The Messenger of Allah ﷺ said, "The disbeliever eats with seven intestines, while the believer eats with one."
قال رسول الله ﷺ: الكافر يأكل في سبعة أمعاء والمؤمن يأكل في معى واحد.
Ahmad (26845) narrated it from Waki, who said, I heard Amash say, I think Abu Khalid Walibi mentioned it from Maymuna bint Harith, who said... and he related it.There is disagreement about the chain going back to Amash. Waki narrated it as you have seen, while Abdul-Rahman bin Humayd Ruasi narrated it from Amash, from Husayn bin Abdul-Rahman, from Ubaydullah bin Abdullah bin Utba, from Maymuna, and related it. This is the version that Daraqutni favored in Ilal (4018), and its chain is sahih. