I'm very skinny and often get comments that I can and do eat anything, but I think I have some traits that make it easy for me: I hate ice cream (that fatty feeling in your mouth, ugh, I do love me some butter though!), in fact I don't like most desserts at all. I always prefer savory stuff (like a sandwich or olives for snacking) over sweet things (like cookies or candy). And I never get hungry anymore at night after a good dinner. My wife can each crisps 2 hours after dinner, I don't know how she does it. Or even how people can eat a piece of pie after a fulfilling meal, it just doesn't fit anymore. This could be genetic.