Binge eating symptoms are also present in bulimia nervosa. The formal diagnosis criteria are similar in that subjects must binge at least twice per week for a minimum period of three months. Unlike in bulimia, those with BED do not purge, fast or engage in strenuous exercise after binge eating. Additionally, bulimics are typically of normal weight, are underweight but have been overweight before, or are slightly overweight, whereas those with binge eating disorder are more likely to be overweight or obese.
Binge eating disorder is similar to, but distinct from, compulsive overeating. Those with BED do not have a compulsion to overeat and do not spend a great deal of time fantasizing about food. On the contrary, some people with binge eating disorder have very negative feelings about food. As with other eating disorders, binge eating is an "expressive disorder"—a disorder that is an expression of deeper psychological problems. Some researchers believe BED is a milder form or subset of bulimia nervosa, while others argue that it is its own distinct disorder. Currently, the DSM-IV categorizes it under Eating disorder not otherwise specified (EDNOS), an indication that more research is needed.