and other foods that are a natural source of dietary fibre, to contribute to a population average of at least 25 g non-starch polysaccharide daily. Eat relatively unprocessed grains and/or pulses with every meal - these foods are low in energy density and so promote healthy weight. People who consume starchy roots (potato, sweet potato, yam) as staples also to ensure sufficient non-starchy vegetables, fruits and pulses." The conclusion was "The goals and recommendations here are broadly similar to those that have been issued by other international and national authoritative organisations. They derive from the evidence on cancer and are supported by evidence on other diseases. They emphasize the importance of relatively unprocessed grains, non-starchy vegetables and fruits, and pulses, all of which contain substantial amounts of dietary fibre and a variety of micronutrients, and are low or relatively low in energy density. These, and not foods of animal origin, are the recommended centre of everyday meals." (WCRF/AICR 2007). The WCRF/AICR update in 2011, based on new evidence, confirms this recommendation, stating that the goal is to consume a plant-based diet based on food containing fibre, such as whole grains, fruit, vegetables and pulses such as beans (WCRF 2011). Note that non-starchy roots include carrots, swede and turnips, so it is wrong for any HPLC diet to classify these as "starchy vegetables" and thus ban their intake. Carrots in particular have a suggestive decreased risk for developing cervical cancer, and are extremely high in the essential antioxidant beta carotene, which has a probable decreased risk for oesophageal cancer. Other important antioxidants, found abundantly in plant foods but not in meat, include flavonoids, vitamin C (a probable decreased risk for oesophageal cancer), vitamin E (a probable decreased risk for oesophageal and prostate cancer), folate (protective against pancreatic cancer), carotenoids (protective against oral and lung cancer), and lycopene and selenium (protective against prostate cancer). The updated WCRF report on colorectal cancer lists the many different plant food constituents which could contribute to a protective effect of non-starchy vegetables. â&#x20AC;&#x153;These include dietary fibre, carotenoids, folate, selenium, glucosinolates, dithiolthiones, indoles, coumarins, ascorbate (vitamin C), chlorophyll, flavonoids, allylsulphides, flavonoids, and phytoestrogens. Antioxidants, one of the multiple potential mechanisms, trap free radicals and reactive oxygen molecules, protecting against oxidation damage.â&#x20AC;? (WCRF 2011). For example folate has particular anti-cancer actions: â&#x20AC;&#x153;Folate plays an important role in the synthesis, repair, and methylation of DNA. Abnormal DNA methylation has been

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linked to aberrant gene expression and also to cancers at several sites. Folate may also reduce HPV proliferation in cells.â&#x20AC;? (WCRF 2011). The latter effect would protect against cervical cancer. Apart from green leafy vegetables such as lettuce, spinach and asparagus, the highest concentrations of folate are found in fortified breakfast cereals, which are banned on HPLC diets: this would eliminate a rich source of this essential nutrient. (Other good plant-based sources include lentils, peas and beans, also banned on HPLC diets). In fact antioxidants have been acknowledged by international health advisory bodies to help protect against over 60 different diseases, including the major killers of heart disease and cancer. I have attended several medical conferences on the topics of obesity, nutrition and cancer, and all the above findings are confirmed repeatedly, with the message of the necessity of eating 7 portions of fruit and vegetables a day for women and 9 a day for teenage boys and men, in order to prevent cancer: ideally 5 portions of vegetables, with 4 portions of fruit; each portion is 80-100g of food (World Health Organisation/National Cancer Institute 2003). The minimum is 600 g a day of fruit and vegetables a day, equivalent to 7 Â˝ portions a day (WCRF/AICR 2007). Cancer Research UK has published a quantitative analysis in The British Journal of Cancer of the number of cancers attributable to dietary factors, based on UK statistics. It has examined dietary surveys from 2000 and matched them to cancer incidence in 2010. It is clear that the UK population is not consuming nearly enough fruit and vegetables. The minimum aim is for 400 g a day, but the mean consumption over all adult age groups is only 230 g a day. The range is as low as 132 g in the 19 to 24 age group, rising to only 290 g in the 50 to 64 age group. Using equations based on large scale epidemiological meta-analyses of cancer, the results of the analysis are printed in Table 5.2 (Parkin & Boyd 2011). Table 5.2. Percentage of cancers attributable to a deficit in fruit and vegetable consumption % of cancers attributable to a deficit in fruit and vegetable consumption Oral cavity & pharynx Oesophagus Larynx Stomach Lung

56% 46% 45% 36% 9% (fruit only)

The overall number of cancers in 2010 which were attributable to inadequate fruit and vegetable consumption was 14,902. Compare this to 1,857, the number of fatalities on the road in the UK in 2010. This is something which the whole population needs to address urgently. HPLC diets, which all limit vegetables to only certain types and ban fruit, are making the problem of inadequate fruit and vegetable consumption even worse.

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I now quote for the World Cancer Research Fund UK website (WCRF 2012): â&#x20AC;&#x153;Plant foods and cancer prevention WCRF UK recommends eating more of a variety of vegetables, fruits, whole grains, and pulses such as beans. Basing our diets on plant foods (like vegetables, fruits, whole grains and pulses such as beans), which contain fibre and other nutrients, can reduce our risk of cancer. For good health, WCRF UK recommends basing all meals on plant foods. When preparing a meal, aim to fill at least two thirds of your plate with plant foods like vegetables, rice, pasta, lentils and cereals. Aim to eat these types of foods with every meal and opt for whole grain options whenever possible.â&#x20AC;? These recommendations bear no resemblance to HPLC diets, which risk producing the opposite effect and enhancing cancer risk. Cancer-fighting phytochemicals The top cancer-fighting foods and their phytochemicals are listed in Table 5.3 (Plant 2007). Table 5.3 The top cancer-fighting foods and their phytochemicals Greens Cabbage - indoles to stimulate enzymes that detoxify carcinogens; Broccoli - sulphorophane to stimulate enzymes that detoxify carcinogens; -isothiacyanates to inhibit enzymes that activate carcinogens and stimulate enzymes that detoxify carcinogens Kale, romaine lettuce, spinach - lutein and zeaxanthin - antioxidants Garlic, onions (especially effective against colorectal cancer) - allicin, diallyl sulfide, s-allyl-L-cysteine - to inhibit enzymes that activate carcinogens; stimulate enzymes that detoxify carcinogens. -allyl sulphides inhibit colon tumour formation and inhibit cell growth Flax seeds (ground and oil) - lignans - to block oestrogen and progesterone receptors on cancer cells The above foods are usually allowed on HPLC diets. However there are many more top cancer fighting foods which are not included or greatly limited: fruit for example, which, on its own, protects against many different cancers. The following lists healthy phytochemical-containing foods which are discouraged on an HPLC plan.

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Berries e.g. raspberries, blackberries, strawberries, grapes -ellagic acid â&#x20AC;&#x201C; antioxidant - phyto-oestrogens Grapes - phenols to inhibit formation of carcinogens such as nitrosamines; stimulate detoxification of carcinogens Citrus fruit - the flavonoids diosmin and hesperedin - decrease biochemicals which influence cell growth and proliferation Red fruit e.g. tomatoes, watermelon - lycopene - antioxidant Apples - non-citrus flavonoids genistein and daidzein - phyto-oestrogens and antioxidant Whole grains e.g. oats, wheat, rye, quinoa - phytate to inhibit cell proliferation and metastasis - lignans to prevent oestrogen and prostaglandin hormones from binding to their receptors (retarding cell proliferation) - phytochemicals which induce the production of the detoxifying enzyme GST - phytochemicals which suppress cholesterol synthesis (cancer cells synthesise and accumulate cholesterol faster than normal cells) Yams and sweet potatoes - phyto-oestrogens Beans, peas and lentils (especially effective against stomach and prostate cancer) â&#x20AC;&#x201C; phyto-oestrogens - blocking oestrogen and androgen receptors on cancer cells - antioxidants - protease inhibitors - inhibit the transformation of normal cells into cancerous ones; inhibit the expression of genes and cellular processes that promote cancer Soya and soya products e.g. tofu and miso (not the highly refined ones) - phyto-oestrogens - antioxidants In my opinion, any patient with cancer should be excluded from an HPLC programme, not only because of the high amount of animal protein and fat, but also because most of this list of the top cancer fighting foods is excluded or greatly limited. Examining these cancer protective foods in more detail, pulses (legumes) are high in both fibre and phytochemicals, which have the potential to prevent and interrupt the cancer process in many ways. These include antioxidant and anti-inflammatory activity, which

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can protect the cells from free radicals and other damaging products. The Adventist Health Study reported that consuming legumes 3 or more times a week caused a reduction in colon cancer by 47%, compared with consuming legumes less than once a week (Singh & Fraser 1998). However, this beneficial effect was not seen in white meat (poultry and fish) eaters. (I have already discussed how white meat has a strong association with colon cancer due to the formation of heterocyclic amines and poly aromatic hydrocarbons). More data from the Adventist Health Study reports that legumes also reduce the risk of pancreatic cancer (Fraser 1999). The WCRF/AICR contributes to this list, as stated earlier, by reporting that pulses protect against stomach and prostate cancer. The Adventist study also found that fruit reduced the risk of lung, prostate and pancreatic cancer. We can remind ourselves that the WCRF/AICR quote a long list of cancers that fruit protects against: a probable decreased risk of cancers of the mouth, pharynx and larynx, oesophagus, stomach and lung, with a suggestive decreased risk for cancers of the nasopharynx, pancreas, liver and colorectal cancer. For example in the EPIC study, fruit consumption (particularly apples and pears) reduced the risk of lung cancer by 8% for each 100 g of intake (Leinseisen et al. 2007). In a Czech study, a high intake of fruit was associated with a 31% reduction in the risk of lung cancer in men (Kubik et al 2008). Apples were particularly effective in protecting against both squamous and small cell cancers. An important criticism of HPLC diets is that they do not contain whole grains, pulses or fruit, and hence could be vastly improved by their inclusion for important cancerprotecting reasons. I would like to examine a few individual cancers, looking at research into links with diet and possible mechanisms for the associations. Bowel Cancer Colorectal (bowel) cancer is the third most common cancer in the world, with incidence rates being approximately 10-fold higher in developed countries than in developing countries (Key et al. 2004). In men's cancer mortality statistics, it comes third in terms of cancer deaths. There is a strong association between meat consumption and colorectal cancer mortality (Pin et al. 2011). In fact the World Cancer Research Fund and American Institute for Cancer Research recommend consuming less than 300 g (cooked) of red meat a week to avoid the risk of bowel cancer, and no processed meat at all - bacon, hot dogs, salami, ham, corned beef - as it is such a strong risk for bowel cancer (WCRF/AICR 2007). I have already elaborated on the four different types of cancer-causing agents in meat. The WCRF has publicised some of these mechanisms in a fact sheet: they report that haem from red meat and nitrates from processed meat, both cause the production of n-nitroso compounds, which are known to damage DNA in the cells (WCRF 2008).

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Interestingly, one US study looked at carcinogens produced when cooking food until it was well done: the beef burgers produced 44 times more carcinogens than the soya burgers, and the bacon produced 346 times more. Furthermore, damaging free radicals were much higher in the cooked bacon and beef burger, whilst the soya burger produced none (Woodvine 2006). In addition, haem-iron found in meat, but not plants, can also increase free radical production and damage the bowel wall cells. (This increase in oxidative damage has also been linked to liver cancer and other diseases). For example, one population-based case control study found that the risk of colon cancer was 1.7 times greater if 34 g of red meat was consumed a day, and 2.5 times greater if 52 g was consumed, compared with less than 12 g a day (Butler et al. 2003). The Adventist Health Study, which looked at 34,192 individuals, found that non-vegetarians had an increased risk of colon cancer of 88% compared with vegetarians (Fraser 1999). Incidentally, this study also found a strong association with eating beef and bladder cancer. The Adventist Health Study also compared the effect of eating red with white meat (poultry and fish) on the risk of colon cancer, in 32,051 individuals (Singh & Fraser 1998). Red meat eaters (who ate white meat less than once a week) had an increased risk of colon cancer of 90% if eating red meat at least once a week, whilst the white meat eaters (who ate red meat less than once a week) had over triple the risk (3.29 times), if eating white meat between one and four times a week. Eating both red and white meat more than four times a week resulted in a tripling of the risk of colon cancer. Thus poultry, as well as red meat, is linked to bowel cancer incidence. There have been several meta-analyses of prospective and case control studies on the link between eating red meat and the risk of developing colorectal cancer. Table 5.4 summarises the findings of three large meta-analysis studies, on the excess risk of colorectal cancer compared with a minimal intake of less than 20 g a week. Table 5.4 The excess risk of colorectal cancer with meat intake Fresh red meat per 100 g/day Larsson 2006 +0.18 Norat 2002 +0.20 Sandhu 2001 +0.17

Processed meat per 100 g/day

Relative risk per g of processed meat/red meat

+0.30 +1.20 +1.96

1.64 6.0 11.53

Consuming more than 100 g of meat a day, increases the risk of colorectal cancer even more, in a dose-response relationship. (The Larsson and Norat studies examined the effect of consuming 120 g red meat a day, resulting in an increased risk of 22% and 24% respectively.) What is particularly remarkable, are the small amounts of processed meats necessary to produce a substantial increase in risk. For example in the Sandhu study, a

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mere 20 g a day of processed meat was enough to increase the risk of colorectal cancer by 49%. A meta-analysis of 10 prospective studies since the WCRF/AICR report on the meatcolorectal cancer connection, found that colorectal cancer risk increases approximately linearly with increasing intake of red and processed meats, up to approximately 140 g/day, where the curve approaches its plateau. The relative risk was 1.22 for the highest versus lowest intake of red and processed meat, with a 1.17 times increased risk for red meat for every 100 g/day increase, and 1.18 times increased risk for processed meat for every 50 g/day increase (Chan et al. 2011). Cancer Research UK included meat consumption in its analysis of cancers attributable to dietary factors, mentioned earlier. It used large scale meta-analyses to generate an increased relative risk for colorectal cancer of 1.21 for consumption of every 50 g of processed meat a day, and 1.29 for every 100 g of red meat a day. This was combined with data from nutritional surveys in 2000, and UK cases of cancer in 2010. The results were that in the UK in 2010, 21% of colorectal cancers were attributable to meat consumption, or 8,411 cases a year (Parkin 2011). Intakes of red meat were on average 73 g a day for men, and processed meat 45 g a day, with the younger age groups consuming 63 g a day of each. Based on the above results, the average UK meat eating man is substantially increasing his risks of colorectal cancer by around 20% compared with a non-meat eater. (Women had on average a lower intake of 47 g and 23 g for red and processed meat respectively, but still had an increased risk of colorectal cancer). Cancer Research UK states in the introduction of the study: “There are no dietary guidelines concerning recommended levels of consumption of red and processed meat; as for alcohol, it is assumed that ‘less is better’ and that there is no threshold below which consumption presents no risk. In this section, we assume that the optimum (or target) is zero consumption.” Thus compared with the World Cancer Research Fund, Cancer Research UK is even more strict on meat consumption, recommending no red or processed meat at all. It should be noted that HPLC diets typically contain both bacon and ham, neither of which should be consumed at all according to the WCRF and AICR. Furthermore the HPLC message on meat is to “eat freely”, completely disregarding recommendations by the WCRF and Cancer Research UK. As bowel cancer is the third most common cancer in the UK (and it is increasing), and it is also one of the most preventable, the WCRF recommends limiting consumption of red meat, and basing meals on plant foods such as whole grains and vegetables. The advice is to consume at least 600 g of fruit and vegetables a day (which equates to 7 ½ portions). HPLC diets contain much more than 300g of red meat a week, and usually only 400 g of vegetables a day, (equating to 5 portions), with no fruit.

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Fibreâ&#x20AC;&#x2122;s protective effect for bowel cancer The protective effect of a whole grain, plant-based diet with plenty of fruit, vegetables and fibre is well-documented. The WCRF now states that fibre has a convincing protective effect against colorectal cancer (WCRF 2011). One large study (EPIC) based in 10 European countries, confirmed that the more fibre is eaten, the lower the risk of colon cancer: the risk of left sided colon cancer was reduced by 55% in people consuming at least 25 g a day of fibre, compared with those eating 15 g or less (Bingham et al. 2005). This was after full adjustment for factors including folate. Starchy vegetables and complex carbohydrate foods confer a protective effect. Another piece of research based on 7 UK cohort studies, using accurate food diaries and controlling for folate, alcohol and energy intake, found that there was 34% less risk of colorectal cancer in the highest quintile of fibre intake, compared with the lowest (Dahm et al. 2010). Examining the source of fibre, the updated WCRF report on colorectal cancer says that eating 3 servings a day of whole grains reduces the risk of colorectal cancer by 21% (WCRF 2011). A serving could be 30 g of uncooked whole grain rice, quinoa, barley, oats or pasta (half a cup cooked), or one slice of wholemeal bread, or 30 g (one regular sized bowl) of high fibre cereal. Note that milk, cheese and meat contain no fibre at all, and HPLC diets specifically ban whole grains (the Atkins diet has less than 10 g fibre a day), so this is another reason why a traditional HPLC diet could be construed as a cancer-promoting diet. A large systematic review and meta-analysis of nearly 2 million participants from 25 prospective cohort and case control studies backs up the evidence that whole grains and cereal fibre reduce the risk of colorectal cancer (Aune et al. 2011). It concluded that there was an inverse association between total dietary fibre, cereal fibre and whole grains and the risk of colorectal cancer, and the risk is reduced in a dose response fashion. Cancer Research UK has conducted an analysis of cancers attributable to lack of dietary fibre, using the same system as their analyses for fruit and vegetable and meat consumption, as mentioned earlier. The relative risk values for colorectal cancer were 0.84 per 10 g of fibre a day i.e. a 16% reduced risk for every 10 g of dietary fibre, or a reduction in risk of 2.9% for every 1 g increase in fibre. They used UK recommendations of 23 g of fibre a day (equivalent to 18 g of non-starch polysaccharide) as a target. Analysis revealed that 12.2% of cases of colorectal cancer were due to lack of fibre, equivalent to 4,856 cases a year. UK fibre consumption is not adequate: an average of only 16.1 g a day for all age groups, with the main sources being 43% from bread, rice, pasta and cereal; 16% from potatoes, and 4% from baked beans. Only 20% came from vegetables. Note that HPLC diets ban all of these items apart from vegetables, so 63% of the usual source of fibre is eliminated. As national fibre intake is not enough, a healthy diet should encourage the consumption of more fibre, not less!

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What is the potential mechanism for a fibrous complex carbohydrate diet protecting against cancer? Increasing the amount of fibre speeds up intestinal transit time, thereby reducing the amount of time the gut is exposed to cancer-forming substances and diluting faecal carcinogens. Furthermore, when fibre reaches the large bowel it is fermented by beneficial bacteria, producing substances such as short chain fatty acids (e.g. butyrate) which have health benefits and can slow the spread of cancer cells: firstly, short chain fatty acids induce apoptosis of cancerous cells, cell cycle arrest, and differentiation in experimental studies (differentiated tumour cells resemble normal cells, and tend to grow and spread at a slower rate than undifferentiated tumour cells, which lack the structure and function of normal cells and grow uncontrollably). Secondly, as explained before, an acidic environment reduces the conversion of bile acids to secondary bile acids, which are known to promote cancer. The latter effect is enhanced by the fact that secondary bile acids are less soluble in an acidic environment, which diminishes their toxic effects (WCRF 2011). Whole grain fibre has additional anti-cancer effects through the high concentrations of antioxidants, minerals, vitamins, phytate, lignans, phenolic acids and phytoestrogens. Folate and magnesium, present in large amounts in whole grains are also associated with a reduced risk of colorectal cancer. Finally, as higher intakes of dietary fibre and whole grains protect against weight gain and type 2 diabetes, cancer risk is further reduced due to the association between increased cancer risk and raised cancer risk and insulin resistance (Aune et al. 2011). The interaction between colon cancer, diet and colonic bacterial flora, is illustrated by examining the diets and microflora of populations with different colon cancer risks. There is a dramatically higher incidence of colorectal cancer in African Americans (60 cases per 100,000) compared with Native Africans (less than one case per 100,000). One study compared samples between these two populations, and found that in the African Americans, (i.e. consumption of a Westernised diet) there were higher mucosal proliferation rates (by 7-fold), higher colonic populations of toxic hydrogen and secondary bile-salt-producing bacteria, and lower concentrations of lactobacilli, than in the Native Africans (O'Keefe et al. 2007). Dietary analysis revealed that in comparison with the with the Native Africans, African Americans consumed more protein (94 g vs. 58 g/day), animal protein (51 g vs. 26 g/day) fat (114 g vs. 38 g/day), saturated fat (35 g vs. 9 g/day), cholesterol (300 mg vs. 165 mg/day), and meat (in a 3 day analysis, all the African Americans had eaten red meat, whereas only 12% of the Native Africans had eaten red meat). The authors discussed the role of sulphur-reducing bacteria such as Desulfovibrio vulgaris, which feeds on sulphur rich amino acids found in animal protein. The resulting hydrogen sulphide is cytotoxic, causing impairment of cytochrome oxidase, tissue metabolism, mucus formation and DNA methylation. The implications are that an HPLC diet, which, like the Western diet, is high in protein, animal protein, fat, saturated fat and cholesterol, will increase the risk of bowel cancer via an unfavourable alteration in bowel microflora.

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The Rowlett Research Institute in Aberdeen published research on obese subjects following either a normal, moderate or low carbohydrate diet (Duncan et al. 2007). After 4 weeks, the amount of beneficial butyrate-producing bacteria in the gut was reduced as the carbohydrate level decreased, and subsequently the amount of faecal butyrate, which helps prevent bowel cancer, was also reduced. Carbohydrate intakes of 400 g, 164 g and 24 g corresponded with faecal butyrate levels of 18 mM, 9 mM and 4 mM respectively. This was followed up by a rat study, which demonstrated that protein-induced damage to DNA in colon cells is prevented by butyrate (Bajka et al. 2008). Another 4 week study compared stool samples of high, moderate and low-carbohydrate diets, and discovered that the HPLC diet decreased the proportion of butyrate in faecal short-chain fatty acid concentrations (Russel et al 2011). Furthermore, in the HPLC and moderate-carbohydrate diets, there were greatly reduced concentrations of faecal antioxidant phenolic acids such as ferulate (derived from fibre), which like butyrate, have cancer protective properties. Adding to the cancer risk was the increased concentration of faecal N-nitroso compounds in the HPLC and moderate-carbohydrate diets. These changes were concomitant with a reduction in the Roseburia/Eubacterium rectale group of microflora bacteria (beneficial gram positive anaerobes). The composition of the diets of the high-carbohydrate diet was 85 g protein, 116 g fat, and 360 g carbohydrate; the high-protein and moderate-carbohydrate diet was 139 g protein, 82 g fat, and 181 g of carbohydrate, and the HPLC diet was 137 g protein, 143 g fat and 22 g of carbohydrate. Thus again we see HPLC diets causing reduced faecal cancer-protective compounds and beneficial bacteria, and increased faecal carcinogenic compounds, even when the carbohydrate is as high as 181 g a day. A high-carbohydrate, normal-protein diet has the opposite effect. A longer term 8 week study comparing isocaloric diets of HPLC content with moderate carbohydrate content, similarly reported unfavourable markers of bowel health with the HPLC diet compared with the moderate-carbohydrate diet: lower stool mass, infrequent bowel movements, a reduction in faecal short chain fatty acids such as butyrate, and a marked reduction in numbers of the beneficial bacteria bifidobacteria (Brinkworth et al. 2009). The HPLC regime consisted of meat, poultry, fish, eggs, full fat milk, cheese, nuts, and up to 2 to 5 cups of green vegetables a day, with no bread, cereal, pasta, lentils, potatoes or fruit, unlike the moderate carbohydrate diet. There was a much lower amount of fibre (20 g of carbohydrate; 13 g of fibre) than universally recommended, compared with the moderate-carbohydrate diet (171 g carbohydrate; 32 g fibre.) Thus consuming such a diet is proven to have adverse effects on bowel health. All of these intervention studies indicate that following an HPLC diet increases the risks of bowel cancer, via a reduction in cancer protective metabolites such as butyrate, and an increase in detrimental metabolites. Conversely a high-carbohydrate and high-fibre diet produces beneficial microflora which generate cancer protective metabolites. Other proposed mechanisms linking fibre to protection against bowel cancer are that some strains of the probiotic Lactobaccilus (which feeds on fibrous prebiotic foods) have the ability to bind to cancerous heterocyclic amines (Wollowski et al. 2001), and also

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they decrease the enzyme activity of beta glucoronidase, which is known to generate carcinogens in the gut (Brady et al. 2000). Breast cancer The China Study reports that in China, where traditionally very little dairy is consumed, the age-adjusted incidence of breast cancer ranges from 0 in 100,000 women in rural China (where minimal dairy is consumed) up to 20 in 100,000 women in urban areas (where a more Westernised diet has been adopted) (Campbell 2006). Compare this to UK figures reporting an incidence of 124 per 100,000 women, with a lifetime risk of developing breast cancer of one in eight women (Cancer Research UK 2008). Migration studies of rural Chinese, Japanese and Filipino populations (all with cancer rates 4 to 7 times lower than the West) moving to the West show an 80% increased risk of breast cancer within 10 years, and rates similar to the Western population within two generations (Deapen et al. 2002; Pike et al. 2002). Clearly there is something about the Western lifestyle which dramatically increases cancer risk. The Shanghai Breast Cancer Study, which looked at 1,446 cases of breast cancer in China, found that women who ate a Western-style diet based on meat, chicken and desserts have almost double the risk of postmenopausal oestrogen receptor positive breast cancer than those on a traditional plant-based diet of beans, soya and vegetables. (Cui et al. 2007). There was a 30% increased risk for all types of postmenopausal breast cancer. Harvard Medical School backed up this finding with two studies confirming that red meat and high-fat dairy foods such as whole milk, butter, cream cheese, and cheese were associated with breast cancer (Cho et al. 2003; Cho et al. 2006). They reported that individuals eating 4 servings of red meat a week had a 14% increased risk of hormone dependent breast cancer, rising to double the risk if eating 1 Â˝ servings of red meat a day (equivalent to eating a burger and a sausage). One study on over 13,070 women by the Dunn Human Nutrition Unit in Cambridge found that women who ate 34 g of saturated fat a day were twice as likely to develop breast cancer as those who ate the least (highest quintile of intake compared with the lowest quintile of intake). There was a 22% increase in risk for each rise in quintile of saturated fat intake. (Bingham et al. 2003). The European Prospective Investigation into Cancer and Nutrition (EPIC) obtained results from a huge sample of 328,238 women. It found a similar increased risk of breast cancer of 21% in postmenopausal women with the highest quintile of saturated fat intake compared with the lowest quintile of intake (Sieri et al. 2008). These results are supported by previous pooled analyses of cohort studies reporting a 9% increase in risk with each 5% increase in saturated fat (Smith-Warner et al. 2001). A Swedish prospective cohort study on 49,261 women reported a 45% increase in the incidence of postmenopausal breast cancer with each 10 g increase in dietary saturated fat (Lof et al 2007). Other research has used the fatty acid composition of red blood cells as a marker for dietary fat intake. A Chinese study documented a high saturated fat (palmitic acid)

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concentration in red blood cells being associated with more than double the risk of breast cancer: there was an odds ratio 2.18 for the highest quartile concentration compared with the lowest quartile concentration (Shannon et al. 2007). Palmitic acid is found in butter, pork, beef, lamb, eggs, palm oil and chocolate. Note that all but the latter food is found in abundance on HPLC diets. Interestingly there is a correlation between dairy consumption and many different hormone dependent cancers including breast, prostate and ovarian cancer. What are the mechanisms for the link between animal product consumption and hormone dependent cancers? I have already outlined how a high animal protein diet causes favourable conditions for cancer cells to initiate and proliferate, and how there are high levels of IGF-1 (a well-known mutagenic agent) in dairy products and some meat. Another mechanism is that as protein intake increases, so do the circulating levels of IGF-1 (Yu & Rohan 2002). In fact reducing dietary protein intake by 30% decreases levels of IGF-1 significantly. This is of relevance when examining the effects of HPLC diets, which would be expected to increase IGF-1, due to the high animal protein content. Another cancer-promoting agent in animal products is oestradiol (Outwater et al. 1997). Of the three different types of oestrogens, oestradiol is the most stimulating to the breast. 75% of commercial milk is from pregnant cows, which produce high levels of oestrogens, including oestradiol (Qin et al. 2004). In fact, 60-80% of the oestrogen in the Western diet comes from cowâ&#x20AC;&#x2122;s milk and dairy products, the remaining 20-40% being derived from other animal products such as meat (Plant 2007). Free oestrogens are found in greater quantities in whole milk compared with skimmed milk, which would partly explain why increased dietary fat (over 25%) has been shown to increase plasma oestradiol levels (Wu et al. 1999). Indeed, decreasing dietary fat to 10-25% of total calorie intake reduces serum oestradiol by between 2.7% and 10.3% (Wu et al. 1999). The link between saturated fat and breast cancer has been mentioned earlier. Prospective cohort studies have shown that raised oestradiol levels are associated with subsequent development of postmenopausal breast cancer (Hankinson et al. 1998; Thomas et al. 1997). The latter study reported that oestradiol levels were 29% higher in those women who later developed breast cancer. It is thought that oestradiol may exert a direct effect on mammary tissue and also stimulate the expression of IGF-1. For example, the practice of giving oestradiol implants to beef cattle in America is widespread, and results in over 50% higher levels of IGF-1 in the meat than untreated meat (Simpson et al. 1997). Dairy products also contain prolactin, which has been shown to promote the growth of breast and prostate cancer cells in laboratory cultures (Haraguchi et al. 1992; Clevenger et al. 1995). Other constituents include epithelial growth factor (EGF) and insulin-like growth factor II (IGF-II), all of which are mitogenic in breast and prostate cells, and are absorbed by the blood through the gut wall (Yu & Rohan 2002). In fact cowâ&#x20AC;&#x2122;s milk has been shown to contain over 35 different hormones and 11 growth factors! (Grosvenor et al. 1992). Interestingly, all these different growth factors and hormones are present even

