In the Air. Each monster hasa mega food special, and other foods that will fill you up. Packs are great, and tourist traps better. Smash your buddy enough times, and you'll get a grudge match. To stay alive, you gotta eat, but eat like a pro, not a pig.
People are good, but they are a bit too skinny to be satisfying.
Try something like ice cream or cakes. Better yet, stock up on some of those nifty mega foods. Of course, you can never forget about livestocks or those greasy fast foods. Heh, even Julia can't cook a damn worth when feeding a monster hunger craving. Keep an eye out for Toxic, the purple kind.