We say to ourselves most of the time. We say it when we involve in behaviors that cause short-term pleasure for long-term problems and of course guilt. For example, eating unhealthy things, being idle, staying up too late, being involved in drugs, or drinking too much. Why do we do these things? After all, aren’t we completely in control of ourselves all of the time? I think not! Studies tell us that willpower is a limited supply. Each of us only has so much of it. To be useful at controlling our wishes and making healthy decisions, the prefrontal cortex needs to be taken care of. That means feeding it with healthy food so it has enough energy to do its job and providing it enough sleep.