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in organic milk. The conclusion is that a diet high in saturated fat and dairy products such as HPLC diets may place patients at a higher risk of hormone dependent cancers and other types of cancer. Ovarian cancer Ovarian cancer is the fourth most common cause of cancer deaths among women in the UK (Cancer Research UK 2008). Lactose is a risk factor, as one study in over 80,000 American women showed that women who consumed the most lactose had twice the risk of ovarian cancer than those who drank the least (Fairfield 2004). A Swedish prospective cohort study showed that women who consumed 4 or more servings of dairy foods a day had double the risk of ovarian cancer compared with low or non-dairy consumers (Larsson et al. 2004). A pooled analysis of 12 cohort studies concluded that there was an increased risk of ovarian cancer of 19% if consuming more than 30 g/day of lactose (i.e. 750 g milk) compared with less than 10 g/day (i.e. 250g milk) (Genkinger et al. 2006). The highest rates of ovarian cancer are in Iceland with 16.2 women affected per 100,000, followed by Sweden with 15.2, and 13.7 in the UK. The lowest rates are 1.6 per 100,000 for Korea, followed by 2.1 for Mali and 4 in China. Food consumption data shows a strong positive correlation with milk, followed by animal fats and cheese. Conversely pulses actually protect against ovarian cancer (Gamma & Sotto 2005). The Adventist Health Study found a positive correlation between consuming both meat and cheese with ovarian cancer: the relative risk was 2.42 times higher in individuals eating meat at least once a week, compared with vegetarians, and 2.02 times higher in those eating cheese at least 3 times a week compared with those eating cheese less than once a week (Kiani et al. 2006). Conversely consuming tomatoes at least 5 times a week reduced the risk of ovarian cancer by 68%, and a higher fruit consumption also reduced the risk. The EPIC Oxford trial has reported a reduced risk of ovarian cancer in vegetarians of 31% (Key et al. 2009). Thus in order to protect against ovarian cancer, a traditional HPLC diet containing meat and dairy foods is not advised. Prostate cancer One in 16 men in the UK will develop prostate cancer. It is the commonest cancer in men (a quarter of all male cancer diagnoses), and it is the second commonest cause of cancer deaths in men. The age standardised incidence is 98 per 100,000 men in the UK (Cancer Research UK 2008). By comparison, in rural China the incidence is only 1 in 100,000 (IARC 2002). There are clear links with diet, with many different studies reporting an elevated risk with a high intake of meat and dairy products compared with a low intake: processed meats, red meats and dairy (2-fold elevation in risk) (Michaud et al. 2001); processed meat (2.7-fold elevation in risk) (Rodriguez 2006); and well done meat (2-fold elevation in risk for advanced prostate cancer) (Koutros et al. 2008). These findings are consistent with research indicating that vegetarians are half as likely to get prostate

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cancer as meat eaters (Fraser 1999): this Adventist Health Study found that eating meat at least once a week resulted in a 54% higher risk of developing prostate cancer than a vegetarian diet. There also appears to be a link between eating eggs and prostate cancer. Men who consumed 2.5 or more eggs per week had an 81% increased risk of lethal prostate cancer compared with men who consumed less than 0.5 eggs per week (Richman et al. 2011). This research was based on data collected from 27,607 men for 14 years. The association between a high intake of dairy foods and prostate cancer is interesting. Results from 142,251 men in the European Prospective Investigation into Cancer and Nutrition (EPIC) were that for every 35 g/day increase in consumption of dairy protein, the risk of prostate cancer rose by 32% (Allen et al. 2008). The authors site one possible mechanism being due to dairy causing an increase in circulating insulin-like growth factor 1 (IGF-1) levels, which has been supported by other researchers (Crowe et al. 2009): there is a strong positive correlation between blood IGF-1 levels and prostate cancer. For example one large Swedish prospective study reported that of men aged under the age of 59, those with the top quartile IGF-1 levels have 4.12 times the risk of developing prostate cancer (Stattin et al. 2004) compared with those in the bottom quartile. Furthermore, vegans have been shown to have lower levels of IGF-1 of between 9% (Allen et al. 2000) and 13% (Allen 2002), compared with non-vegans. In terms of the link between prostate cancer and disease progression, diet is also strongly implicated. A review of 25 observational and clinical studies showed that prostate cancer patients who ate the least meat and dairy products lived longer: short term dietary modifications to reduce saturated fat were associated with indices of reduced disease progression. In contrast, men who ate the most saturated fat were 3 times more likely to die from prostate cancer than those who ate the least (less than 10% of total calories as saturated fat) (Berkow et al. 2007). The detrimental effect of dairy milk consumption on prostate cancer appears to exert its effects from a young age: a long-term study reported that daily milk consumption in adolescence was associated with a 3.2-fold increased risk of advanced prostate cancer in later life, compared with consumption of milk less than daily (Torfadottir et al. 2012). Eating more beans, lentils, pulses, peas, tomatoes, raisins, dates and other dried fruit significantly reduces the risk of prostate cancer (Mills 1989). For example researchers at the Preventative Medicine Research Institute in California used a vegan diet to lower PSA levels and slow the growth of early prostate cancer. The participants, who ate vegetables, fruit, whole grains and pulses including soya products, had PSA levels 10% lower than those on a typical Western diet, and also had levels of cancer inhibitors in the blood that were eight times higher (Ornish et al. 2005). Note that all these food groups are banned on HPLC diets, apart from certain vegetables. In fact, the message â&#x20AC;&#x153;fruit is to be avoidedâ&#x20AC;? is dangerous when considering the evidence that eating fruit offers some protection against prostate cancer: there is an inverse correlation between fructose intake and prostate cancer (Giovannucci et al. 1998).

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Lung cancer A population-based case-control study found a strong association between red meat intake and the risk of lung cancer (Alavanja et al. 2001): the risk between the highest quintile of intake compared with the lowest quintile of intake was more than trebled (odds ratio of 3.3), even after controlling for fat, saturated fat, cholesterol, fruit, yellowgreen vegetable consumption and smoking history. Meat, a food found in abundance on HPLC diets, is associated with an increased risk of lung cancer, whilst carrots, a food banned on HPLC diets, is associated with a decreased risk of lung cancer: eating carrots at least 5 times a week protects against the development of lung cancer (Rachtan 2002). The protective effect of soya was examined in two different meta-analyses of epidemiological studies, in which soya foods were also found to reduce the risk of prostate cancer (Yan & Spitznagel 2009; Hwang et al. 2009). It is thought that this is partly due to the protective effect of isoflavones such as genistein and daidzein.

S o u r c e

Looking at the non-Western cancers, results from the EPIC-Oxford study report that vegetarians have a reduced risk of developing cancer: by 12% for all cancers, and as much as 64% for stomach cancer, 53% for bladder cancer, 45% for lymphomas and haemapoietic cancers, and 31% for ovarian cancer (Key et al. 2009). The World Cancer Research Fund states that whole grains and pulses can reduce our cancer risk. Final proof that traditional HPLC diets can promote cancer comes from the Harvard prospective cohort study on 129,716 individuals, comparing animal-based lowcarbohydrate diets with vegetable-based low-carbohydrate diets: the animal-based dieters had an increase in cancer mortality of 28% (Fung et al. 2010).

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6. RENAL FUNCTION Chronic kidney disease is an increasingly common and serious condition, leading, if untreated, to end stage renal disease requiring dialysis or a renal transplant. It is also a major predictor of cardiovascular disease. The main risk factors for chronic kidney disease (CKD) are diabetes, hypertension and obesity. The prevalence of CKD in the general population is 16.8% for adults aged 20 or more, rising to 39.4% in individuals over the age of 60. The prevalence of CKD in obesity is 19.8%, in hypertension it is 24.6% and in diabetes it is 40.2% (Centres for Disease Control and Prevention 2007). As the average BMI at which diabetes is diagnosed is 30, a substantial proportion of obese patients are at risk for CKD. Furthermore, hypertension is common, affecting 31.5% of men and 29% of women in the UK (NHS Information Centre 2010), and 29% of US adults (Cutler et al. 2008). As the early stages of CKD are asymptomatic, it is often under diagnosed and under treated. This is of great relevance when examining HPLC diets, as the mainstay of treatment of CKD is a restricted protein diet: no more than 0.6 to 0.8 g/kg body weight (Franz & Wheeler 2003). Any animal protein above the body's requirements overloads the renal metabolism, reducing the filtering abilities, accelerating any decline in renal function and increasing the risk of renal stones. Measurements of the glomerular filtration rate (GFR) are a good indication of kidney function, as long term, GFR decreases as kidney function declines. Chronically, ingestion of a high-protein diet, in older people or those with mild renal insufficiency, is associated with a much greater renal decline than ingestion of a lower protein diet: one study over 11 years found that the highest quintile of protein intake (92.3 g a day) caused a 3.51 times higher risk of 15% or more decline in GFR than the lowest quintile intake (61 g a day; Knight et al. 2003). This study reported that the link with accelerated renal decline was true only for non-dairy animal protein, not vegetable protein. Another study of a 5075 year old population found that a daily dietary increment of 0.1g of protein per kg was associated with an increased risk for microalbuminuria, which is a major predictor of renal and cardiovascular disease (Hoogeveen et al. 1998). In patients with mild renal insufficiency, there is an increased relative risk of total mortality with an additional 15 g of protein per day (Dwyer et al. 1994). Acutely, ingestion of protein in healthy individuals increases the postprandial GFR (Brandle et al. 1996), thus straining the kidneys. However, this link between protein and renal decline only applies to animal protein, as soya protein does not increase the GFR or renal blood flow (Messina & Messina 2010). The Knight et al. study illustrates how animal proteins play a role in the progression of renal disease, unlike vegetable proteins: the reduction in kidney function only occurred with the intake of non-dairy animal protein, not vegetable protein. Thus anyone with obesity, who is at a much higher risk of diabetes and therefore mild renal insufficiency, would be ill-advised to follow a high animal protein diet due to this risk of decline in renal function.

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The damaging impact of high-protein diets on the kidneys has influenced medical bodies' committees' advisory statements on dietary guidelines: to reduce chronic disease risk. Acceptable Macronutrient Distribution Ranges (AMDR) have been set by the Institute of Medicine (IOM) at protein levels of 10-35% of total calories. The upper limit of the AMDR is to mitigate against osteoporosis, kidney stones and renal failure, which are all associated with high-protein intakes (IOM 2005). The IOM recommends a level of protein of 0.8 g/kg body weight. Thus a 70 kg man would be recommended to consume 56 g of protein, and a 60 kg woman would be recommended to consume 48 g of protein. The American Diabetes Association has gone further, and reduced this upper limit of AMDR, setting a recommended upper limit for daily protein of 20% of total calories for diabetics (Bantel 2006). The reason for this is because of the increased risk of renal failure with higher protein intakes. This translates as a maximum of 100 g a day for someone consuming 2000 calories a day or 75 g a day for someone consuming 1500 calories a day (substantially lower than the amounts of protein consumed on HPLC diets: the Atkins diet is approximately 160 g a day). As diabetes is an inevitable consequence of abdominal obesity and often late to be diagnosed, it is unwise for any obese patient to adopt a high-protein diet due to this potential to compromise renal function: diabetics are at a greater risk of kidney disease, and are extremely sensitive to the stress of a high-protein diet. One large trial involving 1,521 diabetic patients found that those who ate the most animal protein had lost over half of their kidney function, and almost all the damage was irreversible (Pedrini et al. 1996). Ideally patients should have their electrolytes measured before embarking on a lowcarbohydrate, high-protein diet, and any disturbance in electrolytes be considered as a relative contraindication. Renal insufficiency should be an absolute contraindication. Unfortunately blood tests are still not going to pick up most cases of deteriorating kidney function, as it can take many years of stress on the kidney before damage can be detected. Blood tests typically do not begin to detect problems until more than 90% of the kidneys have been destroyed (Fuhrman 2005). Renal stones and osteoporosis Animal protein consumption has long been recognised as a risk factor for both kidney stone formation and bone loss. It has been observed that there is increased calcium excretion the higher the sulphur amino acid content of dietary protein (Lemann 1999). Research reports that animal proteins cause calcium to be excreted in the urine with the consequence of a negative calcium balance. In contrast consuming soya protein instead of animal protein improves the calcium balance (Kaneko 1990). The mechanisms, some of which I shall outline below, are described in two studies, which gave high-protein diets firstly to human volunteers (Reddy et al. 2002) and secondly to rats (Amanzadeh et al. 2003). These two studies describe how kidney stones and osteoporosis are connected via mechanisms involving acid-base balance. There is an

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acidifying effect of animal proteins, due to the presence of a high proportion of the sulphur containing acids (2 to 5 times higher levels of methionine and cysteine than plant proteins), which are metabolised into sulphate and hydrogen, resulting in an acid ash (Breslau et al. 1988). High-protein diets also deliver an exaggerated acid load via increased production of uric acid, and in addition, a ketogenic low-carbohydrate diet will create ketoacidosis. To avoid a state of metabolic acidosis, the body compensates by increasing renal acid excretion and attempting to neutralise the acid by dissolving bone, which is alkali: phosphate is released which acts as a buffering agent to the excess hydrogen ions, and in the process calcium is also leached from the bones (PCRM 2012; Barzel 1995). Calcium is then lost in the urine: the calciuric response. As the sulphur content of the diet increases, so do the levels of calcium and acidity in the urine. Animal protein-induced calciuria has negative effects on bone health, due to this net renal calcium excretion. In contrast, plant proteins contain less sulphur containing amino acids and thus have less of an acidifying effect. Bone health is also compromised because high animal protein diets causing a high acid load, result in markedly increased osteoclastic bone resorption (breakdown) and reduced osteoblastic bone formation (Krieger et al. 1992). The rat experiment in which rats were fed either low (12%) or high (48%) milk protein (casein) diets for 59 days, resulted in an increase in bone resorption of more than 3-fold (Amanzadeh et al. 2003) in the high casein group. This bone loss contributes to the hypercalciuria and net calcium loss, increasing the propensity for both osteoporosis and calcium containing kidney stones. The net renal acid excretion also creates ideal conditions for kidney stone formation. In fact, the association of animal protein consumption with kidney stone formation has long been established (Kok 1990). The major factors for stone formation are hypocitraturia, hypercalciuria, hyperuricosuria and low pH, all consequences of consuming a high animal protein diet (Breslau et al. 1988; Reddy et al. 2002; Amanzadeh et al. 2003): there is an increased risk of crystallization of the stone-forming salts calcium oxalate and uric acid (the low pH causes uric acid to be sparingly soluble). Hypocitraturia can predispose to the formation of calcium containing stones because citrate is an inhibitor of the crystallization of calcium oxalate and calcium phosphate. Proof of the damaging consequences of HPLC diets is seen with the Reddy et al. human study, which looked at the metabolic effects the Atkins diet: the induction phase was for 2 weeks (consisting of protein 164 g and carbohydrate 19 g), followed by the maintenance phase for 4 weeks (consisting of protein 170 g and carbohydrate 33 g). The control group had a usual diet of 90 g of protein and 285 g of carbohydrate. Results on the effect on stone-forming propensity showed that on the Atkins diet, urinary pH and citrate values decreased significantly, whilst urinary acidity and net acid excretion increased more than 2-fold; urinary calcium levels increased substantially (by 60%); urinary saturation of calcium oxalate increased by 35%, and urinary content of undissociated uric acid doubled (Reddy 2002). The effects were all stronger on the induction phase compared with the maintenance phase. These stone-forming conditions occurred within days on the HPLC diet, so had the study been continued beyond 6 weeks, it would be expected to result in actual kidney stone formation.

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The damaging effect on bone by the HPLC diet is illustrated by the calcium balance decreasing during the induction phase by 130 mg/day and 90 mg/day on the maintenance phase, despite the calcium intake remaining approximately the same as the usual diet control group. As the intake of calcium was 805 mg, this HPLC diet actually caused a 16% loss of calcium a day. Another way of looking at it, an increase of 74 g of protein a day resulted in a loss of 130 mg a day of calcium: for every 1 g increase of dietary protein, there was a 1.76 mg loss of calcium in the urine. Furthermore, serum osteocalcin significantly decreased on the diet. Osteocalcin is used as a marker of bone formation: it is secreted solely by the bone-forming cells osteoblasts, stimulating bone building and bone mineralisation (Lee et al. 2007). Its connection with dietary intake is that it also acts on the body to secrete more insulin and causes the release of adiponectin in fat cells, thus increasing insulin sensitivity: on an HPLC diet this function would be expected to decrease, and hence it is compatible with the observed decline in osteocalcin levels. Not only did the HPLC diet cause calcium excretion and reduced osteocalcin levels, there was also an upward trend in markers of bone resorption. These results are supportive of previous research: in vitro experiments show that chronic metabolic acidosis enhances bone resorption and diminishes bone formation (Bushinsky & Frick 2000). Short-term controlled dietary studies in humans link high-protein diets with increased bone turnover (Kerstetter et al. 1999). Again, the type of protein is crucial: a metabolic study on skeletal metabolism in postmenopausal women detailed how acid retention from animal protein excess could impair bone formation and stimulate bone resorption (Sebastian et al. 1994). In the rat HPLC experiment, comparing a 12% casein diet with a 48% casein diet, the findings were replicated with even more marked detrimental effects, illustrating the damaging impact of a high sulphur (i.e. high animal protein) intake. (The major difference between the two diets was the sulphur content: the high casein diet had double the content of the low casein diet). The results were marked hypercalciuria, hypocitraturia, and increased urinary saturation of calcium phosphate with the high casein diet (Amanzadeh et al. 2003). Urinary calcium excretion was 2.7 to 3.6-fold higher, phosphate excretion 5 to 14-fold higher, and magnesium excretion 1.3 to 2.8-fold higher in the high casein group than the low casein group. As it was an animal experiment, it was possible to use histology to examine the effect on bone. The measurements of bone resorption, eroded surface and osteoclastic surface, were over 3-fold higher in the high casein group. Note that the calcium intake was exactly the same in the two groups, yet there was pronounced bone loss in the high casein group. Thus more calcium is lost in the urine on a dairy containing diet than is obtained from the dairy product. It should be remembered that dietary protein also increases the GFR, which further increases calcium excretion and adds to the calcium loss (Goldfarb 1994). The result is osteopenia (bone density is lowered by 1 standard deviation below that of an average 30 year old woman), which can later develop into the more severe osteoporosis, where the bone is prone to break (bone mineral density is 2.5 standard deviations below that of an average 30 year old woman). Osteoporosis is a serious condition, as it has a very high mortality: the cumulative

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mortality at one year after hip fracture is 37.1% for men and 26.4% for women (Kannegard et al. 2010). Deaths arise from both co-morbid conditions and complications due to the fracture itself. What does epidemiology show us on the link between protein intake and osteoporosis? The World Health Organisation has reported that animal protein is an important factor in the development of osteoporosis: â&#x20AC;&#x153;The paradox (that hip fracture rates are higher in developed countries where calcium intake is higher than in developing countries where calcium intake is lower) clearly calls for an explanation. To date, the accumulated data indicate that the adverse effect of protein, in particular animal (but not vegetable) protein, might outweigh the positive effect of calcium intake on calcium balance.â&#x20AC;?(WHO 2012). The highest rates of osteoporosis are in Sweden, Norway, Denmark and in US Caucasians (Kanis et al. 2002). These countries also have a high dairy intake, as seen in Table 6.1. Table 6.1. Dairy intake for Sweden, Norway, the UK and the USA Consumption per capita per year Milk litres Cheese kg Sweden Norway UK USA (all populations)

145.5 116.7 111.2 83.9

19.1 16 9.6 16

Source: International Dairy Federation Bulletin 423/2007 In the UK, 50% of women over the age of 50 will suffer a bone-thinning related fracture (van Staa 2002). In Sweden this figure is 46% (Kanis et al. 2000). In USA Caucasians, this applies to 40%, with 54% of menopausal women suffering from osteopenia, and 30% suffering from osteoporosis (Cummings & Melton 2002). The Inuit (Eskimos) have even worse rates, with an average of 10 to 15% less bone mass than US Caucasians (Pratt & Holloway 2001). This is despite a very high calcium intake of 2,000 mg a day (double the Western daily intake). They also consume a considerable intake of protein (250 to 400 g daily) from fish, whale and walrus. The lowest rates can be found in African Bantu women, who eat almost no dairy products at all, and have only 400 mg calcium daily. They live on a low-protein vegetable diet of 47g protein daily (Walker et al. 1972). In fact one American study found that women who drank two or more glasses of milk a day had a relative risk of 1.45 for hip fracture when compared with women consuming one glass or less a week (Feskanich et al. 1997). The Nurses Health Study reported that women who consumed at least 70 g of animal protein a day had a 22% greater risk of forearm fracture than those consuming less than 51 g (Feskanich et al. 1996). (Vegetable protein did not affect the risk). It was also reported that eating red meat 5 or more times a

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week increased the risk of forearm fracture by 23%, compared with eating red meat less than once a week. Another study demonstrated that elderly women with a high dietary ratio of animal to vegetable protein (over 3.17) had a more rapid rate of bone loss (by more than 3-fold), and a 3.7 times greater risk of hip fracture than do those with a low ratio (Sellmeyer 2001). These statistics have serious implications for traditional HPLC diets, containing mostly animal protein. As we age, the glomerular filtration rate falls, leading to the kidneyâ&#x20AC;&#x2122;s ability to excrete any excess acid load being diminished. Thus individuals develop progressively increasing blood acidity as they age. This further adds to the acid-producing effects of eating an animal protein diet, and increases the likelihood of osteoporosis in later life. Furthermore, sulphate ions bind calcium and prevent its tubular reabsorption in the kidney. Conversely, vegetable protein diets, which contain lower amounts of the acid forming sulphur amino acids, also contain base precursors: the metabolism of organic potassium salts produces ammonium bicarbonate. The net result is to enhance calcium retention in the body: there is less need for bone resorption as there is less need to buffer the acid load created by animal proteins. Thus there is less calcium excretion from the body on a vegan diet. Furthermore, soya is favourable to bone health. For example, soya isoflavones were demonstrated to inhibit bone resorption and stimulate bone formation, thus increasing bone mineral density, compared with placebo (Ma et al. 2008). In a randomised controlled trial, postmenopausal women receiving the soya isoflavone genistein had decreased levels of deoxypyridinoline, a marker of bone resorption, and increased levels of bone-specific alkaline phosphatase, a marker of bone formation (Marini et al. 2007). Good plant-based sources of calcium include dark green leafy vegetables, such as cabbage, kale and broccoli, pulses (especially chick peas and tofu), dried fruits (especially figs), nuts (especially almonds) and seeds (especially sesame seeds), and calcium enriched soya milk. Other calcium rich vegetables include green beans, carrots, celery, leeks, onions, parsnips. Calcium absorption is actually higher for broccoli (5060%) than for milk (30-35%) (Weaver et al.1999). The fruits that are richest in calcium include raspberries, oranges, kiwi, blackcurrants and blackberries. There are many different nutrients apart from calcium associated with good bone health. Intakes of potassium, magnesium, beta carotene, vitamin C and fibre all have beneficial effects on bone mass: one study reported reduced concentrations of urinary pyridinoline and deoxypyridinoline (markers of bone resorption) and enhanced bone mineral density with intake of these nutrients, in women aged 45 to 55, even after controlling for age, weight, height and menstrual status (New et al. 2000). These nutrients are all found in abundance in fruit and vegetables. Indeed it was reported that there was a positive association between fruit intake in early life and bone mineral density. Other studies have shown increased bone mineral density with increased fruit and vegetable consumption, in postmenopausal women (Chen et al. 2006) One important trace element which helps to prevent calcium loss and maintain bone mineral density is boron. It also has important roles in blood, joint and brain health. Inadequate dietary boron, even in the short-term, leads to poor cognitive performance and

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brain function (Expert Group on Vitamins and Minerals 2002). This essential nutrient is present in high amounts in dried fruit, plums, apples, pears, grapes, nuts, peanuts, leafy vegetables, potatoes and legumes, whereas animal products are very poor sources. Any HPLC diet should include plentiful amounts of these boron-rich plant foods. All of the above evidence illustrates how HPLC diets can cause loss of body calcium, leading to osteopenia and osteoporosis, and also increase the risk of kidney stones, unless plant-based protein is substituted for animal protein.

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7. BOWEL FUNCTION Constipation Meat, fish and dairy contain no fibre at all, so there is a strong risk of constipation on a high animal protein diet, especially if whole grains and fruit (as in HPLC diets) are avoided. In fact the reported rate of constipation on HPLC diets is 68% (Yancy et al. 2004). Not only is this uncomfortable, long-term, it can also lead to serious complications of diverticulitis and bowel cancer. Lactose intolerance and allergy Most infants have the ability to digest lactose, the sugar in milk. However, after the age of two, many lose this ability due to the loss of the enzyme lactase: with the consumption of milk, lactose builds up in the small intestine, is fermented by bacteria, and the build up of gas causes nausea, pain, bloating, wind and diarrhoea. Most people in the world are lactose intolerant, depending on ethnic group (Table 7.1) (Butler 2006) Table 7.1. Prevalence of lactose intolerance according to ethnic group 95% of Asians 75% of Afro-Caribbeans 50% of Mediterraneans 10% of Northern Europeans As the people seeking weight loss advice in my London clinics include a large proportion of non-Northern Europeans, this is an important reason to develop a diet more suitable for them, with greatly reduced dairy produce. Cowâ&#x20AC;&#x2122;s milk proteins are amongst the most common causes of food allergy in infants (Munoz et al. 2004). In individuals with milk allergy there is also a strong correlation with beef and pork allergy (Mamikoglu 2005). Thus milk allergic patients may also have to avoid cowâ&#x20AC;&#x2122;s and pork meat. Not only are dairy products a common cause of allergy, but cheese is also the third most common cause of food-induced migraine in adults, after alcohol and chocolate (Glover 1983). These are all factors to be considered when evaluating an HPLC diet containing dairy products. Autoimmune disease, intestinal microflora and leaky gut Cowâ&#x20AC;&#x2122;s milk proteins are a known factor in leaky gut syndrome. The mechanism of leaky gut syndrome is that the tight junctions between the intestinal cells widen, letting in undigested food particles and toxins which would normally stay in the lumen of the gut.

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These particles then cause an inflammatory response in the body, which can cross react with the body's own organs. Leaky gut is associated with many chronic degenerative diseases such as type 1 diabetes, coeliac disease, rheumatoid arthritis, ankylosing spondylitis, Crohn's disease, ulcerative colitis, irritable bowel syndrome and atopic conditions such as asthma, rhinitis and eczema (Liu et al. 2005). The intestinal barrier is not intact until the age of one, so if an infant is not exclusively breast fed, macromolecules found in cows' milk such as bovine beta casein can easily permeate through the intestinal wall. Bovine beta casein has sequence homologies with a beta cell antigen in the pancreas: the structure of milk protein amino acid chains is identical to the surface structure of the insulin producing cells. It has been proposed that early exposure to cow's milk triggers an anti-casein immune response, which then attacks the beta cell antigen, resulting in defective insulin production and type 1 diabetes (Cavallo et al. 1996). Numerous studies have shown a positive correlation between bovine beta casein consumption and type 1 diabetes, and the presence of antibodies to bovine beta casein, and type 1 diabetes (Elliott et al. 1999; Monetini et al. 2002). Other cowâ&#x20AC;&#x2122;s milk autoantibodies have been implicated in the pathogenesis of type 1 diabetes. Autoantibodies to bovine serum albumin are much higher in children with type 1 diabetes than in non-diabetic children (Hammond-McKibben & Dosch 1997). One study examined the effect of giving cow's milk formula to 91 infants with a first degree relative with type 1 diabetes (Luipajarvik et al. 2008). 8 of these children went on to develop type 1 diabetes by the age of 7. Analysis of the blood revealed autoantibodies to beta lactoglobulin, cow's milk formula and bovine insulin in those affected with type 1 diabetes compared with those without the disease. Thus beta cells are destroyed as well as insulin itself in children with early exposure to cow's milk formula: the gut has yet to mature and form tight junctions, so large amino acid chains from the cow's milk proteins are absorbed and are able to stimulate an immune response. Other autoimmune diseases such as coeliac disease also demonstrate this correlation between dietary protein intake and stimulation of the immune system. In autoimmune conditions such as eczema, asthma, inflammatory bowel disease, irritable bowel disease, type 1 diabetes, coeliac disease and allergies, where there is a relationship with the presence of leaky gut, symptoms can be improved through treatment with probiotics: beneficial bacteria such as bifidobacteria and lactobacilli (Fasano & SheaDonohue 2005). This is because beneficial bacteria (probiotics) reverse increased intestinal permeability by stabilization of the gut mucosal barrier (Laitinen & Isolauri 2005). Furthermore, studies have shown unfavourable alterations in intestinal microflora in all of the above autoimmune diseases, and this is now thought to be a significant contributing causal factor. "Good" bacteria, such as gram positive bifidobacteria and lactobacilli, need complex carbohydrates to feed on and thrive: so called prebiotics. These are only contained in a carbohydrate diet rich in fermentable dietary fibres (nondigestible oligosaccharides). Fructo oligosaccharide, a valuable source of inulin (long chain fructose), and

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oligofructose (short chain fructose), are important prebiotics. The relevance to HPLC diets is that prebiotics are only found in carbohydrate foods. Thus on a low-carbohydrate diet, a detrimental imbalance in intestinal microflora occurs, with a depletion in carbohydrate-fermenting “good” gram positive probiotic bacteria, and overgrowth of protein-putrefying “bad” gram negative bacteria such as Escherichia. Any leaky gut symptoms will be worsened as the gut mucosal barrier relies on the presence of probiotics to heal the widened junctions. This deleterious effect is proved in one study which looked directly at the effect of a 4 week HPLC diet on microflora in human volunteers (Duncan et al. 2006). Each of the three groups was assigned to consume levels of carbohydrate of 399 g, 164 g or 24 g a day. This corresponded to faecal bifidobacteria levels of 4%, 2.1% and 1.9% respectively, and this decrease in probiotic level would be expected to be correlated with a decrease in their many important functions. To illustrate the effect of HPLC diets on leaky gut-associated degenerative disorders, inflammatory bowel disease is a good example: it has been found that there is a strong association with animal protein intake. A French study on 67,581 middle aged women found that of those diagnosed with inflammatory bowel disease after 10 years follow up, 90% were consuming more than the recommended amount of protein (Jantchou et al. 2010). The increased risk was for animal protein only (meat and fish). The authors proposed that the reason could be due to the toxic end products of meat and fish digestion such as hydrogen sulphide and ammonia. They also proposed that a high-protein diet alters the balance of bacteria in the colon, with an overgrowth of pathogenic bacteria and a depletion in probiotic bacteria. Short chain fatty acids, which result from probiotic fermentation of soluble fibre, nourish epithelial cells in the gut, thus promoting intestinal health. Furthermore, the consequent acidic environment in the gut causes an inability to thrive for sulphate-producing bacteria, resulting in a reduction in toxic hydrogen sulphide gas. A Japanese study examined the relapse rates in patients with Crohn’s disease by comparing two different diets: one group ate a semi-vegetarian diet of brown rice, soya, fruit and vegetables, with minimal amounts of egg and yogurt, and a very small portion of fish once a week, and a very small portion of meat once every two weeks (Chiba et al. 2010). The control group was omnivorous, eating meat and fish freely. After two years, the remission rate in the semi-vegetarian group was 92%, compared with only 25% in the omnivorous group. Furthermore, levels of C-reactive protein, a marker of inflammation, was normal in more than half of the semi-vegetarian patients. The authors linked the results to diets rich in animal protein and animal fat causing a decrease in beneficial bacteria in the intestine. Indeed, many studies have demonstrated an imbalance in colonic bacteria in inflammatory bowel disease: an increase in protein putrefying bacteria such as Escherichia coli and Bacteroides, and a decrease in carbohydrate fermenting Bifidobacterium spp. (Kennedy et al. 2002; Linskens et al. 2001). The archetypal inflammation-inducing microflora is associated with the typical Western diet: early research shows an imbalance of microflora in diets rich in animal fats and

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protein, compared with the rural Japanese diet (rich in grains, fruit and vegetables) (Benno 1986). The latter study demonstrated an increase in pathogenic bacteria such as Bacteroides and Clostridium spp., with a decrease in probiotic bacteria such as Bifidobacterium and Lactobacillus spp. in the Western diet, compared with the opposite state in the rural Japanese diet. Other research supports the link between animal protein and inflammatory bowel disease, and the protective effect of prebiotic carbohydrates: a UK study which included 218 patients with Crohnâ&#x20AC;&#x2122;s disease, found a 40% higher risk of developing it in meat eaters compared with vegetarians. Conversely, fruit consumption was associated with a 22% less chance of developing Crohn's disease (Abubukar et al. 2007). Conversely consumption of prebiotics or probiotics is associated with improvements in the symptoms of inflammatory bowel disease, by restoring a predominance of beneficial Lactobacilusi and Bifidobacterium spp. (Mcfarlane et al. 2005; Sartor 2004; Ishikawa et al. 2003; Hedin et al. 2007). One can conclude that HPLC diets increase the risk of developing inflammatory bowel disease due to the high levels of meat and low levels of prebiotic carbohydrates. The most effective prebiotic foods are rich in oligofructose and inulin. Analysis of such foods is detailed in Table 7.2 (Moshfehg et al. 1999). Table 7.2. Foods rich in the prebiotics inulin and oligofructose Chicory root Jerusalem artichoke Leeks Onions, cooked Wheat bran, raw Wheat flour, baked Asparagus Banana Rye, baked Barley, cooked

Inulin g/100g 41.6 18 6.5 3 2.5 2.4 1.7 0.5 0.7 0.2

Oligofructose g/100g 22.9 13.5 5.2 3 2.5 2.4 1.7 0.5 0.7 0.2

70% of the food source of oligofructose and inulin on Western diets comes from wheat, and 25% from onions (Moshfegh et al. 1999), so on a wheat-free HPLC diet, the levels of these important prebiotic foods are drastically reduced. Some examples of prebiotic rich foods are listed in Table 7.3, arranged in a specific order to highlight the deficiencies of HPLC diets. Note that the last ten foods are all absent in HPLC diets for the initial stages, and absent in or severely limited in later stages. In an extreme HPLC diet such as the Dukan diet, none of the listed prebiotic foods are allowed in the first stage, which lasts up to ten days.

