Bulimia nervosa is an eating disorder characterized by binge eating and purging, or consuming a large amount of food in a short amount of time followed by an attempt to rid oneself of the food consumed (purging), typically by vomiting, taking a laxative, diuretic, or stimulant, and/or excessive exercise, because of an extensive concern for body weight. Some individuals may tend to alternate between bulimia nervosa and anorexia nervosa. Bulimia is also commonly accompanied with fasting over an extended period of time.