DIET TRENDS
POPULAR LIQUID DIETS Liquid diets can be essential for certain medical purposes. However, when liquid diets are used for general weight loss, they can be unbalanced or harmful. This article will focus on the nutritional content and evidence related to five popular liquid diets.
Maeve Hanan UK Registered Dietitian Freelance Maeve is a Consultant Dietitian and Health Writer. She also runs the blog Dietetically Speaking.com, which promotes evidence-based nutrition and fights nutritional nonsense.
REFERENCES Please visit: https://www. nhdmag.com/ references.html
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Liquid diets and meal replacements come in various forms. There are some medical indications for liquid diets, such as before or after certain types of surgery, or the use of exclusive enteral nutrition for inducing remission in Crohn’s disease. However, many liquid diets that are promoted as magic bullet solutions for weight loss, are extreme and can be nutritionally harmful. JUICE DIETS
Juice diets involve only consuming juiced fruit and vegetables for about 3-10 days. These diets are often promoted as ‘detoxes’, ‘cleanses’ or ‘juice fasts’. But, of course, no diet can ‘detoxify’ our body, as this is done by our lungs, gut, skin and kidneys. A popular type of juice diet is called ‘the master cleanse’ or the ‘lemoncayenne pepper diet’. This extreme diet involves consuming mainly lemon juice, cayenne pepper, maple syrup and water for 10 days. Raw juice diets are also popular, some of these involve consuming up to two litres of raw fruit and vegetable juice per day! Because juice diets are very low in calories, they can lead to weight loss, although weight tends to be regained when normal eating is resumed.1 Juice diets also tend to be deficient in calories, protein, fat, iron, calcium, vitamin B12, iodine and selenium. Juice ‘cleanses’ can lead to unpleasant side effects, including: bloating, cramping, diarrhoea, dizziness, low energy levels and erratic blood sugar levels. There are also health risks related to juice fasting, which is especially unsuitable for those who are nutritionally
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vulnerable, such as children, pregnant or breastfeeding women, those who are malnourished, or those who have a history of an eating disorder. A high intake of juice may interact with certain medications (such as warfarin). It can also be harmful to undertake a diet like this for those with diabetes, liver disease, kidney disease and thyroid issues (due to high levels of goitrogens found in plant foods). THE CABBAGE SOUP DIET
This fad diet has re-emerged many times over the years and was very popular in the 1980s. This diet involves consuming mainly (you guessed it) cabbage soup for around a week. Some fruit and vegetables or low-fat milk are also allowed on this diet. No studies have investigated the impact of the cabbage soup diet. However, the impact is likely to be very similar to juice diets, as this is very low in calories and provides little to no protein or fat. Therefore, it is another extreme and unbalanced approach, with the likelihood of gut irritation from the high intake of cabbage. WATER FASTING
This usually involves only consuming water for 24 to 72 hours, although black tea and coffee are also sometimes allowed. Water fasting for 24 hours may have similar health benefits to other types of daily intermittent fasting, such as improving metabolic health and reducing inflammation in the body.2 It has been suggested that this may be related to the ‘thrifty genotype theory’