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Table 7.3. Prebiotic foods allowed or absent on HPLC diets Prebiotic food allowed on HPLC diets (apart from the Dukan initial phase, on which all plant food is banned) artichokes garlic, shallots, onions, chives, leeks asparagus tomatoes Prebiotic food banned on HPLC diets: chicory wheat bran wholewheat flour soya potatoes beetroot raw oats brown rice rye barley bananas (adapted from Mouton 2005) What are the mechanisms for probiotic gut microbiota reducing gut permeability and improving the gut barrier function? One potential explanation arises from the observation that Bifidobacterium spp. maintain the gut barrier. Unlike pathogenic bacteria, they do not degrade intestinal mucus glycoproteins (Ruseler-van Embden et al. 1995). Furthermore they promote healthier microvilli by increasing villus height and crypt depth, which leads to a thicker mucosal layer in the jejunum and colon (Kleessen et al. 2003). These effects are related to short chain fatty acids such as butyrate, produced as a result of bacterial fermentation of carbohydrate. Butyrate acts as an energy source for colonocytes and has a trophic effect on the mucosa (Bartholome et al. 2004). Other probiotic strains such as lactobacilli also demonstrate protection of the epithelial barrier function (Johnson-Henry et al. 2008). Gut permeability is controlled by several specific tight junction proteins, in particular ZO-1 and occludin. Studies have reported that prebiotic feeding (fermentable nondigestible carbohydrate) increases ZO-1 and occludin in the small intestine, along the apical cellular border. Another controlling factor in gut permeability is glucagon-like peptide 2 (GLP-2). This has an intestinotrophic effect, enhancing intestinal epithelial proliferation and reducing gut permeability (Cameron & Perdue 2005). GLP-2 is derived from proglucagon in the endocrine L cells lining the jejunum and proximal colon.

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Prebiotic feeding has been shown to increase proglucagon mRNA, and increase levels of GLP-2. Furthermore, prebiotic treatment improves tight junctions, promotes proliferation of epithelial cells and lowers intestinal permeability, thus improving the gut barrier function (Cani et al. 2009a). It has been demonstrated that obesity itself causes changes in gut flora, which in turn is associated with increased intestinal permeability (Brun et al. 2007). For example obese mice exhibit an altered gut barrier, characterised by disruption of tight junction proteins. Furthermore, obese mice have higher levels of inflammatory cytokines such as TNF alpha and IL-6, which are known to have a deleterious effect on tight junctions. In addition, a high-fat carbohydrate-free diet decreases levels of Bifidobacterium spp. and strongly increases intestinal permeability by reducing the expression of the genes coding for the tight junction proteins (Cani et al. 2008). Thus an HPLC diet would be expected to worsen the obesity-induced compromised gut barrier function and potentiate symptoms of leaky gut. The importance of prebiotics (i.e. including plenty of fibrous carbohydrate in the diet) is demonstrated by the Cani et al. 2009a study, which discovered that obesity-induced changes were reversed with prebiotic treatment: it showed that gut permeability and plasma cytokine levels were both significantly lowered and hence improved, on feeding obese mice with prebiotics (Cani et al. 2009a). I will focus later in detail on some of the roles of intestinal microflora in relation to appetite, fat mass and diabetes, but to summarise the many important roles of intestinal microflora (adapted from Mouton 2008): 1. Supplying essential micronutrients such as vitamins B1, B2, B5, B8, B9 (folate), B12, and vitamin K (Hill 1997). For example it has been demonstrated that Pseudomonas and Klebsiella spp. may synthesize significant amounts of vitamin B12 (Albert et al. 1980). This would provide a good supply for those following an exclusively plant-based diet. 2. Conserving nitrogen: recycling urea into amino acids, and decreasing ammonia production and absorption. This is the reason why the prebiotic lactulose is given to patients with hepatic encephalopathy, to reduce levels of neurotoxic ammonia (Solga & Diehl 2004). 3. Stabilizing the intestinal ecosystem in terms of pH and hydration. Fermenting bacteria produce a healthy acidic intestinal environment (lower pH), due to the production of short chain fatty acids from carbohydrate. In contrast, putrefying bacteria cause a raised pH due to the conversion of amino acids into ammonia. 4. Completing enzymatic digestion of e.g. lactose, proteins, cellulose.

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5. Producing short chain fatty acids e.g. butyrate. These are absorbed and utilised by the host, improving glucose tolerance, reducing appetite, and protecting against diabetes. They also have anti-cancer properties. 6. Producing molecules with antibiotic activity. 7. Controlling the development of potentially pathogenic species, as there is competition between different bacteria for energy sources and binding sites to the mucosa. 8. Providing important immune stimulation through GALT modulation: stimulation or repression according to the microflora composition. Probiotics can stimulate the secretion of IgA which protects mucosal surfaces against harmful bacterial invasion. 9. Providing important trophic effects on intestinal epithelia, thus repairing the damage of leaky gut, a condition of increased intestinal permeability and associated with allergies and autoimmune conditions. 10. Processing bilirubin in biliary pigments: urobilinogen and urobilin, stercobilinogen and stercobilin. Not only do prebiotics promote probiotic bacteria such as Bifidobacterium and Lactobacillus spp., thus facilitating the functions of probiotics as mentioned above, they also have other beneficial effects, as summarised here: 1. They stimulate the absorption of calcium, magnesium, zinc and iron, and improve the mineralisation of bone (Scholz-Ahrens et al. 2001; Abrams et al. 2005). 2. They are appetite suppressants. 3. They have anti-diabetic properties 4. They lower plasma cholesterol and triglycerides. 5. They reduce the accumulation of fats in the liver, thus helping in the condition of nonalcoholic steatohepatitis, common in obesity, and linked to the development of type 2 diabetes. 6. They stimulate the colonic production of short chain fatty acids, resulting in reduced mucosal inflammation and decreased mucosal lesional scores (Guaner 2005). Short chain fatty acids also have anti-cancer properties, as demonstrated by the anti-cancer properties of prebiotics such as chicory inulin and oligofructose (Manning & Gibson 2004; Pool-Zobel et al. 2002).

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Short-chain fatty acids The fermentation products of prebiotics on soluble fibre are short-chain fatty acids. They have a number of important roles, contributing to the health promoting physiological processes of pre and probiotics, including (Wong et al. 2006; Mouton 2008): 1. They stabilise blood glucose levels by acting on pancreatic insulin release and liver control of glycogen breakdown; they also stimulate gene expression of glucose transporters in the intestinal mucosa. Thus they enhance insulin sensitivity and have an anti-diabetic action. 2. They suppress cholesterol synthesis by the liver and reduce blood levels of LDL cholesterol and triglycerides, thus helping to combat cardiovascular disease. 3. They have a number of anti-cancer actions: - providing nourishment for colonocytes and enhancing cell differentiation and apoptosis of pre-cancerous colonocytes. - lowering the pH of the large bowel, thus reducing the transformation of primary bile acids into secondary bile acids, which are carcinogenic. 4. They stimulate the production of T helper cells, leukocytes, antibodies and cytokines thus improving immune function. 5. They improve the barrier properties of the colonic mucosal layer, preventing the entry of gut antigens into the tissues, which cause inflammation and immune dysfunction. 6. They enhance the absorption of dietary minerals. 7. They act as appetite suppressants. Prebiotics and probiotics in relation to weight Appetite How do prebiotics (nondigestible oligosaccharides) affect weight? Prebiotics have been shown to reduce appetite, the hunger hormone ghrelin and food intake, and to increase satiety hormones such as plasma peptide YY (PYY) and GLP-1 in both rats and humans. For example, PYY, which has an appetite suppressant effect and slows gastric emptying, increases in rats fed prebiotics (Cani & Delzenne 2009). In humans, prebiotic administration causes a reduction in caloric intake and weight loss. One study followed overweight volunteers given either 21 g of oligofructose a day or a placebo for 12 weeks (Parnell & Reimer 2009). No other dietary or exercise interventions were performed. The results revealed that the prebiotic group ate 29% less than the control group, and lost weight in the form of fat around the trunk. The control group actually gained weight. The

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positive outcomes of the prebiotic group were associated with an increase in the satiety hormone PYY by 13%, and a reduction in the hunger hormone ghrelin by 23%. Shorter term human studies also demonstrate a beneficial rise in satiety hormones on administration with prebiotics: 20 g a day of oligofructose led to an increase in circulating GLP-1 after only one week (Piche et al. 2003). After 13 days of 16 g a day of oligofructose, PYY and GLP-1 were both significantly raised compared with 10g a day or placebo (Verhoef et al. 2011). Furthermore, energy intake was significantly reduced by 11%. Inulin-type fructans modulates gastrointestinal peptides involved in appetite regulation in rats: after 8 hours of food deprivation, active ghrelin (the "hunger hormone") is significantly lower in oligofructose and inulin fed rats than controls, and glucagon-like peptide-1 (GLP-1) is doubled (thus increasing satiety) (Cani et al. 2004/2005). The mechanism is mediated by bacterial fermentation producing short chain fatty acids, which then increase the level of proglucagon in the intestinal L cells. The expression of the proglucagon gene leads to the secretion of the satiety hormone GLP-1, which in turn reduces ghrelin secretion. Indeed, prebiotic feeding in mice decreases food intake, which is associated with lower visceral and subcutaneous adipose depots and a higher muscle mass (Cani et al. 2009b). This study found that oligofructose added to a high-fat carbohydrate-free diet led to a rise in circulating GLP-1 levels, a reduced fat pad weight by 40% and substantially reduced weight gain, compared with mice fed the same high-fat diet but without any prebiotics. In human obesity, plasma GLP-1 and PYY are reduced, and this impaired secretion hinders weight loss (Ranganath et al. 1996; Batterham et al. 2002). It is clear that any individual wishing to lose weight would be advised to include plenty of prebiotic carbohydrate foods, due to their proven effects on increasing GLP-1 and PYY, on reducing food intake, and on fat loss â&#x20AC;&#x201C; food either absent or restricted on HPLC diets. Energy harvest Obese individuals have been found to have certain characteristic microbial communities compared with normal weight individuals. This is an important factor in energy homeostasis, as the observed increase in certain types of bacteria results in more efficient energy extraction from food (Di Baise et al. 2008). When obese people lose weight, the microflora reverts to that found in normal weight individuals. The significance of the role of the microflora in the development of obesity is highlighted by a microbiota transfer study. Interestingly, germ-free mice given caecal microbiota from obese mice gained large amounts of body fat compared with the mice given caecal microbiota from lean mice (Turnburgh et al. 2006). Research in children reveals that the microflora composition of infants predicts whether they will develop obesity as they grow older (Kalliomaki et al. 2008). This study reported

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that infants who remained normal weight at age 7 had over 3 times the levels of Bifidobacterium spp., compared with infants who became overweight. The overweight children were also found to have much higher levels of Staph. aureus bacteria as infants. One way to increase Bifidobacterium levels in infants is to feed them breast milk, rich in oligosaccharides. In adults, Bifidobacterium spp. levels increase with the intake of fibrous carbohydrates (prebiotics), deficient in HPLC diets. A diet lacking in polysaccharides such as in cases of fasting or a low-carbohydrate diet, leads to the adaptation of Bacteroides thetaiotaomicron. This is a very successful glycophile with a prodigious capacity for digesting otherwise indigestible dietary polysaccharides i.e. it can digest any carbohydrate. It even turns to host mucus (mucins and glycosphingolipids) in order to produce monosaccharides (Sonnenburg et al. 2005). Thus any individuals with an excess of this bacteria actually gain weight as all carbohydrate is digested, even if it is derived from their own mucosa. This has important implications for the devising of weight loss diets, which should include complex carbohydrate (polysaccharides) to prevent such bacterial adaptation and subsequent increased energy harvest. Metabolic actions of endotoxin producing bacteria Obesity and insulin resistance are associated with a low grade chronic inflammation, with adipose tissue presenting increased expression of proinflammatory cytokines such as TNF, IL-1 and IL-6. These cause inactivation of insulin receptors in muscle, resulting in insulin resistance, hyperinsulinaemia, hyperglycaemia and excessive hepatic and adipose tissue lipid storage: features of metabolic syndrome and type 2 diabetes. I have discussed earlier the role of saturated fatty acids in triggering this inflammation: they induce inflammatory signaling in adipocytes and macrophages through activation of the TLR4 receptor (Kennedy et al. 2009). However, there is another important factor in glucose homeostasis and the triggering of inflammation: microbial ecology. This hypothesis arose from the observation that highfat feeding promoting obesity and diabetes is associated with a metabolic endotoxemia (Cani et al. 2007a). Endotoxemia is defined as elevated levels of endotoxins in the blood. An endotoxin is a toxin found in the outer membrane of various gram negative bacteria, which is recognised by the immune system. It consists typically of a lipopolysaccharide (LPS): a polysaccharide chain (harmless) with an attached lipid segment called lipid A, which is responsible for the toxic effects. Clinical manifestations of endotoxemia include fever, activation of inflammation, and increased coagulation, as seen for example in meningitis. With higher plasma concentrations of endotoxin (around 2 to 3 times more than normal), a metabolic endotoxemia is observed. LPS is transported from the gut in plasma chylomicrons (lipoproteins), having been freshly synthesised by epithelial intestinal cells, in response to dietary fat. The LPS triggers the CD14 receptor in target tissues, which sets off the inflammatory and metabolic cascade. The result is dysregulation of the inflammatory tone, visceral adipose tissue inflammation, hepatic inflammation with

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steatosis, systemic inflammation, oxidative stress, macrophage infiltration, endothelial cell activation, early events of atherosclerosois, insulin resistance, diabetes, and fat mass increase (Cani et al. 2007a/2008). The fact that LPS has an atherogenic role is based on observations that increased LPS levels correlate with increased atherogenic risk; LPS upregulates atherogenic gene expression; and LPS injected into mice and rabbits causes the formation of plaques (Erridge et al. 2007). All these inflammatory reactions are characteristic of those found in metabolic syndrome. In humans, just one high-fat meal is enough to induce an acute metabolic endotoxemia, leading to LPS increases which can activate monocytes (Erridge et al. 2007). The mechanism is due to the cotransit of LPS with dietary fat. A high-fat meal of 50 g of butter, spread onto toast, given to healthy normal weight volunteers, resulted in peak LPS concentrations 40 minutes postprandially, which correlated with triacylglycerol concentrations. This study underlines the importance of consuming a low-fat diet, to minimise the transport of LPS from the gut to the rest of the body, thus triggering off the inflammatory cascade characteristic of the metabolic syndrome i.e. the opposite of an HPLC diet, which is high in fat. A chronic state of endotoxemia can occur in the case of regular high-fat feeding and obesity itself: these states induce a change in gut flora, which both increases the number of LPS containing gram negative bacteria and also increases gut permeability (as discussed earlier). This chronically increases LPS absorption from gram negative bacteria, resulting in endotoxemia, inflammation and metabolic disorders (Cani et al. 2008). Indeed, high-fat carbohydrate-free feeding results in endotoxemia in mice. After 4 weeks on a diet consisting of 72% fat, 28% protein and no carbohydrate, obesity and diabetes were induced, with a 3-fold increase in plasma LPS, an increase in LPS containing gram negative microbiota in the gut, and a decrease in Bifidobacterium spp. (Cani et al. 2007a). Analysis of the liver found an increase in hepatic triglycerides. Note that this diet could be termed a high-fat HPLC diet. The implications of this research are that HPLC diets result in a detrimental change in microflora, increased gut permeability, enhanced generation of endotoxins and transport into the plasma, with subsequent endotoxemia, systemic inflammation, oxidative stress, hepatic steatosis, insulin resistance, endothelial cell activation and atherosclerosis. Combined with the observed reduction in anti-cancer metabolites on HPLC diets, the net result is an increased risk of type 2 diabetes, cardiovascular disease and cancer. Antidiabetic actions of prebiotics GLP-1 has numerous anti-obesity actions including inhibition of food intake, delaying gastric emptying and causing weight loss. It also has anti-diabetic actions: it stimulates insulin secretion, inhibits glucagon secretion, stimulates beta cell proliferation in the pancreas, increases insulin sensitivity and decreases glycaemia (Parnell & Remer 2009). Prebiotics such as oligofructose stimulate GLP-1 secretion, as established earlier, so including prebiotics in the diet of an obese subject reduces the risk of developing diabetes.

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One study on mice fed a high-fat, carbohydrate-free diet, quickly led to features of type 2 diabetes, with insulin resistance, glucose intolerance and reduced glucose-stimulated insulin secretion. However the addition of oligofructose to the diet, which increased Bifidobacterium spp, reversed these metabolic changes and normalised inflammatory tone. There was an observed improvement in glucose tolerance, endotoxemia, fasting blood glucose, glucose-stimulated insulin secretion, and insulin-sensitive hepatic glucose production compared with the prebiotic-free mice (Cani et al. 2007b). Human studies also demonstrate this anti-diabetic effect of prebiotics: the Parnell & Remer 2009 study on oligofructose supplementation showed that after 12 weeks the prebiotic group decreased blood glucose and insulin. Hence prebiotic carbohydrates improve glucose regulation. Another human study found that a barley-based evening meal, rich in soluble fibre, increased plasma butyrate the next morning, which corresponded with a reduced postprandial glucose response after breakfast (Nilsson et al. 2010). This result supports the view that indigestible carbohydrates improve glucose tolerance through a mechanism involving colonic fermentation, and may be one explanation of how whole grain is protective against type 2 diabetes and cardiovascular disease. Fatty liver and cholesterol Obesity is associated with the accumulation of triglyerides in the liver, resulting in the condition of non-alcoholic hepatosteatosis (â&#x20AC;&#x153;fatty liverâ&#x20AC;?). This can cause inflammation and hepatic dysregulation, resulting in non-alcoholic steatotohepatitis. Left unchecked, the inflammation can progress to cirrhosis and liver failure. There is a link with gut microflora, as high-fat, carbohydrate-free feeding (thus inducing metabolic endotoxemia) is associated with raised hepatic triglycerides (Cani et al 2007a). Indeed there is a positive correlation between the level of breath acetone (a ketone body by-product of a ketogenic diet) and the presence of non-alcoholic fatty liver disease (Solga et al. 2006). Thus one mechanism for hepatic steatosis is via the increase in LPS, triggering inflammation in the liver. Probiotic feeding reduces endotoxemia as explained before, and reduces hepatic inflammation and steatosis. Another important function of prebiotics is to lower cholesterol and triglycerides: studies in rodents show that inulin and oligofructose can reduce plasma levels of cholesterol and triglycerides (Beylot 2005). One of the mechanisms is that prebiotics increase plasma GLP-1, as explained before, which in turn stimulates insulin release and insulin sensitivity. This then has the effect of increasing lipid synthesis and decreasing lipolysis, thus reducing plasma lipid levels. In addition prebiotics can oppose triglyceride accumulation in the liver and have favourable effects on hepatic steatosis. The effect is due mainly to expression and activity of liver lipogenesis, resulting in a lower hepatic secretion rate of triglycerides (Beylot 2005). All these functions will be compromised on a low-carbohydrate diet, due to the lack of carbohydrate substrate for the good bacteria to feed on.

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It is well known that people living a Western lifestyle have a significantly reduced flora, compared with those who live in rural areas who consume large amounts of fruit and vegetables. It is also known that intestinal microflora deteriorates with age, with the elderly displaying reduced amounts of fermenting good bacteria such as Bifidobacterium spp., and increased amounts of the putrefying bad bacteria such as Clostridium spp. (with a corresponding increase in faecal pH) (Hopkins et al. 2002; Hebuterne 2003). This change in microflora may be related to increased risk of disease in the elderly. Stress, via an increase in catecholamines, is another factor resulting in dramatic increases in pathogenic gram negative bacteria, such as Bacteroides thetaiotaomicron and Escherichia coli (Lyte & Ernst 1992; Holdeman et al. 1976). Stress also causes a significant decrease in beneficial Lactobacillium spp. (Bailey & Coe 1999). I would question the promotion of a diet lacking in important prebiotics to older patients, or those suffering from stress (a large proportion of the population!) The above research demonstrates the importance of including enough fibrous carbohydrate in the diet to provide prebiotics for probiotic bacteria to thrive. HPLC diets are severely depleted in prebiotics, and instead provide excessive protein and fat for putrefying pathogenic bacteria to proliferate. Consequences such as leaky gut, endotoxemia, systemic inflammation, hepatic steatosis, insulin resistance, atherosclerosis, and the generation of carcinogenic metabolites ensue. Conversely, fibrous carbohydrates rich in prebiotics have the opposite effect, in addition to increasing cancer-protective faecal butyrate concentrations, improving mineral absorption, and stimulating the satiety hormones PYY and GLP-1 (which also improves insulin sensitivity and cholesterol levels). Irritable bowel syndrome Taking irritable bowel syndrome (IBS) as an example, it has been shown that the faecal microbial flora composition in these patients has reduced Lactobacillus and Bifidobacterium spp. (both of which ferment carbohydrate) compared with healthy controls (Balsari et al. 1982). This has relevance to me personally, as I followed an HPLC diet a few years ago, eating cottage cheese, yogurt, Quorn, vegetables and one fruit a day. I ended up in hospital for 3 days with acute abdominal pain, secondary to horrendous constipation and irritable bowel syndrome. In fact IBS and constipation continued to plague me for several years until I switched to soya milk, cut out dairy products, and increased my fruit, whole grain and pulse intake. My abdomen is now much flatter and I have no more pain. I have also managed to maintain a BMI of 19.5. Conclusion: one can be slim and healthy and eat carbohydrates! All one needs to do is cut out anything containing sugar and white refined products, and eat plenty of fibrous complex carbohydrates instead.

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8. MENTAL FUNCTION When examining the effect of diet on mood, one study found that vegetarian diets were significantly associated with healthier mood states than omnivores (Beezhold et al. 2010). This was associated with a higher intake of the short chain omega 3 fatty acid, alpha linolenic acid, (by 1.7 times), and a 9 times lower intake of the omega 6 fatty acid arachidonic acid in the vegetarians. This is consistent with the finding that vegetarians have higher circulating antioxidants and reduced levels of oxidative stress (Krajcoviccova-Kudlackova et al. 2007). What is the mechanism for oxidants and other inflammatory agents causing mental health problems? Arachidonic acid is a potent mediator of pro-inflammatory stress in the brain, acting as a precursor to inflammatory eicosanoids and cytotoxins. High levels of arachidonic acid are harmful and are associated with neurodegenerative disease and neuroinflammation (Farooqui et al. 2007). Furthermore, haem iron found in meat is a potent pro-oxidant. Evidence from human biochemical, genetic, and pharmacological data, clinical trials, therapeutic studies and animal models supports the role of oxdiative stress in the pathology of diverse psychiatric disorders such as schizophrenia, depression, bipolar disorder, anxiety disorders, autism and attention deficit disorders (Ng 2008). Thus any HPLC diet high in haem iron or arachidonic acid would be expected to increase oxidative damage and cause neuroinflammation in the brain, resulting in an increased risk for many different central nervous system diseases. Alzheimer's disease and cognitive function Alzheimer's disease is associated with diets high in omega 6 fatty acids, cholesterol and saturated fatty acids. There are several different mechanisms, including beta-amyloid deposition and increased brain inflammation. For example, oxidative breakdown products of omega 6 fatty acids and cholesterol (oxysterols) have been found to promote betaamyloid deposition in the brain (Corsinovi et al. 2011). Another mechanism is that the saturated fatty acids found in meat (palmitic acid and stearic acid) activate the inflammatory pathways that trigger neuronal death: this is through the activation of microglial cells, which secrete pro-inflammatory mediators, having a lethal effect on brain cells. In vitro experiments have demonstrated that palmitic acid and stearic acid initiate microglial activation, with subsequent increased release of reactive oxygen species, nitrous oxide and pro-inflammatory cytokines, all of which trigger primary neuronal death (Wang et al. 2012). The changes occur through increases in the mRNA level of pro-inflammatory mediators, and stimulation of the toll-like receptor/nuclear factor kappa beta pathway (TLR-4/NF-kappa B): the same pathway involved in the process of the saturated fat-mediated inflammation associated with insulin resistance and metabolic syndrome, as discussed earlier. There appears to be a link between insulin function and cognitive function: brain insulin receptors are widely distributed at high levels in neurons, and insulin is known to regulate

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processes such as cell survival and neurite extension. Insulin receptors in the hippocampus and cerebral cortex are involved with increasing the efficiency of synaptic transmission, learning, and memory (particularly long-term memory consolidation) (Zhao et al. 2004). In fact, the temporal lobe (which includes the hippocampus) and the cerebellum require intact insulin signaling mechanisms to maintain their functional and structural integrity.

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Insulin dysfunction is associated with cognitive deficits: in Alzheimer's disease, insulin brain concentrations are lower and insulin signaling is impaired, compared with normal brains. Also, deterioration of insulin signaling appears to be associated with ageingrelated brain degeneration such as Alzheimer's dementia and cognitive impairment in older type 2 diabetics (Zhao et al. 2004). Furthermore, insulin regulates the synthesis, secretion and break down of beta-amyloid protein, which forms into senile plaques. It has been shown that beta-amyloid protein inhibits insulin binding to insulin receptors (Gasparini et al. 2002). In fact, the symptoms of Alzheimers can be treated with insulin: intravenous infusion of insulin causes significant memory improvement in Alzheimer's disease, independent of glucose metabolism (Craft et al. 1996).

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The relevance to HPLC diets is that high-fat diets are associated with insulin resistance, as discussed before, and the misguided aim of HPLC diets is to reduce insulin secretion. (As an aside it should be remembered that insulin has an anorexic action on the brain, but only in the absence of high-fat feeding (Clegg et al. 2011)). Added to this factor is that ketosis is associated with insulin resistance, causing cell surface binding to be reduced: an experiment on adrenal cells discovered that 24 hour bathing in the ketone acetoacetate resulted in reduced insulin binding by 38% (Yokoo et al. 2003). The mechanism was found to be due to decreased insulin receptor mRNA, as early as 6 hours into the experiment, and a reduction in insulin receptor synthesis. Thus a ketotic state downregulates the density of cell surface insulin receptors and hence reduces insulin activation. The implications for HPLC diets are that any reduction in insulin concentration in the brain will result in reduced cognitive function, a mechanism enhanced by ketosis reducing insulin sensitivity via a reduction of insulin receptors in the brain. A further link between HPLC diets and Alzheimer's is that a diet high in processed meats such as bacon and ham, causes the formation of nitrosamines, which are neurotoxic. They are lipid soluble, cross the blood brain barrier and act as an alkylating agent of guanine, thus triggering DNA damage. They also generate reactive oxygen species, enhancing lipid peroxidation and activating pro-inflammatory cytokines. Administration of nitrosamines to rat pups caused significant cognitive deficits, including deterioration in motor function and spatial learning, after only 4 weeks (Tong et al. 2009). Autopsies on the rats' brains revealed severe neurodegeneration, particularly in the temporal lobes (including the hippocampus) and cerebellum: a reduction in brain weight, neuronal cell loss, lipid peroxidation, cell degeneration as indicated by ubiquitin immunoreactivity, and increased levels of amyloid-beta protein precursors and phopho-tau (many features in common with Alzheimer's disease).

