Bulimia Nervosa is characterized by repeated episodes of binge eating followed by inappropriate compensatory behaviors such as self-induced vomiting, misuse of laxatives, diuretics, or other medications, fasting, or excessive exercise.  In addition, self-image is greatly influenced by shape and weight.

Anorexia Nervosa is essentially characterized by a refusal to maintain minimally normal body weight (body weight less than 85% of what is expected for age and height).  In addition, there is intense fear of gaining weight, mis-perception of body size or shape or denial of seriousness of current low body weight, and absence of menstruation.