Maybe some, but not all and not even close to a majority. Eating disorders are real and they are usually tied to anxiety/OCD. Overeating isn't a mental illness, but a compulsion to force in food is. A good distinction: A fat person will order a whole pizza and eat the entire pizza because s/he likes pizza.      Someone with binge eating disorder will eat found pizza in a trash can even if s/he hates pizza. If you want to know more about it, you can message me.