Sayyiduna Miqdam bin Ma'dikarib رضي الله عنه narrates that the Noble Prophet صلى الله عليه وآله وسلم said: The son of Adam has not filled any vessel worse than his stomach. It is sufficient for the son of Adam to eat a few morsels to keep his back straight. But if he must eat more, then let him fill one third of his stomach with food, one third with drink, and leave one third for breathing.

It is narrated from Nafi‘ that Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) saw a poor man, brought him near, and placed food before him. He ate a lot, so Abdullah bin Umar said to Nafi‘: Do not bring him to me again, because I heard the Noble Prophet (peace and blessings be upon him) say that a disbeliever eats with seven intestines.

(Second chain) The Noble Prophet, peace and blessings be upon him, said: A believer eats in one intestine, and a disbeliever eats in seven intestines.

Syedna Abu Hurairah (may Allah be pleased with him) narrates: A man came to the Noble Prophet (peace and blessings be upon him), at that time he was a disbeliever and used to eat excessively. Then when he became a Muslim, he began to eat less. When he mentioned this to the Noble Prophet (peace and blessings be upon him), he (peace and blessings be upon him) said: A disbeliever eats with seven intestines, and a Muslim eats with one intestine.

It is narrated from Sayyiduna Abu Basrah Ghifari (may Allah be pleased with him), he says: Before accepting Islam, when I migrated, I came to the Noble Prophet (peace and blessings be upon him). He milked a goat for me, which he (peace and blessings be upon him) used to milk for his family. I drank all of it. When morning came, I became a Muslim. The family of the Prophet (peace and blessings be upon him) said: Tonight too, we will pass the night in hunger just as we did the previous night. The Noble Prophet (peace and blessings be upon him) milked the goat for me, I drank and became satiated. The Noble Prophet (peace and blessings be upon him) asked me: Are you satiated? I said: Yes, O Messenger of Allah! I am fully satiated, never before have I been so full. The Prophet (peace and blessings be upon him) said: The disbeliever eats in seven intestines, and the believer eats in one intestine.

Sayyida Maymunah bint Harith (may Allah be pleased with her) narrates that the Noble Prophet (peace and blessings be upon him) said: The disbeliever eats with seven intestines, and the believer eats with one intestine.