It's a matter of satisfaction,in my opinion. I can eat a little tiny bit of amarvelous food,but I need to eat volume to feel satisfied.   Another thing fat people can't grasp is that not all the fit people are like that because they naturally are in that way. I struggle a lot in the gym and to not overeat too much. And since I know myself I have to plan what I have to eat and when to eat it (like skipping breakfast, "OMG are you crazy,is the most important time of the day")