Musnad Ahmad 462:16

Abu al-Mughirah narrated to us, he said: Sulayman ibn Salim al-Kinani narrated to us, he said: Yahya ibn Jabir al-Ta’i narrated to us, he said: I heard al-Miqdam ibn Ma’di Karib al-Kindi, he said: I heard the Messenger of Allah, peace and blessings of Allah be upon him, saying: "The son of Adam does not fill a vessel worse than his stomach. It is sufficient for the son of Adam to have a few morsels that keep his back upright. If he must, then a third for his food, a third for his drink, and a third for his breath."