(2026 Exams) Psychological Explanations

Q: Psychological Explanations for Obesity

Herman and Polivy (1975) proposed restraint theory. The theory posits that the more an individual tries to restrain themselves from eating, the more they eat. The boundary model explains this phenomenon.

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Psychological Explanations for Obesity

Herman and Polivy (1975) proposed restraint theory. The theory posits that the more an individual tries to restrain themselves from eating, the more they eat. The boundary model explains this phenomenon.

Restraint

Restraint refers to an individual’s conscious effort to not consume food to avoid gaining weight or promote losing weight.

Restraint theory

When people try to restrain themselves from eating too much, they implement a cognitive diet boundary.
These eaters will eat until the cognitive boundary is reached, where they will then stop.
But as they are still hungry, they will often eat beyond the boundary. Once this happens, they enter into a state of disinhibition.

The boundary model

The boundary model posits that there is a biological continuum with hunger at the minimum and satiety at the maximum.
Food intake is triggered when the minimum level is reached, hunger, and stops when the maximum level is reach, satiety.
This process means that we always consume the minimum amount needed and so stay healthy.
But many psychological, environmental and social factors can impact the size of the range, and so individuals can develop unhealthy eating behaviours.

Disinhibition

If an individual who is trying to restrict their eating goes over their cognitive limit and enters disinhibition, they proceed to ‘give-up’ on their restriction and binge eat.
This comes from the idea that if they have already broken their cognitive barrier, they may as well break it completely and eat until they are full, or beyond.
This disinhibition may be triggered by specific emotional or situational factors, or just by habitual behaviours.

Cognitive control

When food becomes a consuming part of our cognitive life, we can end up ignoring physiological markers of hunger and satiety and instead try to control our food intake consciously.
Cognitive factors tend to control restrained eaters, while physiological factors control normal eaters.

Explanations for the Success and Failure of Dieting

There are many factors that influence whether a person succeeds in losing weight when dieting.

Support

If family and friends are aware of attempts to diet and positively reinforce this behaviour, then dieting is more successful.
Eating is a very social occasion. So feeling supported can make sticking to a diet easier.
Joining support groups such as weight watchers can help to make weight loss a shared experience and maintain motivation.
But some people find constant external motivation a huge pressure and worry about disappointing their loved ones, so secretly binge eat.

Extreme dieting

People who attempt sudden and extreme calorie control end up with huge physiological changes. This is because their body tries to preserve fat stores. Starvation leads to a decrease in metabolic rate.
When returning to normal eating, these physiological changes often lead people to have a higher excess calorie intake than before the diet. So they put back on any weight they have lost very quickly.
This will cause the person to diet again and soon health problems can escalate.