Monday, March 24, 2008


It is often assumed that diets do not work because the dieters are not actually dieting. The dieting industry tells us that failed dieters are weak-willed and are simply not sticking to their diet. The responsibility for not losing weight is placed firmly on the dieter's shoulders with no understanding of the processes which constitute diet-breaking.

Experimental work shows that dieters overeat both in the laboratory and in naturalistic studies. Perhaps this behaviour is an illustration of diet-breaking, suggesting that not sticking to a diet is a far more complex issue than simply a lack of determination.

So why do dieters not stick to their diets? Surely all they have to do is eat less food?

Anyone who has ever dieted can provide you with reams of reasons why they break their diets, and will cite hundreds of examples of times when they have eaten more than they intended. Dieters may recall the different causes for their episodes of 'over-indulgence' and yet most dieters still blame themselves, and regard themselves as failures.

I want to draw upon the results of an experiment that I carried out as part of my work for my PhD, which suggests that diet-breaking is not the fault of the dieter, it does not reflect personal inadequacy, but is an inevitable consequence of the structure of dieting. Overeating is part and parcel of attempting to diet and is a consequence of trying to eat less, a direct product of dieting.

Diet Start

I carried out a study in the final year of my PhD which examined the effects of dieting and attempted to find out why so many diets fail and why women break their diets. The overeating behaviour shown by dieters in the laboratory is also reported by dieters in their day-to-day lives. Many women report fluctuating between days when they manage to eat less and days when they completely overeat.

Imagine sticking to 1000 calories a day for three days and then being invited out to dinner on the fourth day. Tempted by all the food available and the fact it is a special occasion, many dieterssay that they would eat more at the dinner than if they hadn't been trying to diet on the previous days. It is like thinking 'Oh what the hell. If I'm going to break my diet I might as well make the most of it.' It is similar to trying to give up smoking or drinking.

A friend of mine used to smoke only after six in the evening. She would never think about a cigarette before this and certainly wouldn't think of smoking first thing in the morning. At New Year she decided to stop smoking. From the moment she decided to stop all she could think about was cigarettes, even in the morning. She woke up desperate to smoke and found that when she actually had one cigarette, for the first few days of smoking again, she smoked more than ever before. The overeating found in dieters is similar to this.

It was originally believed that overeating was followed by a period of dieting, that people dieted because they had a tendency to overeat, and needed to compensate for episodes of indulgence. Dieters are all sorts of people. Some have problems with food, but the vast majority of dieters simply see themselves as being larger than society tells them to be. There is no evidence to suggest that dieters become dieters because they have episodes of overeating.

It was then proposed that dieting caused overeating — a complete reversal of the original theory. Researchers suggested that the overeating shown by dieters in the laboratory and reported in their day-to-day lives was a direct consequence of attempting to eat less. This is similar to the analogy with smoking; trying to stop smoking causes a desire to smoke more and trying to stop eating causes overeating. The difference is that stopping smoking is good for you, stopping eating isn't!

This idea was called the causal analysis of eating behaviour and suggests that attempting not to eat, paradoxically, increases the probability of overeating, the specific behaviour dieters are attempting to avoid. It represented a new approach to the eating behaviour of dieters and is an interesting reappraisal of the situation.

A study by Wardle and Beales in 1988 showed that dieters tended to overeat and the authors concluded that the results 'supported the idea that dieting causes disturbances of food intake'.

So why does this happen? Why does dieting cause overeating?

It is possible that overeating is a direct product of changes which occur as a result of dieting. Dieting could cause changes which increase the tendency to eat more.

It has been predicted from the causal analysis of dieting and overeating that increasing dieting would cause an increase in those factors related to overeating. Research suggests that changes in mood, state of mind, control and hunger occur as a consequence of dieting and could cause an increase in eating.

A classic study was carried out in 1950 by an American professor called Ancel Keys and his colleagues. Their aim was to evaluate the effects of a period of restricting calories, and to see whether reducing food intake caused overeating. Over a period of twelve weeks, thirty-six healthy non-dieting men received a carefully controlled daily food intake of approximately half their normal intake and consequently lost 25 per cent of their original body weight. Ancel Keys states that they developed a preoccupation with food, often resulting in their hoarding or stealing it. They showed an inability to concentrate, with mood changes such as depression and apathy being common. At the end of the period of dieting the men were allowed to eat freely and often ate continuously. They reported loss of control over their eating behaviour, sometimes resulting in binge eating. The author concluded that these psychological effects were not a function of the actual process of starvation, but were more likely to be due to the restriction of their diet.

In 1988, Warren and Cooper, in a study in Cambridge assessing the effects of dieting on both mood and the control of eating, placed seven men and seven women on a calorie- restricted diet for two weeks, and monitored any daily changes. They found an increase in feelings of loss of control, over eating and increased preoccupation with food.

Dieting seems to cause overeating by changing factors which contribute to eating more. The study which I carried out attempted to assess what these factors could be.

Up to 90 per cent of the female population diet at some time in their lives. The aim of the study was to examine the effects of these constant attempts at losing weight and to analyse their contribution to overeating. The failure to lose weight is often regarded as a sign of weakness and an indication that the dieter is not dieting properly. The following results suggest that failed dieters are simply responding to changes which occur during a diet and that breaking your diet is inevitable.

... andjoyohoxing