Weight Loss Diets

Weight loss is a national obsession. Magazines, TV programs and books promising miraculous results from the latest fad diets are everywhere. However, many people who follow these diets are disappointed as they lose weight quickly only to regain it later. We analyse some of today’s most popular weight loss programmes.

High protein, low carbohydrate diets

High protein, low carbohydrate diets are currently receiving a considerable amount of media attention and are the cause of much controversy. The use of high protein, low carbohydrate diets is based on the following:

• Carbohydrates are converted to glucose in the body. Glucose, in turn, stimulates the production of the hormone insulin, which promotes fat storage
• Some people are resistant to insulin and so it accumulates in the blood steam. Restricting carbohydrates helps to decrease the amount of insulin secreted into the blood stream
• Protein has a neutral effect on weight gain because it does not stimulate insulin secretion
• Limiting your carbohydrate intake will lead to a process known as ketosis, where the body starts to burn fat for energy

Some of the most popular high protein, low carbohydrate diets include:

• The Atkins diet. In this diet, Dr. Atkins recommends that the diet consist of unrestricted amounts of protein foods, such as meat, poultry, fish, eggs and cheese. Fat is also allowed in large amounts. Carbohydrate foods, including pasta, rice and bread are limited, at first very severely, until the final phase of the diet, which allows no more than 40-60 grams of carbohydrate per day
• Carbohydrate addict’s lifespan programme. This diet is based on the assumption that certain people are addicted to fat-causing carbohydrate foods. The diet claims that eating two high protein, low carbohydrate meals a day can diminish cravings for carbohydrate foods. One meal per day (the 'reward meal') may contain carbohydrate foods, as long as it is balanced with protein-rich foods
• Sugar busters! This diet is based on the theory that sugar, not fat, is the main cause of excess weight gain as it results in the secretion of insulin, which encourages fat storage. This diet divides foods into low and high glycemic index (GI) foods, and advocates the avoidance of foods with a high GI such as unrefined, simple, carbohydrates like sweets, pastries, cakes, and table sugar, as these are more effective in stimulating insulin secretion
• The Zone diet. This diet proposes that each meal and snack should consist of 40 per cent carbohydrate, 30 per cent protein and 30 per cent fat (prudent dietary guidelines suggest an intake of 50-60 per cent carbohydrate, 15-20 per cent protein and 30 per cent fat). It is based on the presumption that most people are insulin-resistant and need to limit insulin secretion-causing carbohydrates

The problem with high protein, low carbohydrate diets

While there is undoubtedly some truth to what the authors of these diets are saying some of the facts are oversimplified.

• Restricting the intake of carbohydrates also means that you are restricting your intake of fibre and other essential nutrients. Severe carbohydrate restriction can therefore lead to nutrient deficiencies
• The weight loss that occurs on low carbohydrate diets is usually as a result of water loss, not fat loss
• Remember too, that people who follow any diet plan, whether it be bogus or sound, are probably eating better than they were before they started the diet, and are likely to lose some weight
• High protein diets also tend to be high in saturated fats and cholesterol, which increases the risk of heart disease and certain types of cancer
• A high protein diet causes the body to lose calcium, which can increase the risk of osteoporosis (loss of bone density)
• High protein diets also place stress on the kidneys and can cause permanent kidney damage
• It is true that glucose stimulates the secretion of insulin which promotes the storage of fat. However, if a high carbohydrate meal is also low in fat, insulin will have little fat to store. It is therefore not necessary to severely restrict carbohydrates if you are also restricting fat
• It is true that restricting high GI foods (refined foods) and replacing them with low GI foods (unrefined, whole-grain foods) can aid in weight loss. It is not necessary to restrict total carbohydrates, as long as you are eating the right ones
• Protein does have less of an effect on insulin secretion, however research has shown that high protein diets may actually lead to insulin resistance
• It is true that consuming less than 100g of carbohydrate per day leads to ketosis, a process in which fat is burned for fuel. Ketosis is not a benign process and can cause headaches, dizziness, fatigue, nausea and bad breath
• Most of the health claims put forward by the advocators of these diets are based on anecdotal evidence, for example: 'a patient of mine….', rather than sound scientific research
• These diets often fail to make room for individual needs and preferences and often leave little room for variety of intake

The grapefruit diet

This diet is based on the premise that grapefruit contains a special 'fat-burning' enzyme. In this diet, grapefruit becomes the staple food, which compromises variety of intake. Grapefruit is a good addition to any diet and it is a good source of vitamin C. Sadly, it does not contain a special fat-burning enzyme.

The cabbage soup diet

The one-week cabbage soup diet consists of soup made with cabbage, onions, green peppers, tomatoes, celery, onion soup mix and water. One each day, various additions of fruits, vegetables, potatoes and meat are made to the diet. This diet is not based on scientific evidence and most of the weight loss is attributable to the loss of water. The diet also causes bloating and nausea. However, cabbage and other vegetable soups are good additions to a healthy, balanced diet.

Eat Right for your Type diet

Dr. D’Adamo proposes that people should eat according to their blood type whether this is O, A, B or AB. There are different diets and lifestyle plans for each type. For example, type O’s should be predominantly meat eaters, wile type AB’s should be predominantly vegetarian. D’Adamo proposes that if you eat according to your blood type you will naturally reach your ideal weight, regardless of your caloric or fat intake.

D’Adamo claims that lectins (proteins) found in foods interact with antigens found in the body’s cells, causing the cells to 'agglutinate', or adhere to each other. Certain foods, the theory goes, tend to make cells 'clump' in one blood type but not another. According to D’Adamo, lectins are responsible for a whole host of problems. However, the diet is based mostly on theories and case studies from doctors medical practices rather than on actual scientific data.

Food combining diets

These diets, such as Fit For Life and The Natural Way, advocate that concentrated proteins and concentrated carbohydrates should not be eaten together at the same meal. They suggest that because proteins and carbohydrates require different pH levels to activate their respective digestive enzymes that digestion is impaired if they are combined.

There may be some truth in the food combining theory but in most cases the body is extremely efficient at digesting a mixed meal. Also, proteins and carbohydrates occur together naturally in many foods, for example beans and lentils, some vegetables, potatoes and cereals, and are usually digested with little trouble.

The final verdict?

While many of the so-called fad-diets are based on some useful dietary principles, they are also based on simplified explanations only and often fail to take into account other factors.

What, then, is the best way to lose weight effectively? The answer is to exercise and follow a diet high in complex, high fibre, carbohydrates; low in fat and moderate in protein, which complies with the dietary principles of variety, moderation and balance.