Eating disorders are psychological illnesses defined by abnormal eating habits that can involve insufficient or excessive food intake impacting physical and mental health. The most common types are anorexia nervosa, bulimia nervosa, binge eating disorder, and OSFED. Anorexia is characterized by food restriction and fear of weight gain. Bulimia involves binge eating followed by purging. Treatment for both typically involves family-based therapy, cognitive behavioral therapy, and sometimes antidepressants, with recovery often taking months or years.