Dieting is increasingly popular as people try to fit into the thin western ideal of beauty. Theories for the failure of dieting include the restraint theory, while it has been suggested that the key to success is the amount of attention we give to the detail of our food.
The restraint theory (Herman and Mack) suggests that restraining our food intake actually increases the risk of overeating, which is why many diets fail and some people even end up putting more weight on. Herman and Polivy (1984) developed the boundary model to explain this. According to this model, dieters have a larger range between their hunger and satiety levels, so it takes them longer to feel hungry and they need to eat more food to be satisfied. Dieters also have a self imposed desirable level of food intake. When they perceive themselves to have gone beyond this level, they experience the disinhibition effect and continue to eat until satisfied. They are more likely to perceive themselves as going over this level if it is something ‘forbidden’ (e.g. cake).
This theory is supported by a study by Herman and Mack (1975). They had restrained and non-restrained women of normal weight eat zero, one or two milkshakes. The participants were then allowed to eat as much ice cream as they wanted. For non-restrained eaters, the results were as expected; those more ate more milkshake, ate less ice cream, as they were closer to their satiety level. For restrained eaters however, those who ate more milkshake ate more ice cream; this is the disinhibition effect. This shows that a food preload (e.g. milkshake) often results in overeating for those restraining their food intake. However, this study is gender biased as it only involves women. The results can therefore not be generalised to both genders. This study also ignores individual differences (e.g. some women may just enjoy ice cream more than others) so the