I think it's absolutely an eating disorder, it's cause could be from many different reasons.
I've seen two types of people, one skinny and underfed, looking weak and then the overweight type, eating anything and everything that isn't meat.
Strangely, I think many of them don't eat the wide variety of veggies you would hope they do. That's where all of the fake, lookalike food comes in with the processed soy meal concoctions.