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The rats all gained considerable weight, developed liver steatosis and became diabetic, as indicated by pancreatic islet hypertrophy, hyperglycaemia and hyperinsulinaemia. Indeed, much of the brain damage was mediated by a dysfunction in insulin signaling. The nitrosamines initiated an up-regulation in pro-inflammatory cytokines, leading to insulin resistance and a change in the concentration of brain insulin receptors: this caused impaired insulin binding within the brain. As mentioned before, the temporal lobe (which determines memory) and the cerebellum, are dependent on optimum insulin signaling to function fully. These nitrosamine-induced neurodegenerative changes, deficits in insulin signaling and cognitive deterioration have much in common with Alzheimer's disease. Having discussed which nutritional factors are associated with neurodegenerative conditions, are there any foods which could prevent these diseases? There is evidence that fruit and vegetable consumption protects against cognitive decline and Alzheimer's disease. A Swedish study reported that the incidence of dementia was 27% less and Alzheimer's disease 40% less in individuals consuming moderate or large amounts of fruit and vegetables in mid-life, even after controlling for age, gender, education, smoking, alcohol, BMI, total food consumption, marital status and exercise (Hughes et al. 2010). The authors concluded that the effect could be explained by the antioxidant and anti-inflammatory properties of fruit and vegetables, which offer neuroprotection by neutralising free radicals and reducing inflammation. HPLC diets limit certain vegetables and most fruit, so cannot be described as neuroprotective. In fact they are traditionally high in cholesterol (only found in animal products) and saturated fatty acids, both implicated in processes of cognitive decline, as discussed earlier. Conversely a diet low in cholesterol and saturated fat may protect against Alzheimer's disease. In terms of intellectual function, studies on vegetarian children claim that in developmental tests their mental age is over one year ahead of their chronological age, and they have higher IQs than meat-eating children of the same age. Studies on vegetarian adults also claim that they have higher IQs (both as children and adults), and are more likely to have degrees and hold down high powered jobs than non-vegetarians, even after controlling for social class (Gale et al. 2006). (People on higher incomes are more likely to be vegetarian, with the typical vegetarian most likely to be in the ABC1 economic groupings (Clery & Bailey, Food Standards Agency 2010)). There is a greater consumption of non-meat products such as bread and fruit (absent on HPLC diets) in people with higher educational attainment. The UK National Child Development Study found that at the age of 42, the vegetarians had an average childhood IQ of 109.1 compared with 100.9 for the nonvegetarians (Kanazawa 2010). It is not clear whether this is due to vegetarian diets contributing to higher intelligence, or higher intelligence increasing the likelihood of choosing a vegetarian diet, but the statistics are still of some interest in considering the optimum diet for cognitive function. HPLC diets are generally not vegetarian.

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Parkinson's disease The long-term effects of a high animal produce containing diet on mental function have been studied. For example, the American Journal of Epidemiology published research looking at the diets of over 130,000 people, which found that those who consumed the highest quintile of cow’s milk had a 70% higher risk of getting Parkinson's disease compared with those drinking the lowest quintile (Chen et al. 2007). The authors speculated that the reason for this could be that dairy products in the United States are contaminated with neurotoxic chemicals: there is substantial epidemiological and experimental evidence that exposure to pesticides may increase Parkinson’s disease risk, and postmortem studies have found relatively high levels of organochlorines, polychlorinated biphenyls, and dieldrin (present in low concentrations in dairy products) in the brains of Parkinson’s disease patients. Dairy foods also contain tetrahydroisoquinolines and precursors of b-carbolines, which are known to induce parkinsonism in rodents and primates. The implications are to aim to minimise milk and cheese consumption (at least in the USA) in order to reduce the risk of Parkinson’s disease.

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9. IRON IMBALANCE In terms of iron, there are some fears that a non-meat diet could lead to iron deficiency anaemia, as non-haem iron is absorbed less well than haem iron. (Animal tissue contains 40% haem iron and 60% non-haem iron, compared with plant foods which contain only non-haem iron). However the British Medical Association, American Dietetic Association, World Health Organisation and Physicians Committee for Responsible Medicine have stated that iron deficiency anaemia is no more common in vegetarians than meat eaters (American Dietetic Association 2003). In fact one huge UK study of 33,883 meat eaters, 18,840 vegetarians and 2,956 vegans showed that the vegans had the highest daily iron intake (Davey et al. 2003). The average values in mg per day were: meat eaters 13 mg; fish eaters 13.4 mg; vegetarians 13.4 mg and vegans 14.7 mg. Haemoglobin levels tend to be normal in non-meat eaters, especially in those whose staple food is wholemeal bread (Sanders & Reddy 1994). The proteins found in egg white and milk inhibit non-haem iron absorption (Hurrel et al. 1988), as do phytates (nuts, whole grains ) and calcium (Craig 2010). Conversely, plant foods rich in vitamin C and other organic acids substantially increase the absorption of non-haem iron, and reduce the inhibitory effects of phytates (Hallberg & Hulthen 2000). For example 75 mg of vitamin C (the amount contained in one orange) increases absorption 4-fold, and vegetarians tend to eat more fruit and vegetables (Craig 1994). Furthermore, there is evidence that long-term adaptation occurs, involving both increased absorption and decreased iron losses (Hunt & Roughead 2000). Table 9.1 lists the iron content for several different foods. Note that the top 8 sources are all plant foods, and that spinach has over 22 times more and lentils over 4 times more iron per calorie than steak. Table 9.1. Iron content of different foods: plant and animal foods compared spinach, cooked Bran Flakes collard greens, cooked Special K lentils, cooked broccoli, cooked chickpeas, cooked figs, dried

Iron mg/100 kcal 15.7 3.3 3.1 3.1 2.9 1.9 1.1 0.8

sirloin steak, broiled 0.7 chicken breast, roasted, no skin 0.6 pork chop, pan fried 0.4 flounder, baked 0.3 milk, skimmed 0.1

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Haem iron toxicity Concerns about iron deficiency anaemia can lead to overcompensation with iron supplements or excessive amounts of red meat, and the opposite problem can ensue: iron overload. Haem iron's absorption is less well controlled: unlike non-haem iron, it is absorbed whether the body needs it or not. The extreme consequences of iron overload are seen in primary haemochromatosis, a genetic condition affecting one in 250 people, resulting in excess iron storage in the tissues. The organs most affected are the heart, liver, pancreas and skin. It is associated with heart dilatation, arrhythmias, heart failure, insulin dependent diabetes, fibrosis of the liver, cirrhosis, liver failure, and liver cancer (Franchini 2006). Other associated diseases are osteoarthritis, osteoporosis, premature ageing, cancer of the colon, and early onset of neurodegenerative disorders such as Alzheimer's, Parkinson's and Huntington's disease. Iron toxicity can also occur in secondary haemochromatosis, a non-genetic condition of excess iron overload. This can result from a high haem iron diet, in people with a disordered iron regulatory system who absorb too much iron. If they consume excessive intakes of red meat, the large quantity of haem iron can overwhelm the iron storage capacity of the body, and the body has only limited ways of getting rid of it: minute quantities are lost through loss of hair, skin cells, finger nails, and in premenopausal women excess iron is lost through menstruation. A US study of 1,016 men and women over the age of 67 found that 12.9% overall and 13.9% of men had elevated iron stores (ferratin over 300 mcg/litre), compared with only 1.2% with iron deficiency anaemia (Fleming et al. 2001). In fact 28% of men were predisposed to store too much iron (ferratin over 200 mcg/litre). Medical consensus advises men and postmenopausal women not to take iron supplements unless their doctors prescribe it, in order to avoid oxidative stress and ageing of the organs. Ageing in rats and humans is associated with iron accumulation in the tissues, particularly the liver and the heart (Cook & Yu 1988; Killilea DW et al. 2004). Haem iron causes oxidative stress in the body: it acts as a catalyst for the formation of free radicals, powerful pro-oxidants which attack cellular membranes, proteins and DNA (Meneghini 1997). Excess cardiac iron has been linked to cardiac hypertrophy, dilatation and cardiac myocyte (heart muscle cell) death (Hahali et al. 2005). One experiment looking at rats, found that the iron content in aged rats' hearts was 72% higher and livers 87% higher, than young adult rats (Arvapalli et al. 2010). The aged hearts were also enlarged, with an increase in heart-to-body ratio of 48%. These changes were associated with increased measures of apoptosis (cell death) in cardiomyocytes. Giving the iron chelating agent desferasirox reduced the iron content in the ageing hearts and livers by 37% and 56% respectively, which was associated with reduced rates of apoptosis. As it has been demonstrated that apoptosis plays a key role in mediating age-associated cardiac dysfunction (Bernecker et al. 2003), reducing the iron content of the diet from the age of 50 or 60 may help in slowing down the ageing process. Another pathological consequence of high haem iron levels is that the subsequent oxidative stress can increase the likelihood of atherosclerosis (van der A et al. 2005).

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(Non-haem iron shows no association with coronary heart disease risk.) The mechanism is explained by excess haem iron forming highly reactive hydroxyl radicals, which catalyse lipid oxidation, thus increasing the formation of highly atherogenic oxidized LDL cholesterol. These hydroxyl radicals play an important role in one of the crucial steps in early atherosclerosis. The hydroxyl radicals also aggravate myocardial damage. In addition, the effect of oxidative stress on DNA results in spontaneous mutations and cancer, as discussed earlier. There is a strong correlation between haem iron intake and diabetes, independent of BMI (Rajpathak et al. 2009), whereas non-haem iron is negatively correlated (Lee et al. 2004). Haem iron promotes oxidative stress and free radicals, causing damage to pancreatic beta cells (Wolf 1993), and interferes with glucose metabolism, reducing pancreatic insulin synthesis and secretion. Lowering body iron by phlebotomy in omnivorous male volunteers to levels seen in vegetarians, results in a 40% improvement in insulin sensitivity (Hua et al. 2001). Any increased risk of diabetes from a haem iron diet is going to add to the increased of heart disease also found with a high haem iron intake. Thus an HPLC diet high in haem iron (meat, fish, poultry) will contribute to the risk of both diabetes and heart disease.

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10. PROTEIN Plant-based protein Benefits of plant-based protein The health benefits of emphasising a plant-based source of protein are neatly summed up in Table 10.1 (taken from Dr Joel Fuhrman's Cholesterol Protection for Life). Here we can see that green vegetables have more protein per 100 calories than sirloin steak, as well as numerous other vitamins and minerals, and no cholesterol. Table 10.1. Nutrients in 100 calorie portions of steak compared to different greens Protein g Calcium mg Iron mg Magnesium mg Fibre g Phytochemicals Antioxidants Folate mcg B2 mg Niacin mg Zinc mg Vitamin C mg Vitamin A IU Vitamin E IU

Sirloin steak 5.4 2.4 0.7 5 0 0 0 3 0.04 1.1 1.2 0 24 0

Broccoli 11.2 322 3.5 74.5 4.7 Very high Very high 257 0.71 2.8 1.04 350 7750 26

Romaine lettuce 7.5 374 7.7 60.5 4 Very high Very high 969 0.45 2.2 1.2 100 10,450 32

Kale 11 470 5.8 97 3.4 Very high Very high 60 0.32 2.1 0.55 329 23,407 34

Looking at a wider variety of plant and animal foods, the difference is just as striking. Table 10.2 Nutritional composition of 500 kcal of tomatoes, spinach, lima beans, peas and potatoes compared to 500 kcal of beef, pork, chicken and whole milk (equal parts) Plant-based foods Animal-based foods Cholesterol (mg) -137 Fat (g) 4 36 Protein (g) 33 34 Beta-carotene (mcg) 29,929 17 Fibre (g) 31 -Vitamin C 293 4 Folate (mcg) 1168 19 Vitamin E (mg_ATE) 11 0.5 Iron (mg) 20 2 Magnesium 548 51 Calcium (mg) 545 252

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Table 10.2 (taken from The China Study), compares the nutrient composition of 500 calories of equal parts of tomatoes, spinach, lima beans, peas and potatoes, with 500 calories of equal parts of beef, pork, chicken and whole milk. Again, the superior nutritional profile of plant-based foods over animal-based foods is highlighted: less fat, no cholesterol, an abundance of fibre, vitamins and minerals, with no loss of protein. The American Heart Association states: “... it is impossible to design an amino acid– deficient diet based on the amounts of unprocessed starches and vegetables sufficient to meet the calorie needs of humans. Furthermore, mixing foods to make a complementary amino acid composition is unnecessary... The reason it is important to correct this misinformation is that many people are afraid to follow healthful, pure vegetarian diets—they worry about 'incomplete proteins' from plant sources. A vegetarian diet based on any single one or combination of these unprocessed starches (e.g, rice, corn, potatoes, beans), with the addition of vegetables and fruits, supplies all the protein, amino acids, essential fats, minerals, and vitamins (with the exception of vitamin B12) necessary for excellent health. To wrongly suggest that people need to eat animal protein for nutrients will encourage them to add foods that are known to contribute to heart disease, diabetes, obesity, and many forms of cancer, to name just a few common problems.” (McDougall, American Heart Association 2002). It should be remembered that the body cannot store protein, so any excess is converted into carbohydrate: one might as well have eaten this “side product” carbohydrate in the first place and gained the benefits of its fibre, vitamin and mineral content. On a personal note, I recently experimented on my own diet by doing the opposite of an HPLC diet: cutting down on protein and increasing my carbohydrate content. Whilst maintaining my usual exercise level of around 40 minutes of walking or cycling a day, in 4 weeks I had actually lost 1.5 kg, yet my muscle mass was the same (using bioimpedance body composition scales which also measure muscle mass). Result: 24% fat, BMI 19.5. I ensured that I was consuming at least 60 g of protein a day, whilst enjoying bowls of porridge and muesli, wholemeal bread sandwiches, and potatoes, along with my usual generous helpings of pulses, nuts, seeds, vegetables and 4 pieces of fruit a day. I felt full throughout the day and was thus consuming lower calories overall. Whenever I attempt to cut the carbohydrate content and replace it with protein, I get the feeling that I “haven’t really eaten” and have a constant craving to eat a bit more: I end up eating much more calories of the protein food than the carbohydrate calories I am replacing, with no subsequent weight loss. This experiment has been an illuminating exercise in testing out the HPLC hypothesis in reverse, and I have had similar results in patients who were “stuck” whilst following an HPLC diet, but who then lost weight by replacing the excess protein with fibrous complex carbohydrates.

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Protein content of foods compared Is it possible to design a high-protein diet where the source is plant protein, not animal protein? All plant foods apart from sugar, honey and some fruit contain over 5% protein. Some examples of the protein content per calorie of different foods are listed in Table 10.3. Table 10.3. The percentage protein per calorie of different foods % protein per calorie banana 5 blueberries 8 kiwi fruit 9 raspberries 9 brown rice 9 clementine 10 corn on the cob 11 baked potato 13 pasta 14 fruit yogurt 15 wholemeal bread 19 cheeseburger 21 meat loaf and gravy 24 grilled bacon 24 cheese 25 lamb steak 25 grilled lamb chop 26 frozen peas 30 Quorn sausages 31 cooked lentils 36 Quorn balls 40 frozen petit pois peas 40 Fry's traditional burger 42 tofu 44 frozen broccoli 45 Fry's traditional sausage 50 Linda McCartney vegemince 50 cooked spinach 51 Linda McCartney veg burger 51 Quorn pieces 54 dried soya mince 63 Realeat chicken style pieces 85 Table 10.3 shows that the examples of animal products are less than 26% protein, while the products over 26% protein are vegetarian, and all the foods over 54% are vegan.

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Protein quality One of the main benefits of eating soya protein is that it is now considered to have a similar protein quality to animal proteins. Up until 1990 the Protein Efficiency Ratio was used to assess protein quality. This was found to be flawed, because it was based on the requirements of young rats, which need more sulphur-containing amino acids (methionine and cysteine) to make fur (Food & Agriculture Organisation/World Health Organisation 1990). Since 1990 the Protein Digestibility Corrected Amino Acid Score has been used, based on human requirements. This score is endorsed by World Health Organisation, the United States Food and Drug Administration, the United Nations University and the National Academy of Sciences. A score of 1 is a perfect score, indicating that the food contains all the essential amino acids required for human needs. Some examples of protein quality scores are listed in Table 10.4 (adapted from Hoffman & Falvo 2004). Table 10.4. Protein Digestibility Corrected Amino Acid Score of soya protein, milk, egg white, Quorn, and beef Protein Digestibility Corrected Amino Acid Score Soya protein 1.0 Milk 1.0 Egg white 1.0 Mycoprotein (Quorn) 0.99 Beef 0.92 Clearly, there are many plant foods with more protein per calorie than certain meat and dairy foods, and are of excellent quality. Healthy alternatives to animal protein (if following a low-carbohydrate diet lacking in whole grains) are pulses, including soya and low-fat soya products, nuts and seeds, and certain fake meat products (the ones which are low in fat). These are all widely available in supermarkets and health food shops, and are already part of a vegetarian's repertoire. The foods listed here contain no monosodium glutamate and are all low in fat and saturated fat. In my opinion it doesn't matter that these foods are processed, so long as the end result is low in fat/saturated fat, and they lack any harmful additives. These products are all dried, refrigerated or frozen and usually produced with health benefits in mind, so there is no need for extra additives. Table 10.5 lists some fake meats, with a favourable ratio of protein to fat and saturated fat, compared with some animal protein foods.

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Table 10.5. Fat and protein content of animal protein and vegetable protein foods Animal protein grilled bacon lamb steak cheese lamb chops grilled steak eggs roast beef roast duck breast roast chicken

Protein % per calorie 24% 25% 25% 26% 33% 34% 50% 54% 67%

Fat g per 100g (mostly sat.) 25g 31g 34g 29g 21g 11g 12g 9.7g 5.4g

Vegetable protein

Protein % Fat g per 100g per calorie (mostly unsat.) Fryâ&#x20AC;&#x2122;s traditional burgers 42% 4.4g Linda McCartney vegemince 50% 2.3g Quorn pieces 54% 2.4g Linda McCartney veg burger 51% 2.9g Quorn mince 61% 2.0g Quorn balls 49% 2.0g Real Eat chicken style pieces 85% 1.6g Nealâ&#x20AC;&#x2122;s Yard dried soya mince 63% 1.5g

Fat % per calorie (mostly sat.) 76% 75% 75% 74% 67% 66% 50% 46% 33% Fat% per calorie (mostly unsat.) 26% 24% 23% 21% 19% 18% 11% 4%

Table 10.6 lists detailed nutritional information on some vegetable protein foods. Here we can see that the vegetable protein foods on the list contain less fat than all of the animal protein foods, whilst providing more protein than most of the meat. Furthermore, the fat in the animal foods is mostly saturated, compared with the vegetable foods which have minimal saturated fat. When attempting to lose weight, it is absurd to overlook Quorn in particular, as there are dozens of different delicious varieties which have a much lower fat and saturated fat content than chicken, other meats, eggs and cheese. Quorn provides complete protein, with the benefit of fibre too. For example Quorn mince contains 75% less fat and saturated fat than lean beef mince. It also causes greater satiety than equivalent amounts of chicken (discussed earlier). Quorn is occasionally criticized for having the potential to cause side effects. However, all protein foods have the potential to cause an adverse reaction, and with Quorn this is rare. It is possible that some people who are allergic to fungi may also react to Quorn. Approximately only 1/140 000 consumers report adverse reactions after eating Quorn (Katona & Kaminski 2002).

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Table 10.6. Nutritional composition of various fake meats (all available in Holland & Barrett, and Quorn in any supermarket) All figures per 100 g (% is the percentage per calorie) Real Eat chicken style pieces (vegan) (soya) kcal 136 protein 29g (85%) carb 1.5g fat 1.6g (11%) sat. fat 0.5g (3%) fibre 4.4g

Linda McCartney vegemince (vegan) (includes textured soya protein) kcal 107 protein 13.5g (50%) carb 7g fat 2.8g ( 24%) sat. fat 0.25g ( 2%) fibre 4.3g

Neals Yard dried soya mince (vegan) (includes defatted soya flour) kcal 330 (dried so small portions) protein 52g (63%) carb 34g fat 1.5g ( 4%) sat. fat 0.2g ( 0.5%) fibre 15g

Quorn mince (includes mycoprotein & egg white) kcal 94 protein 14.5g (61%) carb 4.5.g fat 2g (19%) sat. fat 0.5g (4.8%) fibre 5.5g

Quorn pieces (includes mycoprotein & egg white) kcal 103 protein 14g (54%) carb 5.8g fat 2.4g (23%) sat. fat 0.6g (5%) fibre 5.5g

Linda McCartney vegetarian burgers (incl. soya protein concentrate & egg white) kcal 124 protein 15.8g (51%) carb 12.2g fat 2.9g (21%) sat. fat 1g ( 7%) fibre 5.8g

Fryâ&#x20AC;&#x2122;s traditional burgers (vegan) (incl. wheat & soya protein) kcal 149 protein 15.8 (42%) carb 10.7 fat 4.4 (26%) sat. fat 2.2 (13%)

Quorn balls (incl. mycoprotein & egg white) kcal 110 protein 11g (40%) carb 12g fat 2.2g (18%) sat. fat 1g ( 8%) fibre 4.5g

Fish On the topic of fish, I would like to draw attention to the Committee on Toxicity of Chemicals in Food, Consumer Products and the Environment (COT) which published a detailed report advising limits on fish consumption because of the high levels of

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pollutants such as mercury, dioxins, and dioxin-like polychlorinated biphenyls (PCBs; COT 2004). Mercury is found in particularly high concentrations in carnivorous fish such as shark, swordfish and marlin. The COT advise no more than one weekly portion of 140 g of these fish, and none to be consumed by children, pregnant women, and women intending to get pregnant. The organic form of mercury, methylmercury, has a half life of 70 days, and is associated with toxic effects on the kidneys and central nervous system. In pregnancy, mercury exposure has been known to cause cerebral palsy and mental retardation. Tuna has a considerable amount of mercury in it too, so pregnant women and women intending to get pregnant are advised to consume no more than 140 g of fresh tuna, or two 140 g tins of canned tuna a week. Analysis of tuna samples found that 8.9% of tuna cans and 20% of fresh tuna exceeded the standard for mercury (Storelli et al. 2010). Mercury is also found in higher amounts in shellfish. Dioxins and dioxin-like PCBs are lipophilic contaminants, which are so highly toxic that their production was internationally banned in 2001. However pollution of the environment still exists, and as the half life is 10 to 15 years this affects the food chain: PCBs are present in higher concentrations in oily fish, meat such as hamburgers and poultry, eggs and dairy products. Once ingested, PCBs are stored in adipose tissue, and levels reflect a lifetime of exposure. An extensive review of their sources and metabolic effects is summarized here (Crinnion 2011). Toxic effects include cancer (particularly lung and liver cancer); type 2 diabetes; reduced immunity (e.g. increased apoptosis of white blood cells); hypothyroidism (e.g. reduced levels of T3, T4 and thyroid transport proteins and increased levels of antithyroid antibodies); detrimental effects on reproductive systems (e.g. endometriosis, increased miscarriage and decreased sperm production and motility); and neurological toxicity (e.g. cognitive defects). One study found that anglers in the Great Lakes consuming at least 11 kg annually of their catch had high plasma levels of PCBs, compared with non-fish eaters; the higher the PCB levels, the more memory and learning problems were experienced. Exposure to the foetus in utero is particularly hazardous as studies reveal that maternal consumption (e.g. fish) leads to detrimental mental and motor development in the offspring, including reduced intellectual functioning, increased cognitive defects, lowered IQ scores and increases in hyperactivity. There is also weaker evidence that PCBs cause cardiovascular disease. The Crinnion review states that particularly high levels of PCBs are present in Atlantic farmed salmon, tinned sardines, hamburgers and butter, and concludes that these foods should be avoided. Even small amounts of contaminated foods are dangerous: it quotes a study where only 2 fish meals a month resulted in hypothyroidism. The COT reports that herring has particularly large amounts, followed by salmon, mackerel and trout. Certain brands of fish oil supplements contain even higher levels. The Tolerable Daily Intake (TDI) has been introduced to safeguard from overexposure. For example a 140 g portion of herring, kipper or eels by a 60 kg adult, would result in exceeding the TDI by 44-78%. 2 portions of salmon would result in exceeding the TDI by 40%, and 3 portions of trout would also exceed the TDI. The COT has concluded that no more than 2 weekly portions of oily fish should be consumed.

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Other hazardous contaminants found in fish are arsenic, cadmium, lead, and brominated flame retardants (BFRs). The COT report states that the main sources of arsenic in the diet are fish, followed by poultry. Consumption is associated with cardiovascular disease, peripheral vascular disease, diabetes and reproductive disorders. Cadmium is found particularly in shellfish and is associated with kidney, lung and bone damage. Lead is associated with brain damage, paralysis, anaemia, gastrointestinal symptoms and damage to the kidneys, reproductive, immune and nervous system. It is found in various different species of fish, which has led to the European Commission to regulate the limit of these particular species. BFRs (which can cause neurodevelopmental disorders) are found in particular species of fish inhabiting the North Sea, and UK rivers. Anglers eating their own catches of trout and eels may be at risk. HPLC diets often state that fish may be eaten freely, which does not take into account the maximum limits as discussed above. Furthermore, oily fish contains 17% to 25% saturated fat (Food Standards Agency 2002). Omega 3 fats can be obtained from flaxseed, walnut and rapeseed oil, or pure EPA/DHA capsules can be taken, which are derived from algae, with no risk of contamination or damage to the vastly depleted fish stocks. (It takes 10 kg of fish bodies to produce 1kg of fish oil.) I use the brands of "VPure" and “Opti-3” capsules, which contain a much higher dose of DHA (necessary for the brain) than fish oil capsules, and are easily bought on-line for around £10 for a month's supply. The recommended is dose is two Opti-3 capsules, which provides the body with 200mg of EPA, and 400mg of DHA. Soya Phytoestrogens Soya has received some criticism, regarding its oestrogen-like effects. However it seems that this criticism is unfounded. The Food Standards Agency's Committee on Toxicity (COT) published an extensive review on the health implications of phytoestogens (COT 2003). They found that there was no evidence that people who regularly eat high quantities of soya, such as the Chinese and Japanese, have altered sexual development or impaired fertility. Indeed, a supposed lack of male reproductive capacity does not appear to have been a problem in China, the most populated country in the world! A meta-analysis of research found that there was no effect of soya on testosterone or dihydrotestosterone levels (the biologically active metabolite of testosterone) (HamiltonReeves et al. 2010). Similarly, evidence shows that soya does not increase oestrogen levels, even at intakes as high as 150 mg/day (Messina 2010). Detrimental effects of soya on semen and sperm quality are also not seen in clinical data (Beaton et al. 2010). Many other studies have looked at infants fed on soya-based formulas and have found no evidence of hormonal effects once adulthood is reached. One study looked at over 30 different outcomes including height, weight, and effects on puberty and fertility (Strom et al. 2001). The differences between the soya formula-fed and the cows’ milk formula-fed

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groups were not statistically significant: no evidence of problems with sexual development or general health was found. There are approximately 4 mg of isoflavones in each gram of soya protein (Messina & Redmond 2006). The intake of isoflavones varies widely: it has been measured as high as 18-200 mg a day in China and Japan (COT 2003), with a quarter of Japanese consuming around 78.5 mg/day (equivalent to 20 g soya protein/day) (Ahkter et al. 2008). In the UK, the level of isoflavone intake is just 1.2 mg for UK omnivores, and 7.4 mg a day for UK vegetarians (Ritchie et al. 2006). Even the highest levels recorded in the UK (breastfeeding vegan mothers) have an average intake of 75 mg isoflavones a day, well within the levels seen in Asia, and with no ill effect. Objections to soya quote studies which are based on animal models, which are redundant when examining soya because the doses used are 6- to 20-fold greater than human exposure (Messina et al. 2006), the route of administration is often subcutaneous which bypasses gastric and hepatic metabolism, and raw soya is used. No-one eats raw soya! Furthermore mice, rats and monkeys all metabolise soya isoflavones differently from humans, resulting in markedly higher circulating levels of the biologically active forms. (Setchel 2006). The Food Standards Agencyâ&#x20AC;&#x2122;s Committee on Toxicity has done extensive reviews of phytoestrogens and soya-based infant formula, and states that where parents have been advised by their doctor to feed their baby soya-based formula, they should continue to do so. "The Working Group considered that the findings from these studies do not provide definitive evidence that phytoestrogens present in soya-based infant formula can adversely affect the health of infants." (COT 2003). Soya and cancer The argument that "phytoestrogens cause cancer" makes no sense when considering the fact that although they are chemically and structurally similar to the mammalian oestrogen, oestradiol, their oestrogenic activity is between 1,000 and 10,000 times weaker than that of oestradiol (Messina et al. 2006). Isoflavones have much less binding affinity to the oestrogen receptor and are thus more likely to block the receptor than act as an agonist of the receptor. This means that they are classified as selective oestrogen receptor modulators (SERMS), just like the anti-oestrogen breast cancer drug tamoxifen i.e. they are mixed oestrogen agonists/antagonists (Oseni et al. 2008). Thus phytoestrogens have oestrogen like effects in some tissues, but have anti-oestrogenic effects in other tissues where oestrogen receptors are present (Pinkerton & Goldstein 2010). In contrast, the mammalian eostrogen oestrodiol has a 100% binding affinity with oestrogen receptors and will therefore stimulate them. Most vegetables naturally contain phytoestrogens or substances that are converted to phytoestrogens in the gut. Phytoestrogens are found in the roots, stems, seeds or flowers of plants, acting as part of the plant's defence mechanism against fungi and other microorganisms. These foods include strawberries, cranberries, grapes, apples, yams, sweet potatoes, cabbage, whole grain cereals, seeds, spices, tea, hops, peas, beans and lentils: all widely accepted as health-promoting foods. The main source of oestrogens in

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the human diet is actually dairy products, as over 66% of commercial milk is taken from pregnant cows (Danby 2005): 60-80% of dietary oestrogens are from dairy products with the remaining 20-40% deriving from meat products (Hartmann et al. 1998). This mammalian oestrogen is far more powerful than phytoestrogens and it is this, therefore, that has the potential to cause detrimental hormonal disruption. Soya foods have been studied for many years in relation to their ability to reduce the risk of breast, prostate, endometrial and colon cancer. For example in 2009, The Shanghai Breast Cancer Survival Study on over 5,000 women diagnosed with breast cancer, found that those who ate at least 11 g of soya protein a day were less likely to die from the disease and had a significantly lower risk of recurrence (Shu et al. 2009). The China Study highlighted the fact that in rural China, where the incidence of breast cancer is only one in 10,000 women, the main source of protein is vegetables rich in phytoestrogens such as soya (Campbell & Campbell 2006). Other epidemiological studies indicate that eating soya foods in childhood and adolescence reduces the risk of breast cancer, and that the risk continues to fall if consumed as adults. The reductions in risk range from 28 to 60% (Messina & Messina 2010). The 60% reduction in risk was found in children who consumed soya at least 6 times a month (Korde et al. 2009). Cancer Research UK has highlighted a very important study showing that women who eat large amounts of soya are 60% less likely to have the "dense" tissue associated with breast cancer than those who ate the least (highest quartile of intake versus lowest quartile) (Jakes et al. 2002). Furthermore, epidemiological evidence demonstrates that consumption of soya post-diagnosis improves prognosis as measured by tumour recurrence and mortality (Shu et al. 2009; Guha et al. 2009). Numerous studies have reported that soya products reduce breast cancer in laboratory experiments, while milk and the growth factors and hormones it contains have been shown in many different experiments to promote the growth of breast and prostate cancer cells. For example, tumours are initiated and proliferate with 20% casein diets, but not with 20% soya protein diets (Campbell & Campbell 2006). What is the mechanism for the protective effect of soya and other legumes on hormonedependent cancers? There are several different anti-carcinogenic phytochemicals with different mechanisms of action. These include phytoestrogens, antioxidants, phytate, protease inhibitors, and polypeptides. (Chick peas and lentils also contain antioxidants, protease inhibitors and the complete range of isoflavones.) Soya has a high content of phytoestrogens such as genistein and daidzein, which act through a number of different mechanisms to prevent breast cancer and metastases (the spread of cancer cells) (Chambers 2009; Banerjee et al 2008): 1. Isoflavones antagonize oestrogen and androgen-mediated signaling pathways in the process of carcinogenesis: they have a similar action to the anti-breast cancer drug tamoxifen.

