Bulimia nervosa is an eating disorder characterized by episodes of binge eating — consuming a lot of food quickly — followed by compensatory behavior, most commonly vomiting or "purging." People who are bulimic often feel a lack of control over their eating. A bulimic can consume as many as 3,400 calories in little more than an hour and as many as 20,000 calories in eight hours.
People with bulimia often know they have a problem and are afraid of their inability to stop eating. Bingeing is then followed by purging — namely, self-induced vomiting or the abuse of diuretics or laxatives. Bingeing and purging are often performed in secret, with feelings of shame alternating with relief.
Unlike those with anorexia, people with bulimia can maintain a normal weight for their age. But like people with anorexia, they often fear gaining weight, want desperately to lose weight, and are intensely unhappy with their body size and shape, which may explain why bulimic behavior often takes place in secret. The bingeing and purging cycle is usually repeated several times a week. As with anorexia, people with bulimia often have coexisting psychological illnesses, such as depression, anxiety, and substance abuse problems. Many physical dysfunctions result from the purging, including electrolyte imbalances, gastrointestinal troubles, and dental problems.
An estimated one to four percent of females have bulimia nervosa during their lifetime. The prevalence in males is unknown, but bulimia nervosa is far less common in males than females. Most cases begin in the late teens and early 20s, but can go undetected until the 30s or 40s.