I have no scientific evidence to back this up, but I believe snacking on apples makes me hungrier. Reaching for an apple, I'm usually just peckish. Then I crunch, crunch, crunch and BAM. I finish, but in an altered, ravenous state. Something in that fruit stimulates the hypothalamic receptors, and my stomach starts doing hunger somersaults, growling up a storm. It's annoying, and makes me mad at apples, yet I continue to eat them.
Fellow Serious Eater Michele backs me up: "Even when I eat a full meal, then have an apple for dessert, I'm hungry again after. It gives me a gnawing feeling in the belly, like it's empty again."
Does this make any sense to anyone else?