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2. Genistein is a potent inhibitor of angiogenesis, the growth of new blood supply systems that cancer cells need to grow. 3. Genistein inhibits the activation of inflammatory signaling pathways involved in carcinogenesis, thus inhibiting the proliferation of breast cancer cells. 4. Genistein inhibits metastasis (the spread of cancer cells): it appears to influence the interaction of metastatic cancer cells within the breast. 5. Isoflavones and other components of legumes act as powerful antioxidants, removing the oxygen radicals involved in cancer powerful antioxidant properties. In fact genistein is now considered to be a promising agent for cancer chemoprevention (Banerjee et al. 2008). Phytate (inositol hexaphosphate) inhibits cell proliferation, cell cycle progression, metastasis, invasion, angiogenesis and also induces apoptosis (the death of cells) in cancer cells (Kolappaswamy et al. 2009). Protease inhibitors inhibit cell proliferation, the transformation of normal cells into cancerous ones, and the expression of certain genes and cellular processes that promote cancer. They also induce apoptosis in cancer cells. Polypeptides such as lunasin (also found in barley) arrest mitosis and induce apoptosis. (One mechanism of action is by reducing levels of the pro-inflammatory cytokine Interleukin-6.) There is a known cancer preventing agent derived from soya called â&#x20AC;&#x153;Bowman Birk Inhibitor Concentrateâ&#x20AC;?, which is now in human trials. This contains protease inhibitor and the polypeptide lunasin. The protease inhibitor makes the cancer preventive peptide bioavailable (Hsieh et al. 2010). Several studies have shown that a component of soya lecithin reduces the formation of acrylamide, a potent neurotoxin and cancer-inducing substance, found in carbohydrate and the amino acid asparagine containing foods which have been baked, grilled or fried to over 120 degrees centigrade, such as chips, crisps, crackers, biscuits, and toasted breakfast cereals. The mechanism is unclear, but one study, which found that ingested dark soya sauce stopped neurotoxic damage in rats primed with acrylamide, proposed that it was soya's powerful antioxidant action which partly explained its protective effect (Xichun & Minâ&#x20AC;&#x2122;ai 2009; Shuming et al. 2009). The former study found that dark soya sauce improved axonal degeneration and brain weights. The latter study also found that acrylamide-induced reductions in serotonin and thyroid hormones were improved by the administration of dark soya sauce. Epidemiological research also documents protective effects of soya on cancer. For example, with endometrial cancer, studies found that those who ate the most soya were 33% less likely to get the disease (Xu et al. 2004). In a meta-analysis of 15 epidemiological studies, soya foods reduced the risk of prostate cancer by up to 30% (only non-fermented foods such as tofu and soya milk had a protective effect) (Yan & Spitznagel 2009). Another meta-analysis of observational studies reported similar findings (Hwang et al. 2009).

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Examining this association in more detail, low-fat vegan diets containing soya have been used to lower prostatic specific antigen (PSA), a prostate cancer marker, by as much as 10%. Dr Dean Ornishâ&#x20AC;&#x2122;s team followed men diagnosed with early prostate cancer who had been randomly assigned to either a conventional no-change-in-diet group or a 10% fat vegan diet group (the Ornish Diet) (Ornish et al. 2005). At the end of one year, the PSA levels had risen by 6% in the conventional diet group, and had reduced by 4% in the low-fat vegan diet group (resulting in an overall difference of 10% between the groups). Furthermore, cell cultures taken from the blood of the vegan diet group inhibited the growth of prostate cancer cells by 70%, compared with only 9% in the conventional diet group. At follow-up after two years, 27% of the conventional diet group had needed treatment for prostate cancer, compared with only 5% of the vegan diet group (no men from the latter group had a PSA level of over 10ng/ml, compared with 16% of the treated conventional group) (Frattaroli et al. 2008). Soya isoflavones also significantly slow the rise in PSA levels in prostate cancer patients (Pendleton et al. 2008; Kwan et al. 2010). Colon cancer is another cancer which responds well to soya in the diet: colon cancer was found to be lowered in risk by eating soya foods, especially in women (Yan et al. 2010). The American Cancer Society (ACS) has made the following statement on soya products: â&#x20AC;&#x153;Can soy-based foods reduce cancer risk? As with other beans or legumes, soy and foods derived from soy are an excellent source of protein and a good alternative to meat. Soy contains several phytochemicals, including isoflavones, which have weak estrogenlike activity and may help protect against hormone-dependent cancers. There is growing evidence that eating traditional soy foods such as tofu may lower the risk of cancers of the breast, prostate, or endometrium (lining of the uterus), and there is some evidence it may lower the risk of certain other cancers.â&#x20AC;? (ACS 2011). Soya and mental function Soya foods improve cognitive ability in all age groups. For example, the Centre for Neuroscience at King's College London investigated the effects of a high soya diet (100 mg of isoflavones a day) compared with a low soya diet (0.5 mg a day). After 10 weeks the volunteers eating the high soya diet showed significant improvements in shortterm and long-term memory and mental flexibility (File et al. 2001). Further research found beneficial effects of soya on cognitive ability after only 6 weeks (File et al. 2005). Soya also helps to prevent Alzheimer's disease, by degrading the amyloid plaques associated with the disease (Hsu et al. 2009). One unfounded criticism of soya is that it "contains no cholesterol, essential for the development of the brain and nervous system" (Briffa 2010). The body makes all the cholesterol that it needs, and in fact soya is a rich source of lecithin, necessary for healthy brain development: it is essential in providing the choline component of cell membranes in every cell in the body. It has many health benefits, including improving brain function and memory, and is found in abundance in the brain and nervous system. Other health

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benefits of lecithin include helping to prevent heart disease, supporting liver function, reducing the toxicity of acrylamide, and aiding the body in removing cholesterol. Soya is also a rich source of the essential amino acid tryptophan, which is needed for the manufacture of serotonin. This neurotransmitter is essential for good mood, and it also helps regulate appetite and sleep patterns. For example a cup of edemame beans contains 116% of our daily requirements of tryptophan, and a 100g portion of tofu provides 44% (Gellateley 2010). At 0.59 g/100 g, soya provides more than double the amount of tryptophan than turkey (0.24 g/100 g). Soya and thyroid function In terms of thyroid function, there is no evidence that soya goitrogens, which can interfere with the uptake of iodine into the thyroid gland, affect thyroid function, so long as the dietary intake of iodine is adequate (Messina & Redmond 2006; Ryan-Borchers et al. 2008; Bitto et al. 2010). The International Council for the Control of Iodine Deficiency Disorders has set the RDAs for iodine as follows: 90 mcg for children aged one to three, 120 mcg for children aged 9 to 13, and 150 mcg for the ages of 14 and upwards (Food and Nutrition Board 2001). Good sources are sea vegetables, whole wheat and rye (although the iodine level may vary in the latter two due to soil quality), or if a consistent result is preferred, a kelp tablet can be taken every day. Patients with hypothyroidism are advised to take thyroxine medication on an empty stomach to enhance absorption. Soya and digestion Critics of soya point out that soya beans contain substances that can impair digestion. It is true that soya beans contain trypsin inhibitors, which impair the ability to digest protein. However the American Institute of Nutrition makes clear that trypsin inhibitors are "subject to denaturation and inactivation by heat". Furthermore, soya beans are cooked before consumption, and before making soya products such as tofu, miso, tempeh and soya milk. The United States Department of Agriculture (USDA) found soya bean foods, including soya infant formula to be "generally low in trypsin inhibitor". In any case, the USDA also states that trypsin inhibitors in soya beans are thought to help to prevent cancer (Anderson et al. 1995). Another objection to soya is the presence of phytic acid, which can bind to minerals such as iron, zinc, calcium, and magnesium, and therefore reduce their absorption. However, it is apparent that people living on high phytate diets for long periods of time become adapted, and can absorb enough zinc and other minerals to maintain an adequate status. The American Dietetic Association comments: "Calcium absorption appears to be inhibited by such plant constituents as phytic acid, oxalic acid and fibre, but this effect may not be significant. Calcium deficiency in vegetarians is rare." (Havala &Dwyer 1988).

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Calcium bioavailability from soya is surprisingly good (Fredlund et al. 2006). Furthermore, soya milks fortified with calcium provide the same amount of bioavialable calcium as cowâ&#x20AC;&#x2122;s milk, particularly if calcium carbonate is used (as in Alpro soya milk) (Zhao et al. 2005). Iron absorption from soya beans has been hugely underestimated. In fact iron absorption from soya is excellent, due to most of the iron from soya being in the form of ferratin. This type of iron is highly bioavailable, almost equal to the iron absorption of ferrous sulphate (Murray-Kolb et al. 2003). In the case of zinc, although soya protein and phytic acid inhibit its absorption, the effects are quite modest. Studies show that zinc absorption from soya is similar to or only slightly lower than from animal foods (Messina & Messina 2010). In any case, recent research has shown that phytic acid actually has many health benefits. The dietary mineral chelating effect is useful in older individuals who are subject to suffering from overmineralisation of joints, blood vessels and other parts of the body. According to the Department of Medical and Research Technology, University of Maryland School of Medicine, Baltimore, USA "Phytic acid reduces the risk of kidney stone formation and heart disease and can act as an anti-cancer agent. Phytic acid works by reducing cell proliferation and increasing the differentiation of cancer cells... Recent studies show that phytic acid, even when dosed at normal levels, does not cause deficiencies or toxic effects."(Vucenik & Shamsuddin 2003). If lowered intake of phytic acid is still desired, fermented soya products such as tempeh, miso and soya sauce have quantities half that of soya beans. Soya has favourable characteristics in terms of digestion, as it acts as an important prebiotic for beneficial probiotic bacteria, thus facilitating the many essential functions of intestinal microflora, which I outlined earlier. Prebiotics also have anti-cancer and cholesterol-lowering properties, and increase the availability of calcium, magnesium, zinc and iron for the host. Soya and aluminium If there are concerns with soya protein isolate and aluminium, one needs to bear in mind that aluminium is the earth's most abundant metal, and is naturally found in drinking water and all animal and plant foods. Soya protein isolate is considered safe enough to be put into soya-based infant formulas, which have been used for the last 3 decades in millions of babies, all growing and developing normally. In the USA, 20-25% of all formula fed babies use soya (USDA 2004). The aluminium intake of infants using soya formula is only about 25% of the upper level, established by the Food and Agriculture Organisation (Fernandez-Lorenzo et al. 1999): levels of aluminium are considered safe, and well within the upper tolerable level. The British National Formulary lists 5 different soya-based formulas, designed to be used as the sole source of nutrition in infants, or as a milk substitute in pre-school children. Any risk remains therefore theoretical. (Aluminium levels in cows' milk formula are 5 times higher than breast milk).

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Furthermore, the body absorbs very little aluminium, and that which is absorbed is excreted by the kidney. In fact soya protein isolate is used without concern in breakfast cereals, soups, sauces, baked foods, ice cream, yogurt, dairy-free products, processed meat, poultry and fish products, protein bars and weight loss shakes. If there is still a reluctance to eat soya protein isolate (for example if there is impaired renal function), then soya milk, soya yogurt, tofu, tempeh and soya mince (made from defatted soya flour) can all be used. Soya and cardiovascular disease One of the main advantages of soya is in reducing the risk of cardiovascular disease, by lowering cholesterol, reducing blood pressure, helping to prevent type 2 diabetes, and helping to improve endothelial dysfunction. I find it astonishing that anti-soya campaigners say that there is no evidence that lowering cholesterol with soya protein reduces the risk of heart disease, when in fact there is overwhelming evidence. NICE states "In high income countries cholesterol levels in excess of 3.8 mmol/litre are responsible for more than 50% of cardiovascular disease events. Blood cholesterol can be lowered by dietary change."(NICE 2008). In 2006, the American Heart Association in its review of soya, published in Circulation, stated "Soya products such as tofu, soya butter, soya nuts or some soya burgers should be beneficial to cardiovascular health because of their high content of polyunsaturated fats, fibre, vitamins and minerals and low content of saturated fat. Using these and other soya foods to replace foods high in animal protein that contain saturated fat and cholesterol may confer benefits to cardiovascular health." (Sacks et al., American Heart Association 2006). By substituting soya foods high in polyunsaturated fat for foods high in saturated fat, both cholesterol levels and coronary heart disease risk are reduced (Mozaffarian et al. 2010). Not only is there a clear fatty acid advantage as stated above, but soya also directly lowers blood cholesterol. It is possible to lower cholesterol at levels of less than the standard quoted 25 g/day soya protein. For example in the EPIC Oxford study, women consuming 6 g or more of soya protein a day had a 12.4% lower mean LDL cholesterol concentration (Rossel 2004). Other studies have found significant reductions at only 15 g/day soya protein (Harland & Haffner 2008). In addition to lowering cholesterol, soya helps to prevent cardiovascular disease by other mechanisms: reducing blood pressure and the risk of type 2 diabetes. One Scottish study found that diets containing at least 20 g of soya protein a day for 5 weeks lowered both cholesterol and blood pressure (Sagara et al. 2004). Another study reported that daidzeinrich isoflavones reduced systolic blood pressure by 15 points, (measured after 8 weeks), in hypertensive adults. The authors also discovered that systolic blood pressure reduced by 18 points in mice after only 10 days of a feed containing daidzein (Furumoto et al. 2010). Another finding was a marked reduction in abdominal adipose tissue's tumour necrosis factor alpha (TNF-alpha), which is a key component of insulin resistance in metabolic syndrome.

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A Japanese study looked at the effects of fermented soya (natto) on glucose control in men eating a traditional high GI breakfast of white rice. When natto was eaten with the rice, both glucose and insulin blood levels were lower (Tanuguchi et al. 2010). Another study on middle-aged Chinese women found that a high intake of legumes (soya beans in particular) was associated with a reduced risk of type 2 diabetes (Villegas et al. 2008). Finally, soya isoflavones are consistently effective in improving impaired endothelial function (Li et al. 2010). Thus even for individuals whose cholesterol levels are low, including soya foods in the diet could reduce coronary heart disease risk. Soya and bone density Many studies now suggest that soya protein may help increase bone density and so reduce the risk of osteoporosis: risk of fractures is reduced by a third when women consume at least 2.7 g of soya protein a day compared with those who consume less (Koh et al. 2009). This could be due to the lower sulphur amino acid content of soya protein, resulting in less dissolution of bone to neutralize body acid, and hence calcium retention (WHO 2007). It could also be due to the oestrogen-like effect of isoflavones which exert skeletal benefits: loss of oestrogen is a major cause of osteoporosis in postmenopausal women. For example one study found that in postmenopausal osteopenic women, after 3 years the group given 54 mg/day of genistein (equivalent to 4 servings of soya foods) gained 9% spinal bone density compared with the placebo group who lost 11% (Marini et al. 2008). These results agree with another study which after only 12 weeks reported that isoflavone supplementation increased bone mineral density in the spine and femoral neck in a dose-dependent fashion (Ye et al. 2006). Soya's nutritional quality Any argument that soya protein is of "inferior" quality is quashed by the fact that all eight essential amino acids are present: sulphur containing amino acids are included, but in lower amounts than the non-sulphur ones. It should be remembered that the updated and internationally recognised Protein Digestibility Corrected Amino Acid Score is based on human requirements, not rats' requirements (to make fur), so there is less demand for the sulphur containing amino acids. Soya concentrate has a score of 0.99, compared with beef with 0.92. Furthermore, soya protein contains a higher percentage of the â&#x20AC;&#x153;critical clusterâ&#x20AC;? of amino acids needed for muscle synthesis (arginine, glutamine, leucine, isoleucine and valine) than beef, milk or egg protein (Manninen 2002). Soya milk contains practically no carbohydrate for the same number of calories as skimmed milk, as seen in Table 10.7. Furthermore, the GI of soya milk is only 36, compared with cow's milk which has a GI of 42, and soya milk is a lot less insulinogenic than cow's milk, which has an extremely high insulin index score of 142, as discussed earlier. Thus if an HPLC approach is desired, it is preferable to replace cowâ&#x20AC;&#x2122;s milk with soya milk.

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Table 10.7. Carbohydrate content of soya milk, skimmed milk, soya yogurt and cow's yogurt Soya milk Skimmed milk Soya yogurt Low-fat yogurt

g carbohydrate per 100g 0.2 4.5 (all in the form of sugars) 2.8 7.8 (all in the form of sugars)

Any potential arguments against soya and some myths surrounding it are adequately debunked in The Soya Story (Gellatley et al. 2010). To summarise, soya is an excellent source of calcium, magnesium, zinc, vitamin B3, vitamin B6 and vitamin B9 (folate), and all eight essential amino acids. Soya foods protect hearth health by lowering cholesterol and blood pressure. In addition they help prevent diabetes, menopausal symptoms and certain cancers such as breast cancer. They can also boost bone health, memory and mental flexibility.

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11. WORLD HEALTH ADVISORY BODIES’ STATEMENTS ON HPLC DIETS Numerous international organisations have cautioned against the use of HPLC diets. There are many different reasons for this, as outlined previously. A review paper of HPLC diets included some of these by saying “low carbohydrate diets may result in: abnormal metabolism of insulin; salt and water depletion that may cause postural hypotension, fatigue, constipation, and nephrolithiasis; excessive consumption of animal proteins and fats that may promote hyperlipidaemia, and higher dietary protein loads that may impair renal and bone function” (Frigolet et al. 2011). It goes on to state that HPLC diets impair insulin action in the hippocampus, prevent vascular regeneration in blood vessels, and cause triglyceride accumulation in the liver. They should not be used in patients with gastrointestinal, bone, renal, cardiovascular, or acid/base abnormalities, and only with monitoring of kidney and liver function by health professionals, and only in the short term. The review then points out that even prescribing an HPLC diet in the short-term is not helpful: advising a patient to follow a diet for only a couple of months, and then to change food habits later is confusing. Patients really need to be advised to eat low glycaemic index food, plant-based protein, plenty of fibre, with limited sugar, sodium and saturated fat intake for long term weight loss and health. The following organisations have published statements on HPLC diets: 1. Association for the Study of Obesity (ASO) The ASO's message on HPLC diets is that most of the weight loss is due to glycogen and water. At one year there is no difference in weight loss between HPLC dieters and lowfat dieters on 1200-1800 calories a day. There is nothing “magic” about an HPLC diet: it is just a way of reducing calories, and this is why HPLC dieters lose weight. ASO confirms the side effects of increased rates of kidney stones, excess calcium loss, increased osteoporosis, raised uric acid levels leading to gout, and the high saturated fat content leading to cardiovascular disease and bowel cancer. I quote from an ASO course regarding the HPLC method: “there is no evidence to recommend it.” (Association for the Study of Obesity 2004). 2. American Heart Association (AHA) The American Heart Association has published a statement on high-protein diets on its website, intended for the general public: Most of these diets aren't balanced in terms of the essential nutrients our bodies need. Some are high protein and emphasize foods like meat, eggs and cheese, which are rich in protein and saturated fat. Some restrict important carbohydrates such as cereals, grains, fruits, vegetables and low-fat dairy products. If followed for a long time, they can result in potential health problems… These diets can cause a quick drop in weight because eliminating carbohydrates causes a loss of body fluids. Lowering carbohydrate intake also prevents the body from completely burning fat. In the diets that are also high in protein, substances called ketones

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are formed and released into the bloodstream, a condition called ketosis…. ….Most Americans already eat more protein than their bodies need. And eating too much protein can increase health risks. High-protein animal foods are usually also high in saturated fat. Eating large amounts of high-fat foods for a sustained period raises the risk of coronary heart disease, diabetes, stroke and several types of cancer. People who can't use excess protein effectively may be at higher risk of kidney and liver disorders, and osteoporosis. That's why the American Heart Association guidelines urge adults who are trying to lose weight and keep it off to eat no more than 35 percent of total daily calories from fat and less than 7 percent of total daily calories from saturated fat and less than 1 percent of total daily calories from trans fat. On most high-protein diets, meeting these goals isn't possible. Some high-protein diets de-emphasize high-carbohydrate, high-fiber plant foods. These foods help lower cholesterol when eaten as part of a nutritionally balanced diet. Reducing consumption of these foods usually means other, higher-fat foods are eaten instead. This raises cholesterol levels even more and increases cardiovascular risk. High-protein diets don't provide some essential vitamins, minerals, fiber and other nutritional elements. A high-carbohydrate diet that includes fruits, vegetables, nonfat dairy products and whole grains also has been shown to reduce blood pressure. Thus, limiting these foods may raise blood pressure by reducing the intake of calcium, potassium and magnesium while simultaneously increasing sodium intake. What's the best way to lose weight? A healthy diet that includes a variety of foods and is rich in fresh fruits and vegetables along with regular physical activity… By paying attention to portion size and calories and following our guidelines, you can enjoy healthy, nutritionally balanced weight loss… (American Heart Association 2012). The AHA has also published a more detailed statement for healthcare professionals on HPLC diets in Circulation. This provides an excellent summary of the subject of HPLC diets. I quote extensively here: “Dietary Protein and Weight Reduction: A Statement for Healthcare Professionals From the Nutrition Committee of the Council on Nutrition, Physical Activity and Metabolism of the American Heart Association Abstract—High-protein diets… They also often promote misconceptions about carbohydrates, insulin resistance, ketosis, and fat burning as mechanisms of action for weight loss…. These diets are generally associated with higher intakes of total fat, saturated fat, and cholesterol because the protein is provided mainly by animal sources. In high-protein diets, weight loss is initially high due to fluid loss related to reduced

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carbohydrate intake... Beneficial effects on blood lipids and insulin resistance are due to the weight loss, not to the change in caloric composition… High-protein diets are not recommended because they restrict healthful foods that provide essential nutrients and do not provide the variety of foods needed to adequately meet nutritional needs. Individuals who follow these diets are therefore at risk for compromised vitamin and mineral intake, as well as potential cardiac, renal, bone, and liver abnormalities overall. Role of Protein in the Diet ...Protein intake above the required amount is inefficiently used by the body and imposes additional burdens of metabolizing and excreting excess waste products (e.g. urea and ammonia) by the liver and kidney…. High-Protein Diets and Weight Reduction … Initial weight loss, however, may be attributed in part to the diuretic effect from lowcarbohydrate intake and its effects on sodium and water loss, glycogen depletion, and ketosis…strict eating schedules, and limited tolerance of high-protein foods reduce overall flexibility and offer initial appeal. These characteristics may help limit caloric intake and may account for weight loss. However, neither the efficacy of these diets compared with higher carbohydrate diets in promoting weight loss nor the safety of these diets has been documented in long-term studies. The amount of protein recommended in high-protein diet regimes exceeds established requirement and may impose significant health risks. First, animal protein (rather than plant-based proteins that also contain carbohydrates) is generally advocated in these diets. A diet rich in animal protein, saturated fat, and cholesterol raises low-density lipoprotein (LDL) cholesterol levels, an effect that is compounded when highcarbohydrate, high-fibre plant foods that help lower cholesterol are limited or eliminated. Furthermore, a high-carbohydrate diet that includes fruit, vegetables and nonfat dairy products, and whole grains has been shown to lower blood pressure, so limitation of these foods may raise blood pressure via associated reductions in potassium, calcium, and magnesium, coupled with increasing sodium intake. High protein foods such as meat, poultry, seafood, eggs, seeds, and nuts are high in purines. Purines are broken down into uric acid, so excess consumption of these foods increases uric acid levels and may cause gout in susceptible individuals. A surplus of protein in the system also increases urinary calcium loss, which may facilitate osteoporosis. In addition, elimination or severe restriction of fruit, vegetables, beans, and whole grains from the diet may increase cancer risk. A very-high-protein diet is especially risky for patients with diabetes, because it can speed the progression, even for short lengths of time, of diabetic renal disease. Finally, because food choices may be severely restricted on high-protein diets, healthful foods such as low-fat milk products, cereals, grains, fruits, and vegetables (which are higher in carbohydrates and contain essential nutrients) are also generally restricted or eliminated. This can lead to deficiencies in essential vitamins, minerals, and fiber over the long term; these deficiencies can have adverse health effects if they are allowed to persist. Furthermore, when carbohydrates

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are severely restricted with high-protein diets, fatigue often occurs when muscle glycogen is depleted during bouts of exercise. Some popular high-protein/lowcarbohydrate diets limit carbohydrates to 10 to 20 g/d, which is one fifth of the minimum 100 g/d that is necessary to prevent loss of lean muscle tissue. A popular premise of high-protein diets is that excess carbohydrate results in elevated insulin levels, which in turn promotes storage of body fat and other metabolic consequences. To induce weight loss, the high ratio of protein and fat to carbohydrate purportedly promotes metabolic changes that reduce serum insulin levels. However, in fact, protein intake also stimulates insulin secretion. Insulin resistance or hyperinsulinemia is complex and regulated by a number of interacting factors. It occurs as a result of obesity or excess fat storage and lack of physical activity, and it can be reduced significantly by caloric restriction, weight loss, and exercise. Changes in calorie balance over wide ranges of fat intake apparently do not influence insulin action in humans... Deleterious effects on cardiovascular disease risk factors were demonstrated in a study of 24 obese individuals who followed the Atkins diet for 3 months, in whom caloric intake declined but LDL cholesterol levels rose despite the weight loss. Most of the weight loss occurred in the first few weeks, which suggests the combined effects of fluid loss and potential anorectic effects of induced ketosisâ&#x20AC;Śâ&#x20AC;ŚHowever, when carbohydrate is restricted, subjects generally reduce their overall intake of calories, and this calorie deficit is related to the weight loss. These studies raised important questions regarding the long-term effects of these diets on weight maintenance and overall healthâ&#x20AC;Ś Guidelines for Evaluating High-Protein Diets In evaluating high-protein diets, it is important to ensure that eating patterns follow the AHA Dietary Guidelines and incorporate primary prevention strategies for coronary heart disease, such as those outlined by the National Cholesterol Education Program, especially in persons with multiple risk factors, including obesity: 1. Total protein intake should not be excessive (average 50 to 100 g/d) and should be reasonably proportional (15% of kilocalories per day) to carbohydrate (55% of kilocalories per day) and fat (30% of kilocalories per day) intake. 2. Carbohydrates should not be omitted or severely restricted. A minimum of 100 g of carbohydrate per day is recommended to ensure overall nutritional adequacy through the provision of a variety of healthful foods. 3. Selected protein foods should not contribute excess total fat, saturated fat, or cholesterol. 4. The diet should be safely implemented over the long term, i.e., it should provide adequate nutrients and support dietary compliance with a healthful eating plan to prevent increases in disease risk.

