Anorexia nervosa (AN), also known as simply Anorexia, is an eating disorder characterized by refusal to maintain a healthy body weight and an obsessive fear of gaining weight. It is often coupled with a distorted self image which may be maintained by various cognitive biases that alter how the affected individual evaluates and thinks about her or his body, food and eating. Persons with anorexia nervosa continue to feel hunger, but deny themselves all but very small quantities of food. The average caloric intake of a person with anorexia nervosa is 600–800 calories per day, but extreme cases of complete self-starvation are known. It is a serious mental illness with a high incidence ofcomorbidity and the highest mortality rate of any psychiatric disorder.
Anorexia most often has its onset in adolescence and is most prevalent among adolescent girls. However, more recent studies show that the onset age of anorexia decreased from an average of 13 to 17 years of age to 9 to 12. While it can affect men and women of any age,race, and socioeconomic and cultural background, Anorexia nervosa occurs in females 10 times more than in males.