Anorexia nervosa is an eating disorder characterized by immoderate food restriction, inappropriate eating habits or rituals, obsession with having a thin figure, and an irrational fear of weight gain, as well as a distorted body self-perception. It typically involves excessive weight loss and is diagnosed approximately nine times more often in females than in males. Due to their fear of gaining weight, individuals with this disorder restrict the amount of food they consume. Outside of medical literature, the terms anorexia nervosa and anorexia are often used interchangeably; however, anorexia is simply a medical term for lack of appetite, and the majority of individuals afflicted with anorexia nervosa do not, in fact, lose their appetites. Patients with anorexia nervosa often experience dizziness, headaches, drowsiness, fever, and a lack of energy.