I work on always having enough food while working on research. The best way to get A LOT of food soon is to have a few babies, then when they are 2 years old, I go around the island looking for mushrooms and when I find one, I pause the game, then put every child I have on it. That one mushroom (hope it is a red one) multiplies into however many children picked it. Even 6 children on a brown mushroom is 48 food. (That would be 270 food for a red mushroom.)