DIETING AND MECHANISMS OF WEIGHT LOSS 3 Groups – One Consistent Finding
95% of all dieters regain their lost weight within one to five years Several long-term follow-up studies have shown that the success rate of diets, over time, is dismal at best. It is estimated that 95% of diets simply don’t work over the long term Studies have shown that 90-95% of individuals who diet are unsuccessful in the long term
Why don’t diets work?
They focus on short term results (vs long term, permanent weight loss) They focus on reducing calories as the priority (often at the expense of good nutritional principles) They often change the ratio of fat to muscle mass negatively (which leads to further weight gain)
Mechanism of weight loss
Quite simply, to lose weight a person needs to consume less calories than they use OR use more calories than they consume Diet programs focus on reducing calories consumed Exercise programs focus on increasing calories used Diet and exercise combined will obviously provide the quickest weight loss results
METABOLISM Metabolism and Metabolic rate
Metabolism o The chemical processes occurring within a living cell or organism that are necessary for the maintenance of life Metabolic Rate o The rate at which your body burns calories performing normal everyday activities (neither gaining weight nor losing weight)
TDEE and BMR
Total Daily Energy Expenditure (TDEE) o 70% calories required for BMR o 15% calories required for exercise o 15% calories required for food digestion Basal Metabolic rate (BMR) o Minimum calorific requirement needed to sustain life in a resting individual o BMR responsible for approximately 70% of all calories burned in a single day
BMR and Calories
BMR is the minimum calorific requirement to sustain life in a resting individual
Therefore anything that slows down or speeds up your BMR has a large affect on how many calories you are able to consume
The effects of exercise on BMR Resistance training and BMR
Resting lean muscle mass accounts for 80% of BMR
Therefore increasing a person’s lean muscle mass (through high intensity resistance training) would increase their BMR
CV training and BMR
Aerobic fitness contributes towards BMR
Therefore increasing a person’s level of fitness (through high intensity CV training) would increase their BMR
BMR IN RESPONSE TO EXERCISE
CH O
Lower intensity, long duration activity
FA T
Rest
60 mins
GOING EASY Calories burned during 60 minutes exercise, some but limited calorie burning afterwards. 150 calories CHO / 150 calories fats No real change in fitness and therefore resting metabolism.
CHO
High intensity, short duration activity
F A T
Rest
30 mins
GOING HARD Benefits of interval training Calories burned during 30 minutes exercise, much more calorie burning afterwards. 350 calories CHO / 150 calories fats Increase in fitness and therefore resting metabolism.
1. Lower intensity activity burns slightly more fat calories than high intensity 2. Metabolic rate remains elevated for some time after both activities (thereby continuing to burn CHO and fat calories at a greater rate when at rest) 3. Metabolic rate remains elevated longer after high intensity activity 4. High intensity activity brings about permanent increase in BMR
BECOME A FAT BURNING MACHINE
3km running
Unfit Individual 100% 90% 80% 70% 60% 50% 40% 30% 20% 10% 0%
CHO Fat
Easy (35mins)
GO EASY
Hard (20mins)
GO HARD
1. Total calories burned = 300 2. Fat 40% and CHO 60% 3. 120 calories of fat burnt
1. Total calories burned = 300 2. Fat 25% and CHO 75% 3. 75 calories of fat burnt
Fit Individual 100% 90% 80%
3km running
70% 60% 50%
CHO
40%
Fat
30% 20% 10% 0% Easy (35mins)
FAT BURNING MACHINE 1. Total calories burned = 500 2. Fat 35% and CHO 65% 3. 175 calories of fat burnt
Hard (20mins)
SUMMARY – Factors affecting BMR
Factors affecting BMR are: o Lean muscle mass o CV fitness These are brought about through: o Resistance training o High intensity CV training The result is a permanent increase in BMR o As long as fitness levels are maintained
SUMMARY – Factors affecting weight loss
Factors affecting fat loss are: o Structured bouts of activity These are brought about through o Long duration CV training o Frequent bouts of Activities of Daily Living (ADL) These activities do not bring about any permanent changes in BMR
UNDERSTANDING METABOLISM Biggest component of energy expenditure
Other components of energy expenditure
Permanent change in BMR
Fat loss but no change in BMR
NUTRITION AND WEIGHT LOSS Energy Intake
If successful weight loss is about energy balance it is equally important to consider energy intake The only nutrients that contain energy are carbohydrates, fats and protein (these are called macro-nutrients). Alcohol contains energy but is not a nutrient!
The role of fats in fat loss
When someone goes on a diet (minimising fat intake) the body holds onto its fat stores in response Thus someone on a low fat diet may lose weight but it is likely to be muscle not fat Fat (good fats) must be consumed to lose fat Some low fat products have additional and high levels of sugar causing insulin release
Common nutrition problems Most people present in one or two categories: 1. They consume too much fat and processed foods 2. They consume a low fat diet but one high in carbohydrates
So what should we do?
Minimise fat intake Mediate carbohydrate ingestion Or both You should also ensure protein intake is optimal: o Maximises recovery o Helps you feel full o Will not be stored as fat*
*When consumed in slightly higher quantities than normal for a relatively short period
Nutrition for fat loss
MACRONUTRIENTS CHO
PROTEIN
Glucose
Amino Acids
FAT
ALCOHOL
Fatty Acids
BLOOD
MUSCLE (metabolically active)
CHO storage Tank 0.5 kg max (Liver 0.1 kg)
GLUCAGON
INSULIN
Good (Unsat/ Essential fats)
Bad (Saturated)
FAT STORES
MICRONUTRIENTS VITAMINS & MINERALS
WATER
1. Excessive Carbohydrate (CHO) consumption can exceed storage limit and therefore store as fat. 2. Insulin resistance means more insulin and less glucagon to facilitate fat metabolism. 3. We become a carbohydrate burning machine. 4. To assist with weight loss we need to become a fat burning machine. 5. Consuming enough ‘good fats’ (we need to eat fat to lose fat), reducing CHO intake (reducing insulin) and ensuring enough protein (doesn’t store as fat) is present shifts the emphasis towards fat burning. 6. A multivitamin and range of multivitamin rich foods supports the process. 7. Stay hydrated as activity levels will change water requirements.
