How come I don't gain any weight? I eat like a cow, all of the time!?

your still young so your metabolism is still very fast. also you may just genetically have a faster metabolism than most people. if you wanna gain weight, you gotta take in more calories than you burn. are you highly active? and how quickly are you eating all that food? if you space the food out over a long period of time.. than youll probably burn off most of the calories by the time you eat again.