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Summary Scientific studies do not demonstrate that high-protein diets without concomitant decreases in caloric intake result in sustained weight loss or improved health. Most Americans consume more protein than their bodies need. Extra protein is not used efficiently by the body and may impose a metabolic burden on the kidneys and liver. High-protein diets may also be associated with increased risk for coronary heart disease due to intakes of saturated fat, cholesterol, and other associated dietary factors. When diets high in protein are severely limited in carbohydrates, food choices become restrictive, and overall nutrient adequacy and long-term palatability are also of concern. Successful weight loss occurs most frequently when a nutritionally adequate diet that allows for caloric deficits (500 kcal/d for each 1 lb lost per week) is tailored according to individual food preferences. A minimum of 1200 kcal/d for women and 1500 kcal/d for men should be provided. Total energy deficit has the greatest overall impact on weight reduction, especially when coupled with increased physical activity and behavior modification to maintain negative energy balance. Over the long term, diet composition should be consistent with a balanced eating plan that supports weight maintenance and lowers chronic disease risk.” (St Jeor et al., American Heart Association 2001). 3. Physicians Committee for Responsible Medicine (PCRM) On the topic of HPLC diets, the PCRM states: “There is a myth that pasta, bread, potatoes, and rice are fattening, but nothing could be further from the truth. Carbohydrate-rich foods are perfect for permanent weight control because they contain less than half the calories of fat, which means that replacing fatty foods with complex carbohydrates automatically cuts calories. It’s important to remember to eat healthy carbohydrates, such as whole grains, pasta, brown rice, and sweet potatoes. Processed carbohydrates, such as white bread and white rice, are not as healthy a choice because they have lost much of their fiber and other nutrients... High-protein diets are associated with many health risks, ranging from mild (constipation, headache, and bad breath) to significant (impaired kidney function, osteoporosis, heart disease, diabetes, and cancer.” (PCRM 2011). Other PCRM publications have commented on HPLC diets: “Studies of general populations consuming diets high in fat, particularly saturated fat... have shown increased risk of cancer, diabetes, and heart disease. Mixed diets high in animal protein have been shown to increase the risk of kidney problems, osteoporosis, and some types of cancer. These studies raise concerns as to whether low-carbohydrate diets, which are typically high in saturated fat and animal protein, might pose the same risks. In addition, because fiber is found only in plant foods, and high-protein, high-fat, carbo-

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hydrate-restricted diets tend to be low in plant foods, these diets are also typically low in fiber. In studies of general populations, low fiber intake is associated with increased risk of colon cancer and other malignancies, heart disease, diabetes, and constipation. Again, these studies raise the question as to whether similar problems occur in low-carbohydrate dieters. Some high-protein, very-low-carbohydrate, weight-loss diets are designed to induce ketosis. When carbohydrate intake or utilization is insufficient to provide glucose to the cells that rely on it as an energy source, ketone bodies are formed from fatty acids. An increase in circulating ketones can disturb the bodyâ&#x20AC;&#x2122;s acid-base balance, causing metabolic acidosis. Evidence suggests that even mild acidosis can have potentially deleterious consequences over the long run, including low blood phosphate levels, resorption of calcium from bone, increased risk of osteoporosis, and an increased propensity to form kidney stones. These findings raise concerns that high-protein, high-fat, low-fibre, carbohydrate-restricted diets used for prolonged periods may increase the risk of health problemsâ&#x20AC;? (PCRM 2004). 4. US Department of Agriculture, US Department of Health and Human Services In the Dietary Guidelines for Americans 2010, the following statements refer to HPLC diets: â&#x20AC;&#x153;Does macronutrient proportion make a difference to body weight? Strong evidence shows that there is no optimal proportion of macronutrients that can facilitate weight loss or assist with maintaining weight loss. Although diets with a wide range of macronutrient proportions have been documented to promote weight loss and prevent weight regain after loss, evidence shows that the critical issue is not the relative proportion of macronutrients in the diet, but whether or not the eating pattern is reduced in calories and the individual is able to maintain a reduced-calorie intake over time. The total number of calories consumed is the essential dietary factor relevant to body weight. In adults, moderate evidence suggests that diets that are less than 45 percent of total calories as carbohydrate or more than 35 percent of total calories as protein are generally no more effective than other calorie-controlled diets for long-term weight loss and weight maintenance. Therefore, individuals who wish to lose weight or maintain weight loss can select eating patterns that maintain appropriate calorie intake and have macronutrient proportions that are within the AMDR ranges recommended in the Dietary Reference Intakes. Individual foods and beverages and body weight For calorie balance, the focus should be on total calorie intake, but intake of some foods and beverages that are widely over- or under-consumed has been associated with effects on body weight. In studies that have held total calorie intake constant, there is little

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evidence that any individual food groups or beverages have a unique impact on body weight. Although total calorie intake is ultimately what affects calorie balance, some foods and beverages can be easily over-consumed, which results in a higher total calorie intake. As individuals vary a great deal in their dietary intake, the best advice is to monitor dietary intake and replace foods higher in calories with nutrient-dense foods and beverages relatively low in calories. The following guidance may help individuals control their total calorie intake and manage body weight: • Increase intake of whole grains, vegetables, and fruits: Moderate evidence shows that adults who eat more whole grains, particularly those higher in dietary fiber, have a lower body weight compared with adults who eat fewer whole grains. Moderate evidence in adults and limited evidence in children and adolescents suggests that increased intake of vegetables and/or fruits may protect against weight gain.” (US Department of Agriculture, US Department of Health and Human Services 2010). In Your Guide to a Healthy Heart, the US Department of Health and Human Services states: “The currently popular high-fat, low-carbohydrate diets promise quick, dramatic weight loss. But they’re not the route to healthy, long-term weight management. A diet high in fat, especially if it is high in saturated fat, is not good for your heart. These diets are also high in protein and can cause kidney problems and increased bone loss. Highfat, low-carb diets are also low in many essential vitamins, minerals, and fiber. While some people following this type of a diet lose weight in the short term, much of the weight loss is due to water loss. As with most quick-fix diets, the weight tends to quickly return once you stop dieting. The best course is to steer clear of all fad diets. The healthiest, most effective route to long-term weight loss is a lower fat, lower calorie, well-balanced diet.” (US Department of Health and Human Services 2005). 5. National Heart Foundation of Australia In the Position Statement on Very low-carbohydrate Diets, the National Heart Foundation of Australia writes extensively against the use of very low-carbohydrate (VLCARB) diets: “VLCARB diets derive a considerable proportion of energy from saturated fat and little from plant foods such as vegetables and whole grain cereals that may have cardioprotective effects. Given this, there is concern that these diets are a higher cardiovascular risk. Other research suggests that higher dietary protein loads may compromise renal function in susceptible people and accumulation of ketones may result in bone demineralisation and impaired liver and kidney function... The high saturated fat content of VLCARB diets is another concern. Meals high in saturated fat can have acute effects on the impairment of endothelium-dependent vasodilation, which is an early marker of atherosclerosis. In cross sectional studies, the saturated fatty acid composition of serum lipids, partly reﬂecting the composition of dietary saturated fat consumed, is associated with endothelial dysfunction in apparently healthy subjects...

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The VLCARB dietary pattern is also nutritionally variable and potentially incomplete. Folic acid, dietary ﬁbre and calcium are some of the key nutrients in VLCARB diets that do not meet the Australian Recommended Dietary Intake levels. These diets' low folate intake may exacerbate plasma homocysteine concentrations which, in turn, may impact adversely on the atherosclerotic process... Based on current available evidence, the Heart Foundation does not support the adoption of VLCARB diets for weight loss. We believe that this dietary pattern does not provide optimal cardiovascular risk reduction or nutritional adequacy... VLCARB diets high in saturated fat are not recommended for long-term weight loss or for cardiovascular risk reduction.” (National Heart Foundation of Australia 2004). British Dietetic Association (BDA) The British Dietetic Association has published a fact sheet entitled Confused about Carbohydrates?: “Eating too little carbohydrate may lead to low blood sugar levels (hypoglycaemia) which can leave us feeling weak and light headed. It can also make it difficult to concentrate as the ability to think and learn comes from an adequate supply of fuel to the brain. Hypoglycaemia is a particular risk for some people with diabetes who are on tablets or insulin. It can also affect very active sports people, who may feel exhausted when their blood sugar and muscle glycogen stores run low. If we eat too little carbohydrate, over time our body will begin to use up some stored fat but quickly moves on to burning its own protein tissue such as in the heart and muscles. A low intake of wholegrain cereals, fruit and vegetables rich in indigestible carbohydrate or NSP (non-starch polysaccharides) can also lead to bowel problems such as constipation. Research shows that in the long term high carbohydrate diets are the most beneficial for health. Dietary guidelines advise that we should be getting about half of our energy intake from carbohydrate. We should eat more starchy foods (e.g. bread, rice, pasta, breakfast cereals, oats and chapattis) preferably in wholegrain forms.... ...Starchy foods are good sources of energy and fibre but they also contain calcium, iron and B vitamins... Aren't carbohydrates fattening? If we take in more food energy than we burn up, no matter what the source, the excess will be converted to fat... Sometimes people mistakenly think starchy foods such as bread and potatoes are fattening. However weight for weight carbohydrates contain less than half the calories of fat and studies show they are much better at satisfying our hunger. Watch out for the added fats used for cooking and serving, because it is these that increase the calorie content (e.g. fried potatoes).

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Can low-carbohydrate diets help with weight loss? 'Low-carbohydrate' diets which cut out most starchy foods are sometimes used for weight loss. In the short term they can lead to side effects such as constipation, headache, bad breath and nausea. In the longer term cutting out any food group can be bad for health because you risk missing out on vital nutrients. 'Low-carbohydrate' diets tend to be higher in fat, and eating a high fat diet (especially one rich in saturated fat from foods such as meat, cheese, cream and butter) could increase the chances of developing heart disease. Low carbohydrate diets may also restrict the amount of fruit, vegetables and fibre, all of which are vital for good health including reducing cancer risk.” (BDA 2008). The British Dietetic Association has gone on to publish more statements on specific HPLC diets. In fact the Dukan diet featured in its “annual top five worst celebrity diets to avoid in the New Year”: “The Dukan Diet is Offal! There is absolutely no solid science behind this at all. This works on restricting foods, calories and portion control again... This diet is so confusing, very rigid, full of very French foods that most Brits would run a mile from like rabbit and offal, and even Mr Dukan himself warns of the associated problems like lack of energy, constipation and bad breath.” (BDA 2011a). The BDA has more statements regarding low-carbohydrate diets on NHS Choices, the UK's largest health website. It includes the Dukan Diet: “you may experience side effects such as bad breath, a dry mouth, tiredness, dizziness, insomnia and nausea from cutting out carbs. The lack of wholegrains, fruit and veg in the early stages of the diet could cause problems such as constipation... The Dukan diet isn't nutritionally balanced, which is acknowledged by the fact that you need a vitamin supplement and a fibre top up in the form of oat bran. There's a danger that this type of diet could increase your risk of longterm health problems...” On the Atkins diet: “side effects include bad breath, a dry mouth, tiredness, dizziness, insomnia, nausea and constipation from cutting out carbs and fibre. The high intake of saturated fat may increase your risk of heart disease and there are concerns that the lack of fruit, veg and dairy products and a high protein intake may affect bone and kidney health long term... The Atkins diet isn't nutritionally balanced. By limiting fruit and veg it contradicts all the advice on healthy eating that we have tried so hard to pass on to people.” (BDA 2011b). 7. Food Standards Agency The Food Standards Agency advice on diet is contrary to HPLC diets, in that “increased consumption of starchy foods (such as bread, potatoes, pasta and rice) and infrequent consumption of high fat and/or sugar foods are important in achieving a healthy balanced diet” (Food Standards Agency 2011).

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8. Heart and Stroke Foundation of Canada In the Heart and Stroke Foundation of Canada's position statement on low-carbohydrate diets they state: “Do not follow a low-carbohydrate diet for purposes of weight loss. These diets tend to be high in saturated and trans fats... • Foods with carbohydrate have important vitamins and minerals like vitamin C, iron, calcium, folic acid, potassium, and magnesium. Eliminating carbohydrates from your diet can put you at risk for vitamin and mineral deficiencies. • Foods with carbohydrate, for example whole grain breads and brown rice, are an important source of fibre which can help reduce cholesterol, improve your bowel function, and promote blood sugar control. • low-carbohydrate diets allow very low amounts of carbohydrates – typically less than 20% of total calorie intake (less than 100 grams of carbohydrate per day, some as low as 20 grams per day). Thus, individuals have a higher intake of fat and protein, often above the intake recommended by Health Canada. • Eating a diet higher in fat (more than 35% of your total daily calories), particularly higher in saturated and trans fat, will increase your risk of heart disease and stroke. • Eating habits that will lower your risk for heart disease and stroke include eating a high-fibre, lower-fat diet, eating 5 to 10 servings of vegetables and fruit per day, and eating portion sizes of food that are in line with your level of physical activity.” (Heart and Stroke Foundation of Canada 2004). 9. American Dietetic Association The American Dietetic Association is an international authority on nutrition. In their book, the American Dietetic Association's Complete Food and Nutrition Guide, the section on HPLC diets states: “The facts are... simply because these diets are lower in calories, they may promote weight loss – if you stick to them... A high-protein diet doesn't build muscle and burn fat, as some people think. Only regular physical activity and training build muscle strength and burn calories found in body fat... For most people, a low-carbohydrate, high-protein eating approach for weight loss raises concerns: - These diets do promote rapid weight loss – at first. Their diuretic effect promotes loss of water weight, not body fat, however. The psychological lift offers a false sense of success that's quickly gone when water weight returns. −

Depending on the foods consumed, a high-protein, low-'carb' diet may be high in total fat, saturated fat, and cholesterol. Inconsistent with sound nutritional advice, the weight loss regime can increase the risk for heart disease and perhaps some forms of cancer.

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A diet that restricts many starchy foods is often low in fiber. The possible result? Constipation and other gastrointestinal disorders. A low-fiber diet isn't consistent with guidelines for health.

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A condition called ketosis (increased blood ketones from incomplete fat breakdown) can result from these regimes... in truth, muscle also breaks down due to a lack of carbohydrate for energy. In addition ketosis can cause weakness, nausea, dehydration, light headedness, and irritability. It can be fatal to people with diabetes, and during pregnancy may cause birth defects or fetal death.”

Myth: Potatoes and bread are fattening Fact: By themselves, they're not high in calories – 88 for a medium (4 oz) potato and 70 calories for an average slice of bread. However high-fat toppings or spreads can add extra calories. Myth: Excess 'carbs', not fats, cause weight gain. Fact: Excess carbohydrates are no more fattening than excess calories from any source: fats, carbohydrates or proteins. Despite claims of 'low-carb' weight loss regimens, a high-carbohydrate diet doesn't promote body fat storage by enhancing insulin resistance. Excess calories from any source are stored as body fat.” (Duyff, American Dietetic Association 2006). 10. American Cancer Society The American Cancer Society guidelines on diet bear no relation to HPLC diets: “Eat a healthy diet, with an emphasis on plant foods. • Choose foods and drinks in amounts that help you get to and maintain a healthy weight. • Limit how much processed meat and red meat you eat. • Eat at least 2½ cups of vegetables and fruits each day. • Choose whole grains instead of refined grain products... Overall, diets that are high in vegetables, fruits, and whole grains (and low in red and processed meats) have been linked with lower colorectal cancer risk (American Cancer Society 2011). 11. Physicians' Guide to Popular Weight Loss Diets Expert doctors in the field of obesity have published numerous reports on HPLC diets. For example in the Physicians’ Guide to Popular Weight Loss Diets, co-written by the chair of the North American Association for the Study of Obesity, HPLC diets are reviewed and condemned at length (Blackburn et al. 2001). A few of the final summarising paragraphs are included here, remarking on the need for doctors to monitor “dizziness, headaches, fatigue, irritability, gout, and kidney failure. Laboratory work includes routine blood tests (glucose, blood urea nitrogen, sodium, potassium, chloride,

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and bicarbonate), urinalysis (specific gravity, pH, protein, and acetone), and lipid profile… What to tell patients on a low-carbohydrate diet Initial ‘fast’ weight lost is water, not fat These diets are deficient in nutrients that cannot be replaced by supplements and are excessive in nutrients that may increase the risk of mortality and disease These diets are difficult to adhere to because they lack variety and increase the desire to consume high-carbohydrate, high-fat foods. It is very difficult to stay on a diet that includes less than 100g of carbohydrate per day in the long term, considering that the typical American diet contains about 275g/day Ketogenic diets are associated with adverse effects. A diet low in fruits, vegetables, and whole grains increases the risk of heart disease, cancer, and stroke There is no evidence that low-carbohydrate diets are effective for long-term weight management, and their long-term safety in questionable and unproven” 12. Low-carbohydrate–high-protein diets. Is there a place for them in clinical cardiology? Cardiologists have also analysed HPLC diets and renounced them for being no more effective than traditional low-fat diets, and being dangerous, partly due to the excessive levels of saturated fat and cholesterol (Kappagoda et al. 2004). In a paper entitled, Lowcarbohydrate–high-protein diets. Is there a place for them in clinical cardiology? HPLC diets are criticised as follows: “There are several reports of impairment of endotheliumdependent relaxation during postprandial lipemia. In addition, postprandial lipemia is associated with increased markers of inflammation and activation of platelets and monocytes. Thus, repeated high-fat meals are likely to generate a persistent state of impaired endothelium-dependent relaxation and other atherogenic processes... In conclusion, use of LC-HP diets run counter to all the current evidence-based dietary recommendations for healthy populations. These diets do not meet the nutritional requirements of healthy people based on current dietary reference intakes for many vitamins and minerals and recommendations for dietary fibre. When used for weight loss, these diets are associated with several potential adverse effects and nutrition deficits, and the long-term consequences of their continued use are unknown. On the basis of evidence currently available, LC-HP diets cannot be recommended as part of a longterm care plan for weight management in patients who smoke or have common diseases that affect the cardiovascular system, such as hypertension, hyperlipidaemia, diabetes mellitus, and coronary atherosclerosis vascular disease, where endothelial dysfunction is a feature.”

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An excellent resource on the science and medical consequences of HPLC diets is a website collated by an Amercian general practitioner, Dr Michael Greger, called www.atkinsexposed.com. He is a founding member of the American College of Lifestyle Medicine, and an internationally recognised lecturer on nutrition and food safety issues. There is an extensive section on expert medical opinions which I recommend, as it includes statements (all highly critical) from numerous international health bodies on HPLC diets: the American Cancer Society, American Dietetic Association, American Heart Association, American Institute for Cancer Research, American Kidney Fund, American Medical Association, Centre for Science in the Public Interest, Cleveland Clinic, Consumer Guide, Cornell University Cooperative Extension, Mayo Clinic, Northwestern University School of Medicine, Partnership for Essential Nutrition, Physicians' Committee for Responsible Medicine, Tufts University School of Nutrition, UC Berkley School of Public Health, and United States Department of Agriculture. There are also many reviews by senior physicians, and published studies in peer-reviewed journals.

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12. MORTALITY AND HPLC DIETS: ARE THERE EFFECTIVE HEALTHY ALTERNATIVES? Ageing and chronic disease Oxidative damage to tissues increases during both ageing (Barja 2002) and ageing-related chronic diseases such as cancer and cardiovascular disease (Benzie 2000). Ageing is caused by the accumulation of free radical-induced oxidative damage to components of the cell. It is possible to limit oxidative damage with antioxidants, which enhance DNA, protein and lipid protection by increasing the scavenging of oxidative radicals and repairing cell damage. Oxidative damage products can be measured in order to examine the relationship to diet. For example one study in women in their sixties found that the vegetarians had significantly lower levels of oxidative damage products (oxidized DNA breaks, oxidized fatty acids and oxidized proteins) than non-vegetarian women (Krajcovicova-Kudlackova et al. 2008). Furthermore, levels of vitamin C and beta carotene were both higher in the vegetarian group. In fact the oxidative damage product levels and antioxidant levels were similar to a comparison group of vegetarian women in their twenties. In contrast, the non-vegetarians all showed significant deleterious changes in these two measures with age. These findings concur with the knowledge that adequate consumption of antioxidant and phytochemical-rich foods such as fruit and vegetables, whole grains, pulses, seeds and plant oils (staples of a vegetarian diet) protect against degenerative diseases (Key et al. 2006). Indeed, research has reported that protective food consumption is significantly higher in vegetarians compared with non-vegetarians (fruit 463 vs. 176 g/day, vegetables 195 vs. 62 g/day, whole grains 242 vs. 65 g/day, pulses 38 vs. 6 g/day, nuts 29 vs. 7 g/day, and plant oils 63 vs. 32 g/day) (Krajcovicova-Kudlackova et al. 2004). The results of these studies suggest that the increase in oxidative damage in ageing and the pathogenesis of degenerative diseases may be prevented by plant-based protective foods. HPLC diets, which limit carbohydrates and hence plant-based protective foods, are also rich in pro-oxidant haem iron and pro-inflammatory arachidonic acid: they actually have the potential to increase oxidative damage to tissue macromolecules. The consequences of this are a speeding up of the ageing process and an increased risk of chronic degenerative diseases. Ageing, caloric restriction and protein restriction There are four methods which research has demonstrated to cause an increase in lifespan: genetic manipulation, caloric restriction, protein (methionine) restriction, and the drug rapamycin. Concentrating on the latter three methods, they all share a common pathway: a reduction in the amount of protein in terms of either intake or synthesis. It is now thought that the effect of caloric restriction on lifespan is nutrient based. I discussed earlier how caloric restriction is linked to a reduction in exposure to AGEs. Another important factor in the increased longevity seen on calorie restricted diets is a reduction

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in the amount of protein. The experiments and mechanisms to support this are discussed below. Studies in fruit flies have demonstrated that lowering the protein:carbohydrate ratio of the diet increases lifespan. In one experiment, flies were allowed access to one of 28 different diets, with varying ratios of yeast to sugar (Lee et al. 2008). The flies which lived the longest were those on a diet containing a 1:16 protein:carbohydrate ratio. They lived progressively less long as the protein:carbohydrate ratio increased. This result was repeated in other experiments on fruit flies, again showing that the dietary protein:carbohydrate ratio, and not energy intake, was strongly associated with lifespan (Fanson et al. 2009; Fanson & Taylor 2011). Mammalian studies have dissected which amino acids are responsible for affecting lifespan. They report significantly increased lifespan on diets absent in cysteine and restricted in methionine in both rat studies (Orentreich et al. 1993; Zimmerman et al. 2003) and mice studies (Miller et al. 2005). Note that both of these are sulphurcontaining amino acids, found in abundance in animal protein, and hence in abundance in traditional HPLC diets. The Miller et al. study not only demonstrated maximal lifespan on a methionine restricted diet, but it also examined in detail the metabolic effects. The experimental mice, on a 0.15% methionine diet (compared to control mice on a 0.43% methionine diet), had 75% lower insulin levels, 50% lower glucose levels, lower cataract scores, reduced age related changes in T cells, and hepatocytes which were more resistant to oxidative damage. They also weighed 40% less, despite food intake per g of body mass being higher than the control mice. This experiment is of great relevance to HPLC diets, as they are high in the amino acid which is linked to reduced longevity. Furthermore, oxidative damage, cataracts, diabetic changes and weight gain are associated with diets containing higher levels of methionine. In summary, shortened lifespan occurs when protein is eaten in higher than optimal quantities relative to non-protein energy. What are the potential mechanisms? A review paper on the topic of macronutrient balance and lifespan discussed the evidence (from numerous animal studies examining protein restriction) for how a high amino acid:glucose ratio can lead to early death (Simpson & Raubenheimer 2009). It states that the mechanisms are: 1. Enhanced production of mitochondrial radical oxygen species and changes to mitochondrial metabolism. 2. Increased protein and DNA oxidative damage, processes associated with ageing and cancer. 3. Changes in membrane fatty acid composition. 4. Toxic effects of nitrogenous breakdown products. 5. Reduced capacity to deal with dietary toxins. 6. Changes in immune function to pathogenic attack. 7. Changed functioning of circadian rhythms. 8. Changes in the relationship between insulin/IGF and amino acid signaling pathways, including TOR.

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The TOR (target of rapamycin) pathway is a signaling mechanism resulting in anabolic responses such as protein synthesis, lipogenesis, cell proliferation, cell size, growth, and reproduction. It operates via effects on the regulation of mRNA translation, autophagy, stress response pathways and mitochondrial function. Prolonged activation of TOR is associated with insulin resistance and inhibition of autophagy and repair. Furthermore, it has been linked to enhanced ageing, and has also been implicated in a number of ageassociated diseases such as cardiovascular disease, type 2 diabetes, cancer, and neurodegenerative diseases (Stanfel et al. 2009). Amino acids are known to activate TOR. In fact, TOR stimulation depends on circulating nutrients, needing a high amino acid:glucose ratio (Simpson & Raubenheimer 2009). In HPLC diets, the conditions are perfect for chronic stimulation of TOR, and hence the degenerative diseases associated with age and early death. In contrast, reduced TOR signaling is a feature of caloric restriction, which is known to dramatically delay the onset of age-associated diseases in animal studies. A low amino acid:glucose ratio (i.e. the opposite of an HPLC diet) stimulates the AMPK (adenosine 5'-monophosphate (AMP)-activated protein kinase) signaling pathway and depresses TOR activity. AMPK is an important regulator of both lipid and glucose metabolism, and is considered to be a key therapeutic target for the treatment of obesity, type 2 diabetes mellitus, and cancer. The net result is improved insulin sensitivity, promotion of autophagy and repair, and the triggering of catabolic responses such as cell cycle arrest, proteolysis, lipolysis, and inhibition of growth: all factors contributing towards living longer. Further proof of the importance of inhibition of the TOR pathway in order to increase longevity, comes from experiments in animals using the drug rapamycin. This is an immunosuppressant drug, used to prevent transplant rejection, and is now in trials for the treatment of cancer. It also happens to act as an inhibitor of the TOR pathway, and has been shown to prolong life in invertebrates and mice by up to 14% (Harrison et al. 2009). Its potential to retard the mechanisms of ageing is now the subject of intense research. One of the keys to living longer is, it seems, to reduce the protein to carbohydrate ratio or to reduce the amount of methionine in the diet, enough to prevent all the negative effects of excess protein on the metabolism, and enough to depress the TOR pathway and stimulate the AMPK pathway. HPLC diets have the opposite effect, and epidemiological data on mortality provides more evidence for their detrimental effect on lifespan. Overall mortality of low-carbohydrate diets All of the above evidence indicates that HPLC diets are not the healthiest of diets. To back this up, I would like to draw attention to a Harvard study published in 2010, funded by the National Institutes of Health, looking at low-carbohydrate diets and all-cause and cause-specific mortality (Fung et al. 2010). This was a huge study with 85,168 women and 44,548 men, drawn from the Nurses Health Study and Health Professionals' Followup Study. The women were followed up from 1980 to 2006 and the men from 1986 to

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2006, none of whom had heart disease, diabetes or cancer at baseline. Low-carbohydrate diets, either animal-based (animal sources of fat and protein) or vegetable-based (vegetable sources of fat and protein), were computed from several validated foodfrequency questionnaires. The results showed that the overall low-carbohydrate score was associated with a modest increase in overall mortality. The animal low-carbohydrate score was associated with higher all-cause mortality, cardiovascular mortality and cancer mortality. In contrast, a higher vegetable low-carbohydrate score was associated with lower all cause mortality and cardiovascular mortality. From this data alone, I would urge any health professional or commercial weight loss programme to reconsider the use of HPLC diets, unless vegetable protein is emphasised over animal protein. Long-term survival studies have also been conducted on European populations. A Swedish study on 42,237 healthy women, followed up for 12 years, found that carbohydrate restriction and high protein consumption increased the overall mortality rate, particularly due to cardiovascular disease (Lagiou et al. 2007). For every decrease in decile for carbohydrate intake there was an increase in overall mortality of 6%, and for every decile increase in protein there was an increase in total mortality of 2%, for all women aged 29-49. Combined, this resulted in an increase in total mortality in all women of 23% with an intake of the top 2 protein deciles and the bottom 2 carbohydrate deciles. For women aged 40-49, the cardiovascular mortality increased by 13%, for every decile decrease in carbohydrate, and increased by 16% for every decile increase in protein. The mortality gradient was steep. Thus any protein intake over the bottom 2 deciles combined with carbohydrate intake below the top 2 deciles, resulted in an increased risk of cardiovascular disease of 45% in women aged 40-49. Once the lowest carbohydrate and highest protein intake (bottom 2 deciles and top 2 deciles respectively) were reached, cardiovascular mortality was increased in all women by 2.38 times, and in women aged 40-49 this was 3.86 times higher. Confounding factors such as BMI, smoking, age, energy intake, saturated fat intake, education, exercise and alcohol were all controlled for. Even more alarmingly, the levels of protein and carbohydrate intake were not as extreme as HPLC diets. For example, the 10th centile of carbohydrate intake was 32% of total energy intake, and the 90th centile of protein intake was 23% of energy intake. HPLC diets, which have even lower levels of carbohydrate (less than 15%) and higher levels of protein (30%), would be expected to increase all cause and cardiovascular mortality even more. Conversely, the macronutrient composition associated with the lowest mortality was the opposite extreme: a carbohydrate intake of 72% and a protein intake of 10%. The authors noted that HPLC diets may be acceptable if the protein is of plant origin and the carbohydrates which are reduced are simple and refined ones, but traditional HPLC diets do not specify this. “The biomedical plausibility of our ﬁndings is considerable. Vegetables, fruits, cereals and legumes, which have been found in a number of studies to be core components of healthy dietary patterns, are important sources of carbohydrates and reduced intake of these food groups is likely to have adverse health effects. Increased meat consumption and high protein intake are also discouraged on account of empirical ﬁndings, pathophysiological arguments (stemming from the positive association between protein intake and insulin like growth factor1 (IGF-1) blood levels) and practical considerations (restriction of healthy foods).”

