It doesn't even need to be forced starvation. If everyone in his life stopped enabling his attributes, he would be forced to be at a weight where he has to get his own food. Him standing up requires significant weight loss. You may get to be a fat fuck, but your "loved ones" drag you across the "whale line" by excessively feeding these fat fucks when they can't feed themselves. His father even states "if he can get him up the stairs", but somehow he can still acquire excessive amounts of food. "Durr I don't know how this happens! I just deliver his hourly pizza to his room."