DefinitionAnorexia nervosa is an eating disorder that involves an inability to stay at the minimum body weight considered healthy for the person's age and height.Persons with this disorder may have an intense fear of weight gain, even when they are underweight. They may use extreme dieting, excessive exercise, or other methods to lose weight.See also:BulimiaAlternative NamesEating disorder - anorexiaCauses, incidence, and risk factorsThe exact causes of anorexia nervosa are unknown. Many factors probably are involved. Genetics and hormones may play a role. Social attitudes that promote unrealistically thin body types may also contribute.More and more evidence points away from the idea that conflicts within a family may contribute to this or other eating disorders. Most mental health organi