Sayyiduna al-Miqdam bin Ma'di Karib al-Kindi (may Allah be pleased with him) said that the Messenger of Allah (peace and blessings be upon him) said: "No human being has filled a vessel worse than a stomach. A few morsels that keep his back upright are sufficient for the son of Adam. If he must eat more, then let him keep one third for food, one third for drink, and one third empty for his breath."
Hadith Referenceالمعجم الكبير للطبراني / باب الميم / 17778