“I heard the Messenger of Allah (ﷺ) say:
‘A
human being fills no worse vessel than his stomach. It is
sufficient
for a human being to eat a few mouthfuls to keep his spine
straight.
But if he must (fill it), then one third of food, one third
for drink
and one third for air.’”
Sunan Ibn Majah Book 29, Hadith 99