Sahih al-Bukhari 5396
صحيح البخاري#5396SahihNarrated Abu Huraira:Allah's Messenger (ﷺ) said, "A Muslim eats in one intestine (i.e. he is satisfied with a little food) while a Kafir (unbeliever) eats in seven intestines (eats much)
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Every narration in Sahih al-Bukhari is accepted as Sahih (authentic) by the established status of the book.
In-book reference: 70:24