Eating disorders are real, treatable medical illnesses. They frequently coexist with other illnesses such as depression, substance abuse, or anxiety disorders. Eating disorders frequently appear during the teen years or young adulthood but also may develop during childhood or later in life. Eating disorders such as anorexia nervosa, bulimia nervosa, and binge-eating disorder, and their variants, all feature serious disturbances in eating behavior and weight regulation. They are associated with a wide range of adverse psychological, physical, and social consequences.