The son of Adam does not fill any vessel worse than his stomach. It is enough for the son of Adam to eat a few mouthfuls to straighten his back, but if he must (fill his stomach), then one-third for his food, one-third for his drink, and one-third for his breath
Al-Miqdām ibn Ma‘di Karib (may Allah be pleased with him) reported: I heard the Messenger of Allah (ﷺ) say: "The son of Adam does not fill any vessel worse than his stomach. It is enough for the son of Adam to eat a few mouthfuls to straighten his back, but if he must (…