Glucose
Gives a body energy, helps with self-repair and growth, and performs cellular tasks Delivered to the muscle by insulin Muscle is like a ‘fuel tank’ When it is full, excess glucose (glycogen) goes to our fat stores instead of muscles
Amino Acids
The building blocks of proteins and essential to nearly every bodily function. Every chemical reaction that takes place in your body depends on them Delivered to the muscle by insulin Body takes what it needs and gets rid of the rest
Fatty Acids
Produced when fats are broken down. Can be used for energy by most types of cells. They also move oxygen through the blood stream and aid cell membrane development, strength and function Goes straight to fat stores Must have good fats in diet to burn fat Used for energy when muscle glucose levels are low
Insulin
Release in the response to the presence of glucose in the blood Needed to transport glucose and amino acids into the muscle Distributed in excessive amounts to reduce excessively abnormal blood sugar (high carbohydrate diet) High levels of insulin may contribute to our fatness Cells can become resistant to insulin turning our bodies into carbohydrate burning machines
Glucagon
Works with insulin to control blood sugar Mobilises stored energy (either glycogen or fats) into the bloodstream available for use Glucagon required to burn fat (fat burning friend) High levels of insulin limit glucagon Monitor carbohydrate levels in diet in order to promote fat burning
Micronutrients
Ensure system operates at maximum efficiency
Alcohol
Goes straight to the muscle Used in preference to glucose in the bloodstream and glycogen and fat stores Food eaten while consuming alcohol is diverted to fat stores
GUIDELINES FOR DAILY INTAKE CHO Never less than 100g per day (increase as need - body type, activity, le an mass) Vitamins & Minerals
FAT
if in doubt refer to GP. If low than consider multivitamins and minerals
20-40g (not more than 30% of daily intake)
PROTEIN
0.7-2.0g per kg of body weight
Energy Balance OUT Metabolism CV Fitness Active Muscle Mass Active Daily Living (ADL) CV Exercise
IN Carbohydrates 1g = 4 calories Fat 1g = 9 calories Protein 1g = 4 calories Alcohol 1g = 7 calories
HORMONES
Insulin
Serotonin
Cortisol
Leptin
Thyroid
Glucagon

Insulin: o o o o o

Released in the presence of glucose in the blood Needed to transport glucose and amino acids into the muscle Distributed in excessive amounts to reduce abnormally high blood sugar (high carbohydrate diet) High levels of insulin may contribute towards our fatness Cells can become resistant to insulin turning our bodies into carbohydrate burning machines
Glucagon: o Works with insulin to control blood sugar o Mobilises stored energy (either glycogen or fats) into the bloodstream available for use o Glucagon required to burn fat (fat burning friend) o High levels of insulin limit glucagon o Monitor carbohydrate levels in diet in order to promote fat burning
Cortisol o Stress hormone o High insulin increases secretion o High cortisol associated with a drop in testosterone and Human Growth Hormone (HGH) o Also activates fat cells to store fat
Leptin o Tells the body when to eat and when we are satisfied o Produced by body fat o Some people can develop resistance to leptin causing an increased desire to keep eating and/or cravings
Serotonin o Signals satisfaction o Low levels cause depressions, obesity and lethargy o Also can cause a preference for refined carbohydrates and overeating because the brain senses it is starving o Protein restrictive diets cause serotonin levels to plummet Thyroid o Regulates the metabolism o Low thyroid (hyperthyroidism) affects approximately 30% of the population o Low thyroid reduces our fat burning rate and inhibits energy levels
Hormones in Summary
Excessive production of Insulin is a problem o Caused by high carbohydrate consumption – particularly high GI Testoserone and HGH produced during resistance training maximise fat loss Resistance training helps to tip our hormone balance in favour of weight loss Regular exercise also reduces stress thereby keeping Cortisol at bay and improving Serotonin levels
A TALE OF TWO TWINS Both weigh 90kg and are 40% body fat
TWIN A DECIDES TO LOSE WEIGHT ON A DIET
TWIN B CHOOSES EXERCISE AND DIET
After 10 weeks both lose weight
TWIN A LOSES 20KG PAYING FOR PRE-PACKAGED MEALS
TWIN B IS FRUSTRATED SHE HAS ONLY LOST 10KG
NOW 70KG JUST 10 WEEKS LATER
NOW 80 KG IN 10 WEEKS
After 10 weeks both change body composition
TWIN A IS NOW 35% BODY FAT
TWIN B IS NOW 30% BODY FAT
40% OF 90KG = 36KG FAT
40% OF 90KG =36KG FAT
35% OF 70KG = 24.5KG FAT
30% OF 80KG = 24KG FAT
<11.5KG FAT
<12KG FAT
Results are very different BACK TO NORMAL
REDUCED EXERCISE
LOST 20KG FAT BUT ONLY 11.5KG FAT
LOST 10KG OF WEIGHT AND 12 KG FAT
LOST 8.5KG OF MUSCLE / LEAN BODY MASS
GAINED 2KG LEAN / MUSCLE >METABOLISM
<METABOLISM
10 WEEKS LATER BACK TO 90KG BUT WITH 8.5KG LESS LEAN MUSCLE MASS 8.5KG FATTER
DOWN TO 70KG AND INCREASED METABOLISM (INCREASED FAT LOSS) LEANER