I'd define fussiness is incredibly restricted eating eg chicken, bread, apple and jam. I just think they start to express a preference. And this chances from week to week. Having said that, Minky seems to have been on potato strike for weeks (she'll eat chips though). I don't agree that they necessarily avoid things that they are allergic to. Mink stuffed eggs down her like there was no tomorrow and then had a dramatic allergic reaction. But I guess a contact allergy ie stingy tomato on your chin, might be avoided more readily.