Anorexia is most common in girls. Anorexia usually started in adolescence. 1 in 150 girls suffer from anorexia.

Anorexia almost always begins with a strict diet. Patients are usually really slightly overweight at first. But even when the ideal weight is reached, patients continue to starve because their perceptions of their weight have become wrong and they still feel too fat. Often patients also engage in intense exercise or use medications that reduce weight.