Relationship between eating disorders and obesity or thinness
Eating disorder influences the calorie intake which in turn affects weight gain or loss, or obesity or thinness.
Most people with binge eating disorder characterized by excessive eating become obese as the disorder contributes to their consumption of excessive calories which in turn lead to the increase of their body weight. And at the same time obese people or even people of healthy weights are more prone to binge eating disorder.
In contrast, most people affected with bulimia nervosa type eating disorder which is characterized by excessive eating followed by purging, fasting or exercise in order to compensate over-eating have or obtain a normal or near-normal weight, because in this case redundant calorie intake is compensated by calorie reduction. And most people affected with anorexia nervosa type eating disorder which is characterized by lack of food taking are thin or become thin, because in this case calorie intake is largely insufficient for their bodies.