The system used by the body to regulate how much we consume is one of the most complex systems in the body, Kohlmeier adds."If you see the body as a big machine, with all the different components that need to come from the outside; you need to get enough water, macronutrients and micronutrients, on top of knowing what not to eat." There are several nutrients that will drive our appetite if we're deficient in them, he adds.