Outline and evaluate psychological explanations for obesity
Obesity is estimated to affect 1 in 4 UK adults and costs an estimated £268 billion annually.
There are three main psychological explanations for obesity. Restraint Theory, developed by
Herman and Polivy (1975), explains obesity as a paradoxical outcome of dieting, where
attempts to restrict food intake often lead to increased preoccupation with food and
eventual overeating. Restrained eaters impose strict cognitive control over their eating,
categorizing foods as "good" or "bad" and setting rigid rules about what they can consume.
However, this control is counterproductive as it causes individuals to ignore physiological
hunger and satiety cues, making them more vulnerable to disinhibition—where a lapse in
restraint leads to excessive eating. Disinhibitors, such as mood, stress, media influences, and
food-related cues like smells and sights, trigger loss of control, resulting in binge eating. To
further explain this, the Boundary Model (Herman & Polivy, 1984) suggests that restrained
eaters have distorted physiological boundaries: a lower hunger boundary, making them less
responsive to hunger signals, and a higher satiety boundary, meaning they require more
food to feel full. Between these boundaries lies the zone of biological indifference, where
social and cognitive factors play a significant role in eating behaviour. Restrained eaters set
a cognitive diet boundary, but once they break it—by eating a "forbidden" food like
chocolate—the "What-the-Hell" effect takes over, leading them to overeat until they reach
their satiety boundary, which is higher than that of non-dieters. This cycle of restriction,
disinhibition, and binge eating explains why dieting often fails and can contribute to obesity.
Thus, excessive restraint in eating behaviours can be self-defeating, emphasizing the
importance of balanced eating rather than rigid dietary control. This cycle of restriction,
lapse, and binge eating encourages a pattern of overeating that is hard to control. Over time,
repeated episodes of binge eating and disrupted appetite regulation contribute to an
increased overall calorie intake, which can result in weight gain and the development of
obesity. Thus, psychological factors involved in rigid dieting can ironically promote
behaviours that lead to obesity rather than prevent it.
A strength of the restrained eating and disinhibition explanations are its supporting
evidence. Wardle and Beales (1988) randomly allocated 27 obese women to three groups;
diet group following a restrained eating diet, exercise group not following a restrained diet,
and a control group receiving no treatment. When food intake was assessed, it was found
restrained eaters ate significantly more, consuming more calories than the other groups.
This occurred due to disinhibition of their eating, which would cause bingeing. So evidencing
that a restrained diet causes overeating and thus weight gain and obesity. However, a study
by Savage et al (2009) found that restrained eating while dieting leads to weight loss as
opposed to weight gain, at least in the short term. Which is entirely opposite of the restraint
theory assumption. Despite this, there is still good evidence for disinhibition causing binge
eating behaviours and so evidence for restraint theory alongside this.
A weakness of theses explanations is that restraint theory is in fact more complex than the
boundary model indicates. Research by Westernhoefer (1991) has indicated two different
forms of restraint; rigid restraint which is an all or nothing approach to liming food intake
and flexible restraint which allows the restrained eater to eat limited amounts of some
forbidden food without triggering disinhibition. If only rigid restraint is likely to lead to
Obesity is estimated to affect 1 in 4 UK adults and costs an estimated £268 billion annually.
There are three main psychological explanations for obesity. Restraint Theory, developed by
Herman and Polivy (1975), explains obesity as a paradoxical outcome of dieting, where
attempts to restrict food intake often lead to increased preoccupation with food and
eventual overeating. Restrained eaters impose strict cognitive control over their eating,
categorizing foods as "good" or "bad" and setting rigid rules about what they can consume.
However, this control is counterproductive as it causes individuals to ignore physiological
hunger and satiety cues, making them more vulnerable to disinhibition—where a lapse in
restraint leads to excessive eating. Disinhibitors, such as mood, stress, media influences, and
food-related cues like smells and sights, trigger loss of control, resulting in binge eating. To
further explain this, the Boundary Model (Herman & Polivy, 1984) suggests that restrained
eaters have distorted physiological boundaries: a lower hunger boundary, making them less
responsive to hunger signals, and a higher satiety boundary, meaning they require more
food to feel full. Between these boundaries lies the zone of biological indifference, where
social and cognitive factors play a significant role in eating behaviour. Restrained eaters set
a cognitive diet boundary, but once they break it—by eating a "forbidden" food like
chocolate—the "What-the-Hell" effect takes over, leading them to overeat until they reach
their satiety boundary, which is higher than that of non-dieters. This cycle of restriction,
disinhibition, and binge eating explains why dieting often fails and can contribute to obesity.
Thus, excessive restraint in eating behaviours can be self-defeating, emphasizing the
importance of balanced eating rather than rigid dietary control. This cycle of restriction,
lapse, and binge eating encourages a pattern of overeating that is hard to control. Over time,
repeated episodes of binge eating and disrupted appetite regulation contribute to an
increased overall calorie intake, which can result in weight gain and the development of
obesity. Thus, psychological factors involved in rigid dieting can ironically promote
behaviours that lead to obesity rather than prevent it.
A strength of the restrained eating and disinhibition explanations are its supporting
evidence. Wardle and Beales (1988) randomly allocated 27 obese women to three groups;
diet group following a restrained eating diet, exercise group not following a restrained diet,
and a control group receiving no treatment. When food intake was assessed, it was found
restrained eaters ate significantly more, consuming more calories than the other groups.
This occurred due to disinhibition of their eating, which would cause bingeing. So evidencing
that a restrained diet causes overeating and thus weight gain and obesity. However, a study
by Savage et al (2009) found that restrained eating while dieting leads to weight loss as
opposed to weight gain, at least in the short term. Which is entirely opposite of the restraint
theory assumption. Despite this, there is still good evidence for disinhibition causing binge
eating behaviours and so evidence for restraint theory alongside this.
A weakness of theses explanations is that restraint theory is in fact more complex than the
boundary model indicates. Research by Westernhoefer (1991) has indicated two different
forms of restraint; rigid restraint which is an all or nothing approach to liming food intake
and flexible restraint which allows the restrained eater to eat limited amounts of some
forbidden food without triggering disinhibition. If only rigid restraint is likely to lead to