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A 10 year Greek study on 22,944 healthy individuals from the EPIC cohort, evaluating diet composition and general population statistics, discovered a similar finding: lower carbohydrate and higher protein intakes were associated with increased mortality, particularly due to cardiovascular disease, and to a lesser extent with cancer (Trichopoulou et al. 2007). As in the Swedish study, the mortality gradient was steep: for every increase in protein by 15 g a day, and decrease in carbohydrate by 50 g a day, there was a 22% increased risk of mortality. This higher risk reached 71% in people in the lowest decile of carbohydrate and highest decile of protein intake combined, controlling for overall energy intake. There was also an increased mortality with saturated fat intake: for every decile increase in saturated fat there was an 8% increase in mortality. Conversely, high carbohydrate and low protein intake was associated with reduced mortality, as was a higher unsaturated fat intake. For example for every decile increase in carbohydrate intake there was a 6% reduced risk of mortality. For every decile increase in unsaturated fat, there was 7% reduced risk of mortality. Analysis was repeated on two separate groups of individuals who had either coronary heart disease or type 2 diabetes, and the association between the HPLC dietary pattern and mortality was even stronger. The message is that to improve survival, HPLC diets are to be avoided, particularly if they contain saturated fat. A high-carbohydrate diet with adequate protein, and including unsaturated fat, maximises lifespan. These findings are supported by reports which state that vegetarians live on average between 3 and 6 years longer than non-vegetarians (Enas et al. 2003). One of the key factors in determining the increased mortality with traditional HPLC diets is the presence of red and processed meat. A prospective study on 121,342 individuals found that red meat consumption increased total mortality by 13%, cancer mortality by 10%, and cardiovascular mortality by 18%. Consumption of processed meat produced even worse statistics: total mortality was increased by 20%, cancer mortality by 16%, and cardiovascular mortality by 21% (Pan et al. 2012). Life expectancy and diet A study looking at international life expectancy figures found that the longest-living people in the world are vegetarian California Seventh Day Adventists: men and women have expected ages at death of 83.3 and 85.7 years respectively. These figures are greater than the California population by 9.5 and 6.1 years respectively. Furthermore, the vegetarians also had lower body mass indexes than the general population (Fraser 2001). These figures are even higher than the Okinawa Japanese, who, with a life expectancy of 81.2 years, used to have the highest life expectancy in the world (Harvard Health Letter 2002). The centenarians of Okinawa have been extensively studied in terms of health. For example, blood levels of free radicals (lipid peroxides) are very low. Rates of heart disease, cancer, hip fractures, dementia are much lower than in the west: mortality statistics reveal that compared with Okinowa, USA death rates from coronary heart disease are 11.8 times higher in women and 5.8 times higher in men; bowel cancer is 3.1 times higher in women and 1.9 times higher in men; prostate cancer is 7 times higher;

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and breast cancer is 5.5 times higher. (Willcox et al. 2009). The Okinawa Centenarian Study states â&#x20AC;&#x153;Elderly Okinawans were found to have impressively young, clean arteries, low cholesterol, and low homocysteine levels when compared with Westerners... have about 40% fewer hip fractures than Americans... an average body mass index (BMI) that ranged from 18 to 22.â&#x20AC;? (Okinawa Centenarian Study 2011). What is it about the Okinawa diet which may help to prevent chronic disease? It has much in common with a vegetarian diet: the traditional Okinawa diet is notable for having 7 portions of fruit and vegetables a day, large amounts of soya (80 g a day), and being low in fat, most of which is unsaturated (Willcox et al 2009). It is reduced in meat and fish (only eaten on holidays), refined grains, sugar, salt and dairy products. A typical day consists of sweet potato and miso (soya) soup with plenty of vegetables, for breakfast, lunch and dinner. Sweet potato, the staple carbohydrate, is particularly nutritious, containing high concentrations of vitamin A, C, E, thiamine, riboflavin, vitamin B6, trypsin inhibitors, polyphenols and anthocyanins. The latter three nutrients are very potent antioxidants. Furthermore, sweet potatoes are known to increase insulin sensitivity without increasing insulin secretion, to increase levels of adiponectin, and to decrease cholesterol and LDL cholesterol: thus they are both anti-atherogenic and antiinflammatory. Any HPLC diet should include sweet potato to benefit from its superior nutritional profile. The overall nutritional composition of the Okinawa diet is very high in carbohydrate and very low in fat. In fact data from 1912 revealed that it contained 91.2% (546 g) carbohydrate, 1.7% (4.4 g) fat, and 7.1% (42.4 g) protein (Sho 2001). Since the 1960's the diet has changed to include less sweet potato and a little more rice and bread, but it is still high in carbohydrate and low in fat: 58% carbohydrate, 27% fat (7% saturated fat), and 13% protein i.e. the opposite of an HPLC diet! Healthy alternatives HPLC diets Having outlined the flaws of traditional HPLC diets, and their side effects, is there an effective healthy alternative? As most of the medical consequences of HPLC diets stem from the consumption of animal protein and animal fat, it is logical to devise a diet minimising meat consumption: the key is to reduce saturated fat. There are two approaches to this question: devising a low saturated fat diet, high in complex carbohydrates, or adapting an HPLC diet to include plant-based protein and plant-based fats. Examples of the former approach are the Ornish diet, Dr Fuhrman's Eat to Live diet, and the Fleming diet (all mentioned earlier), which have beneficial effects in terms of lowering cholesterol and improving endothelial and heart health, as previously discussed. The latter approach has also been tested, with good medical outcomes. For example, a ketogenic diet, high in polyunsaturated fat, has been devised as an alternative to traditional ketogenic diets (used in epileptic children), which are high in saturated fat (known to have adverse effects on cholesterol and insulin signaling) (Fuehrlein et al. 2004). This particular diet was tested in healthy volunteers, and after only 5 days plasma glucose levels decreased, triglycerides decreased, insulin sensitivity increased, with no rise in total cholesterol or LDL cholesterol. In comparison, the traditional ketogenic diet

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caused total cholesterol and LDL cholesterol to increase, glucose levels did not reduce, and insulin sensitivity did not improve. The traditional ketogenic diet (15% carbohydrate, 15% protein, 70% fat: 60% saturated, 25% monosaturated, 15% polyunsaturated) comprised of ham, pepperoni, beef, chicken, cheese, cream cheese, ice cream, crackers, oil, and a few green vegetables. The polyunsaturated ketogenic diet had the same macronutrients, except there was 60% polyunsaturated fat and 15% saturated fat. This had soya 'bacon', soya nuts, walnuts, chicken, turkey, soya milk, pitta bread, oil, and a few green vegetables, thus having the advantage of containing no cancer-promoting processed meats, and much less saturated fat. Substituting polyunsaturated fat for saturated fat is preferable for any diet, particularly if followed long term, in order to obtain the benefits of improving insulin sensitivity and reducing total and LDL cholesterol. However, I do not approve of a diet containing 70% fat, even if the source is healthy, as it appears that the beneficial effect of fat quality on insulin sensitivity is not seen at levels of intake of over 37% (Vessby et al. 2001). Furthermore, at a level of only 15% carbohydrate it would be impossible to include the recommended minimum of fruit, vegetables and whole grains required to prevent cardiovascular disease and cancer, and to provide adequate vitamins, minerals, fibre and phytochemicals. A healthier variation on the HPLC theme was devised by Jenkins and colleagues in order to reduce weight and improve plasma lipids (Jenkins et al. 2009). This “Eco-Atkins” diet comprised of vegetable proteins from gluten (55%), soya (23%), fruits and vegetables (9%), nuts (7%) and cereals (6%), with additional fruits and vegetable oils. All the foods were provided to the participants of the study: a special high protein nut “bread” made from ground almonds, hazelnuts and wheat gluten, plus soya/gluten burgers, veggie “bacon”, and deli slices. Tofu and soya milk were included. Nuts provided 44% of the total fat (almonds, cashews, hazelnuts, macadamia, pecans and pistachios); 24% came from vegetable oils; and 19% from soya products. (The rest derived from avocado, cereals, fruits and vegetables). The macronutrient composition is listed in Table 12.1. Table 12.1. Nutritional composition of a high-carbohydrate lacto-ovo vegetarian diet and a low-carbohydrate vegan diet High-carb (lacto-ovo) Low-carb (plant) Calories 1488 1451 Carbohydrate (%) 58 27 Protein (%) 17 30 Vegetable protein 7 30 Soya protein 0.2 7 Fat (%) 25 43 Saturated 5 6 Monosaturated 8 25 Polyunsaturated 9 10 Fibre (g/1000 kcal) 21 28 Cholesterol (mg/1000 kcal) 30.1 0.4

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It was more balanced than traditional HPLC diets, containing the recommended minimum of carbohydrate of 130 g/day, an impressive 41 g of fibre, very little saturated fat, and almost no cholesterol. It was essentially an HPLC vegan diet, and was compared with a high-carbohydrate lacto-ovo vegetarian diet. After 4 weeks both diets resulted in the same weight loss and beneficial effects, but with significantly greater beneficial effects with the plant-based HPLC diet, as seen in Table 12.2. Table 12.2 Weight loss and biochemical parameter results after 4 weeks on a highcarbohydrate lacto-ovo vegetarian diet and a low-carbohydrate vegan diet High-carb (lacto-ovo) Weight loss, kg 4 Plasma cholesterol (%) -12.7 LDL cholesterol (%) -12.3 Triglycerides (%) -17.8 Apolipoprotein B -13.2 Satiety score (-4 to +4) 0.8 Blood pressure reduced+ Fasting glucose reduced Insulin concentration reduced Insulin resistance reduced

Low-carb (plant) 4 -19.8 -20.4 -29.2 -21.1 1.5 reduced++ reduced (no sig. difference between groups) reduced (no sig. difference between groups) reduced (no sig. difference between groups)

Here we can see that the â&#x20AC;&#x153;Eco-Atkinsâ&#x20AC;? plant-based HPLC diet was successful for weight loss, in addition to lowering plasma lipids, glucose, and insulin. It is a much healthier alternative to traditional HPLC diets because it contains enough carbohydrate for the healthy function of brain, blood and renal cortex cells, and also the carbohydrates allowed (oats and barley), together with the low-starch vegetables, provide 7 g of viscous fibre per 2000 kcal: the level recommended to lower cholesterol. Traditional HPLC diets cause cholesterol and LDL cholesterol to increase, as discussed earlier. Another way of finding out an effective healthy alternative to HPLC diets is to analyse the dietary composition of people with the lowest BMI. Research on existing dietary habits demonstrates that BMI values are lower in vegetarians, and lower still in vegans compared with meat eaters (Spencer et al. 2003; Newby et al. 2005; Barnard et al. 2005; Fraser 2009; Tonstad et al. 2009; Craig 2010). For example, data from the Adventist Health Study 2 cohort (n=89,224) reports that vegetarians have an average BMI of over 2 points lower and vegans over 5 points lower than meat eaters: the mean BMI was 28.26 for meat eaters (meat more than once a week), 27 for semivegetarians (meat less than once a week), 25.73 for pescovegetarians (fish not meat), 25.48 for lactoovovegetarians (no meat or fish, but have dairy and eggs) and 23.13 for vegans (no meat, fish or dairy) (Fraser 2009).

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The biggest study of European vegans (looking at over 1,000) reported that less than 2% were obese (Spencer et al. 2003). Compare this to the rate of obesity in English adults of 24% (men) and 25% (women) (NHS Information Centre, Lifestyles Statistics 2010). Furthermore, a review of 40 studies associated people who are vegetarian or vegan with having reduced body weight (Berkow & Barnard 2006), on average between 3 kg and 13 kg less than meat eaters (up to 20% slimmer). The authors concluded that this was due to the low-fat and high-fibre content of diets: the fibre decreasing the energy density of the food, and also leading to reduced energy intake due to increased satiety. Low glycaemic index foods also high in fibre (plant foods such as oats and legumes) increase satiety and lead to a reduction in voluntary food intake (Barnard et al. 2009; Ludwig 2000; Howarth et al. 2001). A higher intake of fibre is linked to a reduced BMI (Appleby et al. 1998). For example, research shows that the leanest men and women have a significantly higher fibre intake of 27 and 22.7 g/day respectively, compared with obese men and women (22 and 15 g/day) (Miller 1994). Note that a typical HPLC diet such as the Atkins diet has only 5 to 10 g/day of fibre. On the topic of devising a healthy and effective weight loss diet, what has research discovered about plant-based diets? Having already ascertained the safety of plant-based diets, they are certainly effective in reducing weight: many studies demonstrate that weight loss is more effective when choosing a vegetarian diet (Rosell 2006; Barnard et al. 2005; Barnard et al. 2006). The Barnard et al. 2005 study compared a low-fat vegan diet (10% fat, 15% protein, 75% carbohydrate) with a more conventional low-fat diet (less than 30% fat, less than 7% saturated fat, 15% protein, more than 55% carbohydrate) (Table 12.3). The vegan dieters ate a selection of fruit, vegetables, grains and legumes, with an added vitamin B12 supplement. No animal foods were allowed. Table 12.3. Nutritional composition of a low-fat vegan diet after 14 weeks, compared to baseline kcal protein carbohydrate simple sugars fat saturated fat cholesterol fibre

Baseline 1774 71g 232g 81g 62g 21g 230mg 21g

14 weeks 1408 42g 274g 82g 18g 3g 17mg 30g

The subjects were requested not to restrict portion sizes or to do exercise, although both groups ended up spontaneously reducing calories to 1400 calories a day. After 14 weeks, the vegan dieters had lost more weight (5.8 kg versus 3.8 kg), but how could this be explained when both groups were eating the same number of calories? One explanation is that the vegan group had a raised resting basal metabolic rate, and an increase in the thermic of effect of food (the after-meal calorie burning speed, measured at regular intervals from 10 minutes to 2 hours 50 minutes post ingestion of a test meal), compared

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with the non-vegan dieters. The thermic effect is due to improved insulin sensitivity, causing the body’s cells to be able to extract glucose more quickly from the blood. It is interesting that the weight loss occurred with no conscious limit on energy intake. It seems that the vegan food was not only lower in calorie density, but it was also more filling. As the researchers noted, “hunger is not part of the equation”. A breakdown of the nutritional analysis of the diets (Table 12.3) reveal that the nutritional content of the more successful diet is the opposite of an HPLC diet: lower protein, higher carbohydrate, and lower fat, with extremely favourable reductions in saturated fat and cholesterol. The Barnard et al. 2006 study (also quoted by the Royal College of Physicians and NICE publication on type 2 diabetes), compared type 2 diabetics on either a low-fat vegan diet or a standard American Dietetic Association (ADA) diet for diabetes. After 22 weeks, the weight loss for the vegan group was 6.5 kg, with a reduction in the waist/hip ratio, versus 3.1 kg and no reduction in waist/hip ratio in the ADA group. 43% of the vegan group were able to reduce their diabetic medication versus 26% in the ADA group. The reductions in HbA1c levels, total cholesterol and LDL cholesterol were all dramatically reduced in the vegan group compared with the ADA group, in those whose medication had remained stable. Dr Ornish's Lifestyle Heart Trial, mentioned earlier for demonstrating the ability of a 10% fat vegetarian diet to reverse heart disease, coincidentally discovered substantial weight loss on the diet (11 kg in one year). This was achieved on 1821 kcal, and only 6% (13 g) fat a day. After 5 years, the value increased slightly to 1846 kcal, with the nutritional content being only 8.5% fat (17 g of fat a day), 18.6 mg of cholesterol, 15% protein (69 g), and 76.5% carbohydrate (353 g). Again we can see remarkable weight loss on a diet opposite in nature to an HPLC diet. Dr Ornish states that it is correct that we eat too many simple carbohydrates in the form of cakes, biscuits, chocolate, sweetened cereal, crisps, and chips, but the solution is not to cut out carbohydrates completely, but to switch to complex carbohydrates such as wholewheat, brown rice, whole grains, fruit, vegetables and legumes. In this way the dietary fibre is increased, which slows down carbohydrate absorption and prevents rapid rises in blood sugar. Furthermore, the less fat that is eaten, the fewer calories are consumed without having to eat less food, as fat contains 9 kcal/g compared with 4 kcal/g of protein or carbohydrate. One can eat when hungry until satiated, and still lose weight. The goal is to eat less fat and less sugar.

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13. WORLD HEALTH ADVISORY BODIESâ&#x20AC;&#x2122; STATEMENTS ON PLANTBASED DIETS Having established the effectiveness of a plant-based diet in terms of losing and maintaining weight loss, is it healthy to follow such a programme long term or for life? What do the world's health advisory bodies say on the matter of plant-based diets? These are some of the health statements that have been made over the past few years: 1. British Medical Association (BMA) In the BMAâ&#x20AC;&#x2122;s report on diet, nutrition and health, it said "Vegetarians have lower rates of obesity, coronary heart disease, high blood pressure, large bowel disorders, cancers and gallstones. Cholesterol levels tend to be lower in vegetarians." It went on to say that when meat eaters change to a vegetarian diet it can actually lower their cholesterol levels. It concluded by saying that vegetarians obtain all the minerals they need, that folate levels are higher, and as a consequence it is a diet suitable for infants (British Medical Association 1986). 2. World Health Organisation (WHO) The World Health Organisation has published several reports on diet and chronic diseases such as cardiovascular disease, diabetes and cancer. For example, Diet, Nutrition and the Prevention of Chronic Diseases states: â&#x20AC;&#x153;Changes in the world food economy are reflected in shifting dietary patterns, for example, increased consumption of energy-dense diets high in fat, particularly saturated fat, and low in unrefined carbohydrates.... Diet has been known for many years to play a key role as a risk factor for chronic diseases. What is apparent at the global level is that great changes have swept the entire world since the second half of the twentieth century, inducing major modifications in diet, first in industrial regions and more recently in developing countries. Traditional, largely plant-based diets have been swiftly replaced by high-fat, energy-dense diets with a substantial content of animal-based foods... The adverse dietary changes include shifts in the structure of the diet towards a higher energy density diet with a greater role for fat and added sugars in foods, greater saturated fat intake (mostly from animal sources), reduced intakes of complex carbohydrates and dietary fibre, and reduced fruit and vegetable intakes... Excessive consumption of animal products in some countries and social classes can, however, lead to excessive intakes of fat... The growing demand for livestock products is likely to have an undesirable impact on the environment. For example, there will be more large-scale, industrial production, often

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located close to urban centres, which brings with it a range of environmental and public health risks. Attempts have been made to estimate the environmental impact of industrial livestock production. For instance, it has been estimated that the number of people fed in a year per hectare ranges from 22 for potatoes and 19 for rice to 1 and 2, respectively, for beef and lamb. The low energy conversion ratio from feed to meat is another concern, since some of the cereal grain food produced is diverted to livestock production.”(WHO 2003) The WHO's latest report Global Strategy on Diet, Physical Activity and Health states: “For diet, recommendations for populations and individuals should include the following: - limit energy intake from total fats and shift fat consumption away from saturated fats to unsaturated fats and towards the elimination of trans-fatty acids. - increase consumption of fruits and vegetables, and legumes, whole grains and nuts… Fruit and vegetables are important components of a healthy diet, and their sufficient daily consumption could help prevent major diseases, such as cardiovascular diseases and certain cancers… Insufficient intake of fruit and vegetables is estimated to cause around 14% of gastrointestinal cancer deaths, about 11% of ischaemic heart disease deaths and about 9% of stroke deaths globally. A recently published WHO/FAO report recommends a minimum of 400g of fruit and vegetables per day (excluding potatoes and other starchy tubers) for the prevention of chronic diseases such as heart disease, cancer, diabetes and obesity, as well as for the prevention and alleviation of several micronutrient deficiencies, especially in less developed countries.” (World Health Organisation 2012). What else does the WHO say that we should be eating? They state that a healthy diet should be based on 55-75% carbohydrates (e.g. complex starchy carbohydrates such as bread, rice, pasta, potatoes, yams etc. with no need for sugar at all), 15% to 30% fat, (less than 10% saturated fat) and 10-15% protein. (World Health Organisation 2003). As an aside I would like to comment on the recommended protein intake. Human breast milk, which contains all the protein necessary for health and growth, contains only 1.3 g of protein per 100 g, and protein comprises only 7.5% of its calories. Again this makes us question the need for a diet with a higher percentage of protein. Interestingly, it has been claimed that a person could live on a diet of Marmite, wholemeal bread, margarine and oranges, although a more varied diet is obviously recommended!

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3. Heart and Stroke Foundation “Vegetarian diets can provide all the nutrients you need at any age, as well as some additional health benefits. Vegetarian diets often have lower levels of total fat, saturated fat and cholesterol than many meat-based diets, and higher intakes of fibre, magnesium, potassium, folate and antioxidants such as vitamins C and E. Vegetarian diets may lead to lower blood pressure, improved cholesterol levels, healthier weight and less incidence of Type 2 diabetes, all of which can reduce the risk of heart disease and stroke... Plant-based foods can provide all the protein you need. Protein-rich plant foods include: -all soy products such as tofu, tempeh and beverages -cooked beans, peas and lentils -peanuts and peanut butter -most nuts and seeds It is no longer necessary to combine proteins for example, beans with grains, in the same meal in order to maximize protein absorption... Vegetarians are at no more risk of iron deficiency than meat eaters.”(Heart and Stroke Foundation 2011). 4. European Prospective Investigation into Cancer and Nutrition (EPIC) Study In 1992 the largest ever study of diet and health was initiated - the European Prospective Investigation into Cancer and Nutrition. More than half a million people have been studied in 10 European countries, including the UK. There are two EPIC centres in the UK, at Oxford and Cambridge Universities. The EPIC-Oxford study includes a total of around 65,000 participants of whom half are vegetarian and 2,500 are vegan. Ongoing analysis of the results shows that non-meat diets tend to reduce blood pressure levels, cholesterol levels and the incidence of obesity: “on average they have a relatively low BMI and a low plasma cholesterol concentration… vegetarians have a moderate reduction in mortality from ischaemic heart disease” (Key et al. 2006). 5. Physicians Committee for Responsible Medicine (PCRM) The PCRM, a highly respected US body which numbers the late Dr Benjamin Spock and William Roberts, editor of the American Journal of Cardiology amongst its 5,000 doctors and scientists, regularly issues reports to the US government and general population on health and diet, based on the latest scientific reviews: “Vegetarian diets, which contain no meat (beef, pork, poultry, or fish and shellfish), are naturally low in saturated fat, high in fiber, and full of vitamins, minerals, and cancerfighting compounds. A multitude of scientific studies have shown that vegetarian diets have remarkable health benefits and can help prevent certain diseases, such as cancer, diabetes, and heart disease. We encourage vegetarian diets as a way of improving general health and preventing diet-related illnesses.

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Vegan diets, which contain no animal products (meat, dairy, eggs, or other animal products), are even healthier than vegetarian diets. Vegan diets contain no cholesterol and even less fat, saturated fat, and calories than vegetarian diets because they exclude dairy and eggs. Scientific research shows that health benefits increase as the amount of food from animal sources in the diet decreases, making vegan diets the healthiest overall.” (PCRM 2012). Dr Neal Barnard, president and founder of the PCRM states that “… chicken-and-fish diets are not low enough in fat or cholesterol to do what vegetarian diets can…. all have cholesterol and more fat than is found in typical beans, vegetables, grains, and fruits, virtually all of which are well under 10 per cent fat. So while white-meat diets lower cholesterol by only about five per cent, meatless diets have three to four times more cholesterol-lowering power, allowing the arteries to reopen.” (Barnard 2003). 6. US Department of Health and Human Services In the document Dietary Guidelines for Americans 2010, there are important statements about diet and weight loss: “Placing individual eating choices into an overall eating pattern Foods high in water and/or dietary fiber typically have fewer calories per gram and are lower in calorie density, while foods higher in fat are generally higher in calorie density. A dietary pattern low in calorie density is characterized by a relatively high intake of vegetables, fruit, and dietary fiber and a relatively low intake of total fat, saturated fat, and added sugars. Strong evidence shows that eating patterns that are low in calorie density improve weight loss and weight maintenance, and also may be associated with a lower risk of type 2 diabetes in adults… When choosing carbohydrates, Americans should emphasize naturally occurring carbohydrates, such as those found in whole grains, beans and peas, vegetables, and fruits, especially those high in dietary fiber, while limiting reined grains and intake of foods with added sugars. Glycaemic index and glycaemic load have been developed as measures of the effects of carbohydrate-containing foods and beverages on blood sugar levels. Strong evidence shows that glycaemic index and/or glycaemic load are not associated with body weight; thus, it is not necessary to consider these measures when selecting carbohydrate foods and beverages for weight management… Whole grains are a source of nutrients such as iron, magnesium, selenium, B vitamins, and dietary fiber. Whole grains vary in their dietary fiber content. Moderate evidence indicates that whole grain intake may reduce the risk of cardiovascular disease and is associated with a lower body weight. Limited evidence also shows that consuming whole grains is associated with a reduced incidence of type 2 diabetes. Some of the best sources of dietary fiber are beans and peas, such as navy beans, split peas, lentils, pinto beans, and black beans. Additional sources of dietary fiber include

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other vegetables, fruits, whole grains, and nuts. All of these foods are consumed below recommended levels in the typical American diet. Dietary fiber that occurs naturally in foods may help reduce the risk of cardiovascular disease, obesity, and type 2 diabetes. Children and adults should consume foods naturally high in dietary fiber in order to increase nutrient density, promote healthy lipid profiles and glucose tolerance, and ensure normal gastrointestinal function… Animal fats tend to have a higher proportion of saturated fatty acids… Consuming less than 10 percent of calories from saturated fatty acids and replacing them with monounsaturated and/or polyunsaturated fatty acids is associated with low blood cholesterol levels, and therefore a lower risk of cardiovascular disease. Lowering the percentage of calories from dietary saturated fatty acids even more, to 7 percent of calories, can further reduce the risk of cardiovascular disease… Cholesterol is found only in animal foods… Dietary cholesterol has been shown to raise blood LDL cholesterol levels in some individuals… Moderate evidence shows a relationship between higher intake of cholesterol and higher risk of cardiovascular disease… Consuming less than 300 mg per day of cholesterol can help maintain normal blood cholesterol levels. Consuming less than 200 mg per day can further help individuals at high risk of cardiovascular disease… Research on vegetarian eating patterns In prospective studies of adults, compared with non-vegetarian eating patterns, vegetarian-style eating patterns have been associated with improved health outcomes— lower levels of obesity, a reduced risk of cardiovascular disease, and lower total mortality. Several clinical trials have documented that vegetarian eating patterns lower blood pressure. On average, vegetarians consume a lower proportion of calories from fat (particularly saturated fatty acids); fewer overall calories; and more fiber, potassium, and vitamin C than do non-vegetarians. Vegetarians generally have a lower body mass index. These characteristics and other lifestyle factors associated with a vegetarian diet may contribute to the positive health outcomes that have been identified among vegetarians.” (US Department of Health and Human Sciences 2010). 7. American Diabetes Association “Plant-based diets (vegan or vegetarian) that are well planned and nutritionally adequate have also been shown to improve metabolic control. The primary goal with respect to dietary fat in individuals with diabetes is to limit saturated fatty acids, trans fatty acids, and cholesterol intake so as to reduce risk for CVD. Saturated and trans fatty acids are the principal dietary determinants of plasma LDL cholesterol.” (American Diabetes Association 2010) 191

8. American Cancer Society (ACS) The ACS has published the American Cancer Society Guidelines on Nutrition and Physical Activity for Cancer Prevention. In the section on vegetarian diets it states: “Do vegetarian diets reduce cancer risk? Vegetarian diets can include health promoting features. They tend to be low in saturated fat and high in fibre, vitamins, and phytochemicals, and do not include eating red and processed meats. Thus, it is reasonable to suggest that vegetarian diets may be helpful in lowering cancer risk.” (ACS 2011). 9. American Dietetic Association (ADA) The ADA is one of the most respected health bodies in the world, and in its most recent report on vegetarianism, has said that: “Vegetarian or vegan diets, are healthful, nutritionally adequate, and may provide health benefits in the prevention and treatment of certain diseases. Well-planned vegetarian diets are appropriate for individuals during all stages of the life-cycle, including pregnancy, lactation, infancy, childhood, and adolescence, and for athletes.” (Craig & Mangels, American Dietetic Association 2009). The ADA also makes clear that vegetarian diets can provide all the vitamins, minerals, protein and energy the body needs: “protein, n-3 fatty acids, iron, zinc iodine, calcium, and vitamins D and B12. A vegetarian diet can meet current recommendations for all of these nutrients...a vegetarian diet is associated with a lower risk of death from ischemic heart disease. Vegetarians also appear to have lower low-density lipoprotein cholesterol levels, lower blood pressure, and lower rates of hypertension and type 2 diabetes than non-vegetarians. Furthermore, vegetarians tend to have a lower body mass index and lower overall cancer rates. Features of a vegetarian diet that may reduce risk of chronic disease include lower intakes of saturated fat and cholesterol and higher intakes of fruits, vegetables, whole grains, nuts, soy products, ﬁbre... magnesium and potassium, vitamins C and E, folate, carotenoids, flavonoids and other phytochemicals.”

