AP® Psychology · Unit 5 · Topic 5.4

Feeding and Eating Disorders

Anorexia nervosa involves severe food restriction and significantly low body weight, often with a distorted body image; bulimia nervosa involves cycles of bingeing and compensating, usually at a near-typical weight.

Anorexia nervosa centers on restriction. Someone eats far less than their body needs until weight drops to a dangerously low level, yet when they look in the mirror they see a body that looks fine or even overweight. This is body image distortion, a core feature of the disorder: perception of size has come loose from reality. That false perception is not a side effect, it is part of what keeps the restriction going, because the person feels no urgency to eat more when the mirror seems to confirm they are not thin enough yet.

Bulimia nervosa runs on a different engine: a repeating cycle rather than steady restriction. Picture a week. Stress or hunger builds after a day or two of normal or restricted eating, then a binge happens, a discrete episode of eating an unusually large amount of food with a feeling of losing control. Shame and physical discomfort follow fast, so the person compensates: self-induced vomiting, laxatives, fasting, or excessive exercise. The compensation resets the guilt temporarily, tension builds again, and the cycle repeats, often several times a week. Because intake and compensation roughly balance out, body weight usually stays in a typical range, which is exactly why bulimia is easy to miss from the outside.

Both disorders sit next to anxiety and depression in this unit because body dissatisfaction and perfectionism feed all three, and treatment often targets the distorted thinking directly. Cultural shifts matter too: when media push thinner or more muscular ideals, body dissatisfaction rises in the population, and disorder prevalence tends to climb alongside it, especially among groups most exposed to those images.

Key terms

Anorexia nervosa
An eating disorder marked by severe food restriction, significantly low body weight, and distorted body image.
Bulimia nervosa
An eating disorder marked by repeated episodes of binge eating followed by compensatory behaviors, usually without significantly low weight.
Body image distortion
A persistent mismatch between how a person perceives their own body size and its objective reality.
Binge eating episode
A discrete period of eating an unusually large amount of food paired with a felt loss of control.
Compensatory behavior
An action like vomiting, laxative use, fasting, or excessive exercise meant to offset calories from a binge.

Watch it explained

  1. How it worksHow do anorexia nervosa and bulimia nervosa differ in behavior pattern and body weight?
  2. How it worksWalk me through the binge and compensation cycle over a week.
  3. Going furtherWhat changes in prevalence when media and cultural body ideals change?

Check yourself

Your turn1 of 2
A person with anorexia nervosa who is medically dangerously underweight looks in the mirror and genuinely perceives themselves as overweight, a perception that persists despite objective evidence and others' concerned observations. What does this specific symptom best illustrate about the disorder?

End of topic.