You are what you eat Meaning the notion that to be fit and healthy you need to eat good food. Origin: This phrase has come to us via quite a tortuous route. Anthelme Brillat-Savarin wrote, in Physiologie du Gout, ou Meditations de Gastronomie Transcendante, 1826: "Dis-moi ce que tu manges, je te dirai ce que tu es." [Tell me what you eat and I will tell you what you are]. They were stating that that the food one eats has a bearing on what one's state of mind and health.