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14. OTHER RECOMMENDATIONS FOR HPLC DIETS AND CONCLUSION I have a concern that defendants of HPLC diets will say "It's only for a few weeks". I am afraid that messages such as "eat bacon freely", "cheese is good", and "fruit is bad" will linger for ever in dieters' minds: they will attempt to apply the principles of an HPLC diet long-term, with all the potential medical dangers detailed above. As an obesity expert, I have encountered numerous patients who have become “carbophobic”, and who actually say that they will “never give up HPLC dieting” and that it is “a way of life”. I have even come across patients who are so convinced that “carbohydrates are unhealthy”, that they have stopped giving carbohydrates to their own young children, with complete disregard for their unique nutritional properties and their necessity for growth, and brain and metabolic function. They are oblivious of the fact that detrimental vascular changes are seen after just a few weeks on a low-carbohydrate diet. I would recommend less strict carbohydrate restriction than typical HPLC diets for nutritional purposes. Any diet containing less than 100 g of carbohydrate a day is ketogenic, and HPLC diets contain considerably less than this. A more generous carbohydrate allowance would mean that fruit could be included, with ketosis still taking place. Furthermore, as the brain is a carbohydrate-dependent organ, there would be less risk of impaired judgement, especially if carbohydrate was allowed in the morning. So long as the carbohydrates have a low glycaemic load, a low insulin score, and a high satiety rating (for example, porridge, apples, oranges), there is no risk of increased cravings. Patients attending obesity clinics will be on appetite suppressants anyway to banish such cravings. Increasing the carbohydrate content to 100 g a day would also prevent loss of muscle mass, as mentioned earlier. In terms of recommended oils, any reference to safflower and sunflower oil should be ignored, because they have an exceedingly poor ratio of omega 6 to omega 3 fatty acid (safflower oil has no omega 3 at all, and more omega 6 than any other oil). Also it should be stated that the only oils suitable for cooking are macadamia nut oil and extra-virgin olive oil, and even then they should not be heated above 180 degrees centigrade, to avoid the formation of trans fats. HPLC diets should recommend a variety of different carbohydrates once target weight has been reached. Modest quantities of brown rice can be consumed, incorporated into traditional meals, with the benefits of higher-quality nutrition, stronger feelings of fullness, and more successful weight maintenance, compared with white rice. The benefits of wholemeal bread should also be emphasised, as this is actually a high-protein food, with 19% protein and only 8% fat. (Eating nothing but wholemeal bread until one satisfied one's protein's needs would lead to substantial weight loss!) Any vegetarian HPLC diet should omit any reference to fish. If there is a meat-free diet which contains fish, then it is accurately called “pescatarian”. No diet should omit a section on exercise. This should observe current Department of Health Guidelines, which state that adults should do 30 minutes of moderate exercise five

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times a week (Department of Health 2007). In fact the National Obesity Forum recommends that for weight loss, 60 minutes of moderate exercise, five times a week, should be undertaken (National Obesity Forum 2006). This can be spaced out over the day e.g. six 10-minute bouts. Exercise has the added benefit of protecting against certain cancers such as colorectal cancer (convincing evidence of reduced risk), postmenopausal breast cancer and endometrial cancer (probable reduced risk), and lung, pancreatic, and premenopausal breast cancer (suggestive reduced risk) (WCRF/AICR 2007). Conclusion My own conclusion, based on the extensive medical evidence outlined above, is that HPLC diets only work by reducing calories, and do not cause greater weight loss longterm than healthier low-fat diets. (Short-term much of the weight loss is due to water). It is not necessary to go into ketosis to burn fat: it is simply a sign that fat is being burned incompletely. Excess dietary protein (above 45 to 70 g a day, depending on height) cannot be stored in the body and is just converted into fat and carbohydrate anyway: one might as well have eaten the banned carbohydrate food in the first place, thus benefiting from its vitamins, minerals, fibre, antioxidants and phytochemicals. (Exercise determines muscle mass, not large quantities of protein.) Animal protein such as meat, cheese and eggs causes satiety, but not as much as equal calories of wholegrain pasta, apples, oranges, porridge or boiled potatoes. Quorn has less fat, less saturated fat, lower calories and is more filling than chicken. The medical consequences of HPLC diets are related to them containing too much animal proteins, saturated fats and cholesterol, too little fibrous complex carbohydrates, and not enough fruit, vegetables or whole grains. Typical HPLC diets are associated with increased risks of dehydration; headaches; lethargy; general weakness; loss of concentration; low mood; halitosis; nausea; constipation; muscle cramps; metabolic acidosis; loss of muscle mass; hypothyroidism; hypoglycaemia; vitamin and mineral deficiencies including low levels of thiamine, folate, vitamin C, iron, sodium, potassium, magnesium, calcium, zinc, selenium, and copper; high levels of uric acid (causing gout); high levels of blood ammonia (causing neurological impairment); optic neuropathy; cardiac arrhythmias; hypercholesterolaemia; hypertriglyceridaemia; cardiovascular disease; cardiomyopathy; diabetes; cancer; endotoxaemia; irritable bowel syndrome; inflammatory bowel disease; gall stones; renal stones; renal failure; osteopenia, osteoporosis and fractures; Alzheimerâ&#x20AC;&#x2122;s disease; Parkinsonâ&#x20AC;&#x2122;s disease; haem iron toxicity; a greater susceptibility to infectious diseases; advanced ageing; and increased mortality. HPLC diets in pregnancy are associated with increased rates of foetal death and lowered IQ in the surviving children. Conversely, HPLC diets based on plant-based proteins and including a minimum of 130 g of whole grain carbohydrates a day (to preserve brain function) are not associated with these side effects, diseases or a reduced lifespan. In fact plant-based diets are known to actually reverse heart disease. An HPLC diet should only be followed short-term (for no more than a few days), and only if it includes a minimum of three servings of whole grains; seven and a half 194

portions of fruit and vegetables; pulses, including soya products; minimal saturated fat, cholesterol, and trans fats; and minimal animal protein. A diet of 1500 kcal a day should contain at least 35% carbohydrate (all unrefined), equivalent to 130 g a day (necessary for brain function), and at least 23 g of fibre a day. This should include soluble fibrecontaining foods such as peas and beans, oats and barley, apples and pears, broccoli, carrots, sweet potatoes and onions. Protein intake should be limited to 28%, equivalent to a maximum of 105 g a day if it is animal protein (there is less risk of renal failure with plant-based proteins). Soya protein is a “complete” protein, of the same maximal quality as milk and egg white. Fat content should be no more than 37% (mostly unsaturated), equivalent to 62 g, for optimal insulin function. Such an “alternative” HPLC diet is an alkali-forming, anti-inflammatory, anti-cardiovascular disease, anti-cancer weight-loss diet. It should preferably be based on plant protein such as pulses, nuts, and seeds, and then be called a truly “medical” diet. Due to its optimum nutritional quality, and the fact that it observes guidelines for the prevention of high cholesterol and cancer, it could be followed long-term without ill effect. However, ideally a weight-loss diet should be both reduced in calories and balanced, consisting of adequate amounts of fibrous complex carbohydrates, plant-based protein, and unsaturated fat. The reduced calories are achieved by cutting out refined carbohydrates, sugar, saturated fat, cholesterol, and trans fats.

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PART 3: A HEALTHY AND EFFECTIVE DIET FOR WEIGHT LOSS 15. THE 5:15 DIET Any individual wishing to lose weight can devise their own diet, based on the healthy principle of eating wholegrain, plant-based foods, and sticking to the “5:15” rule. This means eating nothing containing more than 5 g of fat per 100 g, and no more than 1500 calories a day. The rule is relaxed for the inclusion of healthy fats such as flaxseed oil, walnut oil, nuts and seeds, up to a maximum of 50 g a day of nuts, seeds and oils. I have devised such a diet based on the “5:15” rule. It is balanced, with healthy amounts of protein, fat, and carbohydrate, and can thus be followed long-term. If an individual is determined to do an HPLC diet, as a “kick start” (for initial rapid water loss), then meals based on fake meats, soya products, beans, nuts, seeds, fruit and vegetables can be consumed for up to one week, before embarking on the more balanced 5:15 diet which contains whole grains. My plant-based diet has no cholesterol, and does not have the potential of leading to any of the problems associated with animal-based proteins. However, if it is preferable for an individual not to follow an exclusively plant-based diet, modifications can be made, provided that the only additions are small quantities of Quorn, low-fat dairy products and free range eggs. My suggested lacto-ovo meals could be used occasionally as an alternative to the plant-based diet if desired. The key is to keep the fat content as close to 5 g of fat per 100 g as possible. The lacto-ovo choices contain modest quantities of saturated fat, animal protein and cholesterol, but are still preferable to a typical HPLC diet, which contains excessive amounts of these macronutrients. Quorn is available from all supermarkets, in both the fridge and freezer sections. I recommend doing one hour of exercise a day in total, which can achieved by accumulating several bouts of a few minutes throughout the day. Walking is just as good as cycling, swimming, weights machines, gym classes, or doing an exercise DVD. The key is to choose an enjoyable form of exercise, to aid long-term commitment. I have personally followed the plant-based 5:15 diet, resulting in 2 kg weight loss in four weeks, achieving a BMI of 19.5. My fat percentage has gone down, and my muscle mass has gone up, despite no extra exercise. There are no hunger pangs at all. I am now still following this diet, adjusting the portion sizes in accordance with long-term weight maintenance. Carbohydrate The key is to eat controlled amounts of three different types of fibrous complex carbohydrates, spread out throughout the day, in order to maintain steady blood-sugar levels and to satisfy brain requirements. This technique helps to eliminate the urge to binge on sweet or refined carbohydrate food, which is common when following HPLC diets. No white carbohydrates or sugar are allowed. It is particularly important to

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â&#x20AC;&#x153;carbohydrate loadâ&#x20AC;? in the morning, providing the brain with a plentiful supply of glucose after the overnight fast. Aim to eat up to 40 g of carbohydrate per serving. Choose three of the following foods, one serving to be eaten at each meal time (suggestions for accompaniments are given in the menu section): 1 bowl of muesli (40 g) 1 bowl of porridge (using 40 g of oats) 2 slices of wholemeal bread 1 wholemeal bagel 1 wholemeal wrap 1 wholemeal pitta bread 1 medium-sized potato (175 g), baked or steamed 1 medium-sized sweet potato (175 g), baked or steamed 1 spool of whole wheat noodles (50 g dry weight) 1 heaped tablespoon of brown rice (40 g dry weight) 1 heaped tablespoon of quinoa (40 g dry weight) 1 heaped tablespoon of wholegrain pasta (40 g dry weight) 1 heaped tablespoon of barley (40 g dry weight) Protein Women should aim to eat around 50 g of protein per day, and men around 60 g per day. Individuals wishing to gain muscle mass through weight training may consume 20 g more. The essential requirement is to include pulses every day in the form of beans, lentils, chickpeas and/or soya products such as soya mince, tofu or soya fake meats. All fake meats should contain less than 5 g of fat per 100 g. Choose two or three from the following, during the whole day: Beans e.g. chick peas or haricot, borlotti, red kidney, black-eyed, aduki, mung or broad beans. Have a portion of 240 g (1 tin), which provides approximately 20 g of protein. Lentils e.g. red (dried, and only 10 minutes to cook) or brown/green lentils (tinned). Have a 240 g portion. Soya mince, dried e.g. Neal's Yard savoury soya protein mince (available in Holland and Barrett). Have a 40 g portion (132 kcal; 21 g of protein). Soya mince, frozen e.g. Linda McCartney vegemince or supermarket own brand frozen meat-free mince. Have a 150 g portion (160 kcal; 20 g of protein). 1 traditional vegetarian burger e.g. Fry's (available in Holland and Barrett) (110 kcal; 12.6 g of protein).

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RealEat chicken style pieces (available in Holland & Barrett). Have a 100 g portion (136 kcal; 29 g of protein). Remember that of all the carbohydrate-containing foods, bread contains the highest amount of protein (19%). Fat Nuts and seeds contain essential fatty acids and vitamin E, and are proven to lower cholesterol. The highest concentration of omega 3 fatty acids is found in linseeds and walnuts. Salad dressings can be made using 1 dessert spoon (10 g) of walnut oil or flaxseed oil, mixed with a dash of balsamic vinegar. Store the oil in the fridge. When frying, only use extra virgin olive oil, as it is the only oil which does not turn to trans fats on heating (and even then it must be kept under 180 degrees centigrade). Use a non-stick pan to minimise the amount of oil needed. When choosing a spread, Flora Pro-Active is low in calories and also lowers cholesterol. If preferred, walnut oil can be drizzled on bread instead. As fats contain 9 kcal per g, it is advised to consume no more than 50 g of nuts, seeds and oils a day while trying to lose weight. Fruit and vegetables Eat unlimited vegetables and up to 4 portions of fruit a day. Any vegetable or fruit is allowed (no need to avoid root vegetables, sweetcorn, grapes or bananas). Aim to eat a rainbow of colours in a day e.g. red, orange, yellow, green and purple, which will ensure a full range of antioxidants and phytochemicals. Steaming is the best cooking method as it preserves vitamins better than boiling or microwaving. A portion is 80 g, and to prevent cancer, it is necessary to eat at least 7 Â˝ portions a day (600 g a day). In fact it is helpful to think of the diet as a â&#x20AC;&#x153;5:10:15â&#x20AC;? diet: no more than 5 g of fat per 100g; at least 10 different types of fruit and vegetables a day, and no more than 1500 calories a day. Snacks Avoid crisps, biscuits, cakes and chocolate as they have no nutritional value and add excessive amounts of saturated and trans fats and sugar. Highly palatable sugary and fatty food is also known to be addictive (Johnson & Kenny 2010). Opt for a handful of nuts, seeds or fruit. Choose snacks from the following list: 1 prune and 1 dried apricot 4 cashew nuts. 2 walnut halves 3 brazil nuts A handful of pumpkin seeds A piece of fruit

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Aim to eat no more than 50 g of nuts and seeds a day, to avoid excessive calories. Drinks Try to avoid any extra sugar or fruit juice. The aim is to eat one’s calories not drink them. Avoid alcohol as it provides empty calories, and it lowers the blood sugar the next day which can lead to excessive eating. Coca cola should be avoided due to excessive levels of sugar, caffeine and artificial additives. In exceptional circumstances, caffeine-free diet coke may be consumed in limited quantities. Hot drinks can be made with Alpro light soya milk or Alpro almond milk (both lower calories than skimmed milk). Artificial sweetener can be added if desired (Splenda is the most natural tasting of the sweeteners). Choose from the following list: Water Sparkling water No added sugar squash Diet lemonade Decaffeinated tea (organic if possible) Decaffeinated coffee (organic if possible) Herbal tea Cocoa, made with sweetener, hot water, and a dash of soya milk Supplements Although they are strictly unnecessary, I also choose to take supplements in the form of: 1 kelp tablet: 30 mg – provides 150 mcg iodine (100% RDA). 2 Opti-3 EPA/DHA capsules – provides EPA 200 mg and DHA 400 mg. These are sourced from algae rather than fish, which avoids complications of contamination with pollutants and depletion of the world’s fish stocks. The Opti-3 brand is fortified with vegan vitamin D3 10 mcg (100% RDA), eliminating the need to take an extra vitamin D supplement. (I recommend taking vitamin D if you experience poor sun exposure). The capsules can be ordered from http://www.opti3omega.com/ 1 high-dose vitamin B complex tablet, providing B6, B9 (folate) and B12, in line with research linking high doses of these B vitamin supplements with the prevention of Alzheimer’s disease (Smith et al. 2010).

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16. THE 5:15 MEALS I have compiled a selection of different plant-based meals which offer a wide variety of foods, and can be followed long-term. The portion sizes of this eating plan are designed for weight loss of 0.5 to 1 kg a week (1 to 2 pounds) for individuals with a height of 178 cm (5â&#x20AC;&#x2122; 10â&#x20AC;?). They can be reduced for anyone under this height, if a faster rate of weight loss is desired, in anyone with a sedentary lifestyle, or if taking appetite suppressants. Portion sizes may need to be increased in men or if doing regular intensive exercise. Breakfasts Add 1 piece of fruit to all of the breakfast choices (at the end of the meal for maximum satiety) e.g. fresh berries, one kiwi fruit, one orange, half a grapefruit or some tomato juice. Alpro light soya milk is a delicious and low calorie accompaniment to the cereals (only 22 kcal/100 ml), and has the advantage of being fortified with calcium, vitamin D, vitamin B2 and vitamin B12. Aim for 40 g portions of cereal. For people with a fast metabolism, people who exercise, or if there are any hunger pangs, a low fat vegetarian burger can be added to any of the options. The five most filling breakfasts are: 1. 1 bowl of porridge, made with Alpro light soya milk and sweetener. 2. 1 bowl of no-added-sugar muesli. 3. 1 bowl (60 g) of home-made high-fibre muesli made with equal parts of oat bran, soya bran and wheat germ, topped with dried currants, flaked almonds, pumpkin seeds and linseeds. (This is an excellent cure for constipation, and is very high in omega 3 fatty acids.) 4. 2 slices of Burgen or wholemeal bread and peanut butter, or low-fat spread and reduced-salt yeast extract (which is fortified with vitamin B2, niacin and vitamin B12). 5. 1 bowl of All Bran Other breakfast choices are: 6. 1 bowl of granola with soya yogurt and berries. 7. 1 bowl of Branflakes. 8. 2 Weetabix. 9. 2 Shredded Wheat.

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10. 1 or 2 low-fat vegan burgers (e.g. Fryâ&#x20AC;&#x2122;s) with 1 tbsp of baked beans (drain off most of the sauce). 11. Mixed fruit salad with soya yogurt and sweetener. Lacto-ovo breakfasts The plant-based breakfasts can be adapted for a lacto-ovo diet: 1. Cereal or porridge made with organic skimmed milk (long-life milk is thicker than fresh milk). 2. 2 slices of wholemeal or Burgen bread with 1 free-range boiled egg. 3. Mixed fruit salad with organic low-fat yogurt and sweetener. 4. 1 Quorn quarter pounder burger with 1 tablespoon of baked beans. 5. 1 packet of Quorn bacon style rashers with 1 tablespoon of baked beans.

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Lunches This particular diet contains lunch items which can easily be stored at a work place (for example, tins of pulses and vegetables), the contents of which can then be heated up in a microwave oven. Alternatively, salad prepared at home can be brought in to work, to mix with tinned pulses. This negates the problem of buying lunch items from sandwich bars which are often loaded with excess fat and do not contain enough vegetables. Extra salad vegetables can be added to these meals. Finish lunch with a piece of fruit and/or soya yogurt. Lunch and dinner items can be interchanged. 1. Salad made with 1 tin of beans e.g. butter beans, haricot beans, black-eyed beans or chick peas and at least 4 different types of vegetables. Aim to eat a “rainbow” of colours e.g. tomatoes, carrots, yellow pepper, lettuce, cucumber, celery, and beetroot. Make a dressing high in omega 3 fatty acids of balsamic vinegar and flaxseed oil or walnut oil. 2. 1 wholemeal roll with vegetable soup. Choose a fresh low-fat vegetable soup without cream, or make your own soup using vegetable stock, lentils or soya mince and any vegetables. 3. 1 wholemeal bread sandwich with a plant-based filling e.g. low-fat houmous, falafels, Marmite and cucumber, nut butter (e.g. peanut, cashew or almond butter), or vegetarian pate (available in health food shops or make a vegetarian pate using pureed lentils, herbs and spices). Include some salad with each filling. 4. 1 wholemeal pitta bread with a low-fat filling. 5. 4 rice cakes or 4 Ryvita, plus a low-fat topping. 6. 1 whole wheat wrap. Stuff with mixed beans and grilled peppers, plus salad. 7. 175 g jacket potato with 150 g of baked beans and/or sweetcorn. Drain off most of the sauce with the baked beans, to reduce the sugar content, before heating them up. 8. 2 slices of wholemeal toast with 150 g of baked beans (drain off most of the sauce). 9. Mushrooms on 2 slices of wholemeal toast. Dry fry the mushrooms in a non-stick pan, or use 1 tsp of extra virgin olive oil. 10. 1 vegan burger with a wholemeal bun. 11. 1 tin of pulses (e.g. pease pudding or black-eyed beans) with spinach and tomato purée. 12. 1 tin of drained baked beans with peas and carrots.

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13. 1 Innocent Veg Pot. 14. Ratatouille (tinned or homemade), including onions, courgettes, aubergines, peppers, tomatoes and parsley, plus a wholemeal roll. Lacto-ovo lunches 1. 1 wholemeal bread sandwich with Quorn slices e.g Quorn ham, chicken, peppered beef or turkey and stuffing style slices and salad. 2. 1 wholemeal bread sandwich with Philadelphia extra light soft cheese and salad. 3. 1 wholemeal bread sandwich with half-fat cheddar cheese and avocado. 4. 1 toasted low-fat cheese and tomato sandwich (wholemeal). 5. Poached egg or scrambled egg and spinach on 2 slices of wholemeal toast. 6. Reduced-fat feta cheese salad with 1 potato. 7. 1 tub of low-fat cottage cheese with pineapple with 2 rice cakes or Ryvita. 8. 1 wholemeal wrap with Quorn fajita or steak strips and salad. 9. Quorn and salad (if a â&#x20AC;&#x153;low-carbâ&#x20AC;? lunch is preferred). Have a packet of a Quorn product which can be eaten cold, with salad. The following options are all less than 5 g of fat per 100 g, and are all lower fat, lower calories and more filling than chicken: Quorn slices e.g. ham, chicken, peppered beef, turkey and stuffing style Quorn barbeque or tikka sliced fillets Quorn fajita strips

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Dinners Unlimited extra vegetables can be added to the following meals. Pasta, rice, barley and quinoa portions are 40 g dry weight (equivalent to approximately 150 calories). Uncle Ben’s brown rice takes only 10 minutes to cook. Finish dinner with a piece of fruit and/or soya yogurt. 1. Vegetables and soya mince. Mix 40 g of dried Neal's Yard savoury soya protein mince or 150 g frozen soya mince (e.g. Linda McCartney) with 200g of fresh vegetable soup, and heat in the microwave for 3 to 4 minutes. Extra herbs, spices or a vegetable stock cube can be added. Mix in a selection of steamed vegetables. Serve with brown rice, barley or quinoa, or 1 mediumsized potato. 2. Vegetables and beans. Mixed steamed vegetables, fresh vegetable soup and 1 tin of pulses. Heat up the beans and the soup, and mix in the steamed vegetables at the end. Serve with brown rice, barley or quinoa, or 1 medium-sized potato. 3. Vegetable stir fry. Heat up mixed stir fry vegetables with 1 tsp of extra virgin olive oil in a non-stick wok. Add 1 tin of chick peas or 100 g of tofu or Real Eat ‘chicken style pieces’, and some lowsalt soya sauce. Serve with whole wheat noodles. 4. Vegetable bolognaise Cook onions, garlic, diced courgettes, aubergines and mushrooms. Add 150 g of Linda McCartney frozen meat-free mince or supermarket own brand soya based meat-free mince. Mix with 1 tin of tomatoes, 1 tbsp of tomato puree and oregano, or use a ready made tomato pasta sauce from a jar, and cook for 10 minutes. Serve with wholegrain spaghetti. 5. Vegetable hot pot. Mix beans or lentils together with a selection of chopped cooked vegetables, herbs, and 1 tin of tomatoes. A vegetable stock cube can be added to taste. Put sliced potato on top and bake in the oven. 6. Pulses, peas and pasta. Mix together a selection of tinned pulses with cooked onions and peas and some wholewheat pasta (60 g dry weight). Heat through with herbs and a vegetable stock cube. 7. Bean casserole with jacket potato. Cook chopped vegetables of choice with 1 tin of mixed beans, 1 tin of tomatoes, and 1 vegetable stock cube. Serve with a 175 g jacket potato.

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8. Stuffed courgettes/red peppers. Fill a red pepper or courgette with brown rice, aduki beans or mung beans, peas, tomatoes and raisins. Bake in the oven. 9. Vegetable and lentil curry. Cook onions, garlic, courgettes, aubergines, mushrooms, carrots and celery until soft. Add cooked red lentils and curry powder. Serve with brown rice. 10. Bean and nut roast. Mix together cooked onions, mushrooms, baked beans (drain off most of the sauce) with wholemeal bread crumbs and 40 g of ground mixed nuts. Press into a loaf tin and bake. Serve with steamed vegetables. 11. Vegetable risotto. Cook brown rice with onions, peas, mushrooms, sweetcorn, kidney beans, and courgettes. 12. Veggie burgers and mash. Grill 2 low-fat burgers (e.g. Fryâ&#x20AC;&#x2122;s) and serve with steamed vegetables and mashed potato or sweet potato. Lacto-ovo dinners 1. Quorn option less than 5 g of fat per 100 g. Serve with steamed vegetables and 1 potato. Choose from: 2 Quorn fillets 2 Quorn fillets with tomato and olive sauce 2 Quorn lamb style grills 2 Quorn peppered steaks 1 Quorn quarter pounder burger 2 Quorn beef style and sweet red onion burgers 10 Swedish or Italian style balls 2. Quorn bolognaise. Use diced vegetables, Quorn mince and tomato pasta sauce. Serve with whole wheat spaghetti. 3. Stir fry vegetables and Quorn pieces. Serve with whole wheat noodles. 4. Cauliflower, leek and butter bean cheese bake. Make a sauce using soya or skimmed milk and 30 g of low-fat cheese, and bake in the oven. Serve whole wheat pasta.

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5. Vegetable omelette. Use 1 tsp of extra virgin olive oil, diced mixed vegetables, and 1 or 2 free range eggs. (Donâ&#x20AC;&#x2122;t eat more than 6 eggs a week to avoid excessive cholesterol). 6. Vegetarian ready made meal. There are several brands of low calorie meat-free fresh and frozen meals which are readily available, and are useful if you have not had time to cook e.g. Quorn, supermarket own brand, or Linda McCartney ready made meals, or look in the fridge and freezer of Holland and Barrett. Make sure that the fat content is less than 5 g per 100 g, and aim not to eat more than 300 calories. Serve with extra vegetables.

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17. REAL LIFE DIET CASE STUDIES I have asked a sample number of slim people what they actually eat on a daily basis. None of these people do extra exercise other than walking or occasional cycling. The examples given below, although not exclusively plant-based, follow similar principles to the ones that I advocate. Diet example number 1: weight maintenance This 29 year old woman has maintained a BMI of 19.3 for years. Breakfast: 1 bowl of fruit n' fibre cereal or porridge. 1 banana. Lunch: Noodles, soya pieces and vegetables. Fruit and yogurt for dessert. Dinner: Rice, sweetcorn and mixed vegetables.

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Diet example number 2: weight maintenance This 32 year old woman has maintained a BMI of 20.4 for several years. Breakfast: Plain soya yogurt with honey, plus granola or fruit. Lunch: 2 slices of rye bread with 1 whole avocado or light cheddar cheese. 1 apple. Or: salad containing leaves, cherry tomatoes, celery, cucumber, olives and feta cheese. 1 apple. Or: roasted vegetables including roasted butternut squash, with roast potatoes. Snacks: Grapes, 1 banana or a handful of nuts. Dinner: Whole wheat pasta with homemade tomato sauce, containing vegetables and beans. Or: 1 wholegrain wrap stuffed with mixed beans and grilled peppers, plus salad. Or: 2 slices of rye bread with 2 scrambled eggs. 25 g of dark chocolate for dessert.

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Diet example number 3: weight maintenance This 64 year old woman has maintained a BMI of 21.5 throughout her adulthood. Breakfast: 200ml unsweetened orange juice. 125g unsweetened fruit and nut muesli served with 200ml semi-skimmed organic milk. A cup of peppermint tea. Lunch: 100g Puy lentils, cooked with 2 cloves of garlic in vegetable stock. 250g mixed vegetables (e.g. mushrooms, celery, fennel, broccoli, onion) stir-fried in half a tablespoon of olive oil and served with a handful of roasted pumpkin seeds. 1 medium-sized baked potato. Half a grapefruit, served with 1 tablespoon of fat-free plain yoghurt, a teaspoon of honey, and a handful of Co-Op or Jordans oat crunchies. Dinner: Large bowl of home-made vegetable soup. 2 slices of organic wholemeal or superseeded bread, toasted; scrape of butter added. 1 apple and 50g of hard cheese (e.g. Wensleydale). Snacks: A handful of dried apricots and a handful of nuts. A couple of bite-sized chocolate brownies (Co-Op) as a treat.

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Diet example number 4: weight-loss This 41 year old woman has recently lost 9 kg in 10 weeks, achieving a BMI of 19.5: Breakfast: 1 large handful of mixed nuts 1 banana. Or: 400 g of plain organic soya yogurt 1 grapefruit. Lunch: 2 slices of rye bread with peanut butter or avocado or organic cheddar cheese, tahini, and homemade coleslaw (cabbage, carrot, spring onion and egg-free mayonnaise). Or: Barbequeue vegetable stew: soya mince (TVP) with El Paso smoky BBQ fajita seasoning, 1 tin of tomatoes, kidney beans, and mixed vegetables e.g. onion, carrots, broccoli, courgettes, aubergines, and potatoes. Dinner: Quinoa korma: quinoa, Sainsbury’s “free from” korma sauce, and vegetables e.g. onions, green beans, and cauliflower. Grapes for dessert. Snacks: 1 or 2 biscuits

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18. FURTHER READING In terms of further reading, full references are listed in the references section at the end. I would also recommend the following resources: The China Study by Professor Colin T Campbell, 2006, Ben Bella Books Food, Nutrition, Physical Activity, and the Prevention of Cancer: a Global Perspective by the World Cancer Research Fund and the American Institute for Cancer Research http://www.dietandcancerreport.org/ Programme for Reversing Heart Disease, 1996, Ballantyne Books and Eat More, Weigh Less, 2001, Quill by Dr Dean Ornish www.diseaseproof.com which documents the latest research on nutrition and health, collated by Dr Joel Fuhrman Eat to Live by Dr Joel Fuhrman, 2011, Little Brown and Company Prevent and Reverse Heart Disease by Dr Caldwell B Esselstyn, 2007, New York, New York: Avery, Penguin Group White Lies by Dr Justine Butler http://www.vegetarian.org.uk/campaigns/whitelies/whiteliesreport.pdf Your Life in Your Hands by Professor Jane Plant, 2007, Virgin Books The Soya Story by Dr Justine Butler (available to download from http://safteyofsoya.com/) Other extensive references are available on http://safetyofsoya.com/resources/soyaresearch.php) The Healthiest Diet of All: http://www.viva.org.uk/guides/healthiestdietofall.htm

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REFERENCES Abrams SA, Griffin IJ, Hawthorne KM et al. 2005. A combination of prebiotic short-and long-chain inulintype fructans enhances calcium absorption and bone mineralisation in young adolescents. Am J Clin Nutr 82;2:471-6 Abubakar I, Myhill DJ, Hart AR et al. 2007. A case-control study of drinking water and dairy products in Crohnâ&#x20AC;&#x2122;s disease â&#x20AC;&#x201C; further investigation of the possible role of Myocabacterium avium paratuberculosis. Am J Epidemiol 165;7:776-83 ACS 2011. American Cancer Society Guidelines on Nutrition and Physical Activity for Cancer Prevention http://www.cancer.org/acs/groups/cid/documents/webcontent/002577-pdf.pdf accessed 29.2.12 Adeghate E, Schattner P, Dunn E 2006. An update on the etiology and epidemiology of diabetes mellitus. Annals of the New York Academy of Sciences 1084:1-29 Agatston A 2003. The South Beach Diet p243-57. Headline Book Publishing Akhter M, Inoue M, Kurahashi N et al. 2008. Dietary soy an isoflavone intake and risk of colorectal cancer in Japan public health center-based prospective study. Cancer Epidemiol Biomarkers Prev 17:2128-2135 Alavanja MCR, Field RW, Sinha R et al. 2001. Lung cancer risk and red meat consumption among Iowa women. Lung Cancer 34;1:37-46 Albert MJ, Mathan VI, Baker SJ 1980. Vitamin B12 synthesis by human small intestinal bacteria. Nature 283;5749:781-2 Allen NE, Appleby PN, Davey GK et al. 2002. The associations of diet with serum insulin-like growth factor 1 and its main binding proteins in 292 women meat-eaters, vegetarians, and vegans. Cancer Epidemiol Biomarkers Prev 11:1441-1448 Allen NE, Appleby PN, Davey GK et al. 2000. Hormones and diet: low insulin-like growth factor-1 but normal bioavailable androgens in vegan men. British Journal of Cancer 83(1):95-7 Allen NE, TJ Key, Appleby PN et al. 2008. Animal foods, protein, calcium and prostate cancer risk: the European Prospective Investigation into Cancer and Nutrition. Br J Cancer 98;9:1574-1582 Almario RU, Vonghavaravat V, Wong R et al. 2001. Effects of walnut consumption on plasma fatty acids and lipoproteins in combined hyperlipidaemia. Am J Clin Nutr 74:72-79 Amanzadeh J, Gitomer WL, Zerwekh JE et al. 2003. Effect of high protein diet on stone-forming propensity and bone loss in rats. Kidney International 64:2142-2149 Ambroszkiewicz J, Klemarczyk W, Chelchowska M et al. 2006. Serum homocysteine, folate and vitamin B12 and total antioxidant status in vegetarian children. Adv Med Sci 51:265-8 American Diabetes Association 2010. American Diabetes Association: Standards of medical care in diabetes -2010. Diabetes Care 33 (Suppl 1) S11-S61 American Dietetic Association Report 2003 Position of the American Dietetic Association and Dieticians of Canada: Vegetarian diets.103;6:748-765

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American Heart Association 2012. High-protein diets http://www.heart.org/HEARTORG/Get-

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