I think they confuse yoyo dieting fads and intense bodily shame with an ed.  They probably had some sort of diet/binge cycle because they never bothered to learn about actual healthy eating/lifestyle and went "this is unhealthy, I'm anorexic".    No, you're just miserable because you're dieting and failing and generally treating yourself like shit.  A true anorexic is not 50 lbs overweight, that's retarded.