More people are being diagnosed with eating disorders, possibly as a consequence of society's emphasis on and preoccupation with thinness. Eating disorders are conditions that involve genetic, biological, psychosocial, and environmental factors. In North America, anorexia nervosa, bulimia nervosa, and binge eating disorder are the most common eating disorders. More women than men are affected by eating disorders.
Anorexia nervosa is a psychiatric condition in which people restrict their food intake or use behaviours to prevent weight gain, because of an intense fear of becoming fat or obese. In reality, people affected by this condition are almost always underweight or of normal weight when the condition starts. This disorder usually starts in the years between adolescence and young adulthood, with the average age of onset at 18 years. Women are more affected by anorexia than men. Current statistics say that in their lifetimes, 9 in 1000 females and 3 in 1000 males will be diagnosed with anorexia. However, in 2013 the diagnostic criteria were modified to be less restrictive, and by this newer understanding, these numbers are an underestimation.
Bulimia nervosa is an eating disorder characterized by repeated and uncontrolled or compulsive binge eating, followed by inappropriate ways of trying to get rid of the food eaten. Most often, this involves purging by self-induced vomiting or abuse of laxatives, enemas, or diuretics. It's also sometimes called the "binge-purge syndrome." Some people with bulimia don't purge, but will binge-eat (consuming as many as 20,000 calories at one time) and then compensate for binge eating sessions with other behaviours such as fasting or over-exercising. A person with bulimia may secretly binge anywhere from once a week to several times a day.
Bulimia commonly appears in the latter part of adolescence or early adulthood, but it can develop at an earlier or later age. Like anorexia, the median age of onset for bulimia is 18 years. Bulimia also affects women more than men: about 3 times as many women as men will have it in their lifetimes.
Binge eating disorder is characterized by the same uncontrollable binge eating that is seen in bulimia nervosa, but without any purging behaviours after binge eating episodes. This condition is distinct from overeating or obesity. Previously, clinicians used the category “eating disorders not otherwise specified” to capture all eating disorders not meeting the criteria for anorexia nervosa or bulimia nervosa, but in 2013 binge eating disorder was recognized as a unique diagnosis.