Anorexia nervosa is an eating disorder characterized by extremely low body weight, distorted body image and an obsessive fear of gaining weight. The term anorexia nervosa was established in 1873 by Sir William Gull, one of Queen Victoria’s personal physicians. The term is of Greek origin and orexis, thus meaning a lack of desire to eat. A definition of anorexia nervosa was established by the Diagnostic and Statistical Manual of Mental Disorders (DSM-IV-TR) and the World Health Organization’s International Statistical Classification of Diseases and Related Health Problems.