Think of it this way. The armpit on a normal person smells because of the sweat and bacteria in a warm dark area the doesn't get a lot of air. Now think of fats, every flap, fold, and slab of flab has those same conditions plus they sweat more than a normal person anyway.  So every eat beast's entire body pretty much is one gigantic unwashed armpit.  TL;DR? Deodorant to a fat doesn't really help unless you were to roll them in it like batter on their favorite fried foods. Even then don't get your hopes up.