Klesges et al found that 89% of the female population restrain their food intake at some point in their lives. But in their restraint theory Herman and Mack suggest that this restraint can actually lead to an increase in overeating.
The Boundary Model – To try and explain why restraint might increase eating Herman and Polivy developed their boundary model. This model says that ‘hunger’ ensures we don’t eat less than the minimum level, whilst ‘satiety’ ensures we don’t eat more than the maximum level. Herman and Polivy said that dieters have a greater range between hunger and satiety and require more food to reach this level of satiety. These dieters often have their own self-imposed “diet boundary” which they try not to eat more than. However, when they breach this boundary they tend to eat until they are full (which as we know takes longer for dieters than non-dieters). This is known as the “what the hell” phenomenon whereby the dieter feels they might as well eat lots as they have gone past their boundary anyway.
The Role of Denial
Wegner et al (1987) found that when participants were asked to not think of a white bear they actually thought about it quicker. This illustrates how denial and trying not to do something can make it a more prominent thought. Dieters will try not to think about eating unhealthy food, however this means it plays on their mind more and becomes more appealing. Wegner called this the “theory of ironic processes of mental control”, and he said it can explain why dieting rarely works.