An eating disorder is a mental disorder defined by abnormal eating habits that negatively affect a person's physical and/or mental health. They include binge eating disorder, where people eat a large amount in a short period of time; anorexia nervosa, where people eat very little due to a fear of gaining weight and thus have a low body weight; bulimia nervosa, where people eat a lot and then try to rid themselves of the food; pica, where people eat non-food items; rumination syndrome, where people regurgitate food; avoidant/restrictive food intake disorder (ARFID), where people have a reduced or selective food intake due to some psychological reasons (see below); and a group of other specified feeding or eating disorders. [Source: Wikipedia ]