Anorexia Nervosa, in medicine, a condition characterized by intense fear of gaining weight or becoming obese, as well as a distorted body image, leading to an excessive weight loss from restricting food intake and excessive exercise. Anorexia nervosa is not associated with any preexisting physical illness. It is found chiefly in adolescents, especially young women. Between 5 and 18 percent of known anorexia nervosa victims die of starvation, and the condition may also lead to abnormalities in the menstrual cycle and increased susceptibility to infection. Persons with the condition may also exhibit the practice, known as bulimia, of ingesting large quantities of food and then voiding it through self-induced vomiting in order to remain thin. Repeated vomiting depletes the body of fluids and of the element potassium, and the disturbance can adversely affect heart function.