As many as 1 in 4 of us are on a weight reduction diet plan at any one time. While diets may be effective at shifting weight in the short term, they don’t work in the long run and cause untold mental and physical damage to the people doing them.
Fad diets promise quick weight loss – they do not offer a healthy, long-term weight control solution.
If fad diet plans did work there wouldn’t be a diet industry which is estimated to be worth over £1bn in the UK - it would put itself out of business! But the diet industry relies on a recidivism rate of approximately 95%, so for everyone 100 people on them, 95 will eventually return.
Fad diets work by restricting our total calorie intake. When calories are limited weight loss does occur. However, by their very nature the rate of weight loss associated with diet plans can be rapid, unsafe and unsustainable. Because diet plans are so regimented they are often only adopted in the short term, so in most cases when someone stops following the diet the weight that is lost is regained, and more often than not, more weight is regained than was lost in the first place.
As a result dieting can become an addictive, unfulfilling and an ineffective way of losing weight. And it can lead to a pattern of behaviour known as yo-yo dieting.
Yo-yo dieting describes the cyclical behaviour of negative feelings of one's body shape and a strong desire to improve one's shape, which can lead to restrictive eating habits - very low calorie dieting. Prolonged food restriction can rarely be sustained with an abundance of food available and especially if we feel we are not allowing ourselves the food we want to eat. This often leads to loss of control, binge eating, returning to normal eating patterns and further weight gain. The cycle then continues if we continue to have negative feelings about our body shape. Research indicates that weight gain occurs more quickly with each successive bout of dieting.
There are a range of diet plans and programmes available on the market today.
Starvation diets or very low calorie diets rely on cutting the total calories we need to approximately 1000kcal. This might seem like the best way to lose weight but starvation or very low calorie dieting slows your body’s metabolism (the rate at which we burn calories) by as much as 40% which can make it progressively more difficult to lose weight and keep it off. The body goes into starvation mode and adapts to the reduced calorie intake by becoming very efficient at making the most of the calories it does get from food.
Technically the body will lose body fat, but it will also lose lean muscle mass.
Because of the very low calorie intake the body will use some body fat as energy (ketosis) and lean tissue or muscle (gluconeogensis) to provide it with the calories it needs to function. This process known as catabolism causes muscle mass to drop. Given that muscle burns calories, the less muscle a person has the fewer calories they require.
In addition to the loss of water and muscle, low calorie diets deprive the body of essential vitamins and nutrients needed to keep it healthy. The initial weight that is lost is primarily muscle and water and is quickly regained when the old eating habits return.
Low carbohydrate diets increased in popularity in the early 2000s with the rediscovery of the Atkins diet as an effective way of losing weight. Low carbohydrate diets are based on the premise that a diet very low in carbohydrate leads to a reduction in the body’s insulin production, resulting in fat and protein (muscle) stores being used as the body’s main energy source.
The ultimate aim of low carbohydrate diets is to force the body to use fat as its main energy source. When this happens a person produces ketones (a by product which is generated when fatty acids are broken down for energy) to fuel parts of the body that cannot use fat as an energy source. During this period a person is said to be in a state of ketosis which is characterised by smelly breath and side-effects such as nausea and fatigue.
While people who go on low carbohydrate diets do lose weight and do so quickly this comes at a price. The majority of weight that is lost comes from loss of water and muscle tissue. As with very low calorie diets this loss of muscle (metabolically active tissue) will lead to a reduction in the number of calories a person needs to maintain their weight.
Followers of low carbohydrate diets also miss out on essential nutrients and vitamins which come from fruit, vegetables and grains. Ketosis can also cause kidney damage in individuals with already established kidney problems.
People on low carbohydrate diets often increase their intake of protein or fat which can lead to other issues. For example, high levels of protein may put an increased strain on the kidneys, risk dehydration and can cause the body to lose calcium, leading to osteoporosis. Higher intake of fat, particularly saturated fat can increase the risk of heart disease in those who follow these diets in the longer term.
At the heart of formula diets are meal replacement products which usually come in the form of milkshakes, soups, snacks or ready meals. Most are made from sugar and milk and contain a bulking agent (e.g. plant fibre or gum). By law meal replacement products must provide the recommended amount of nutrients required for good health (providing at least 25% protein and 23 vitamins and minerals). When used properly meal replacement diets can be effective as they provide fewer calories than the person requires to maintain their body weight. However meal replacement diets do not teach people how to make healthy food choices.
The food choices available to people who use meal replacements are more limited and this lack of variety may cause them to stop using them after a short period of time. While meal replacements are nutritionally balanced, there is also evidence to suggest that our bodies are better able to make use of the vitamins and minerals found in food rather than those found in fortified foods. There are also few large-scale, long term trials testing the efficacy of meal replacements in “real life” situations.
In recent years detoxification or “detox” diets have become popular, particularly with celebrities. Also known as cleansing diets such programmes claim to cleanse the body of built up toxins from the environment that may be causing weight gain, an inability to lose weight or various illnesses. Certain foods are avoided while on a detox diet including sugar, dairy products, wheat, and coffee.
While weight loss may occur during a cleansing diet, as with most other calorie restriction diets the majority of weight lost will be water and some muscle. There are also a number of harmful side effects. Loss of fluid can lead to dehydration, fatigue, mood swings, irritability and electrolyte imbalance, which can in extreme cases lead to cardiac arrest.
Supplements and laxatives which are also used during detox diets may also lead to health problems, including mineral and electrolyte imbalances and problems with the digestive system.
There is no scientific evidence to support the efficacy of detox diets. The body is more than capable of removing toxins itself through the proper functioning of the liver and kidneys particularly if a person follows a balanced diet. So in most cases apart from potentially damaging your health detox diets and the products which accompany them can be considered a waste of money.