Among these old arguments is the novel idea of eating less than what fills one’s belly. The Talmud teaches that people should eat enough to fill a third of their stomachs, drink enough to fill another third, and leave a third empty. A hadith in the Islamic tradition also teaches this. Rashi, a medieval French rabbi, interpreted the Talmud to mean that the final empty third is necessary so that the body can metabolize emotions. If one ate until one’s belly was completely full, there’d be no room left to manage one’s emotions and one would burst asunder.