The more stops you introduce in getting a food—such as needing to open a package or having to thaw something frozen—the more opportunities you have to ask, “Am I really hungry?” explains Wansink. Repackage cookies in single-portion bags (or pay more for individually portioned snacks); wrap leftover slices of lasagna individually in foil and freeze. No choice but to serve yourself from a large (shared) portion? Dish your portion onto a small plate. Studies by Wansink and others have shown that when served food in bigger containers, people eat more.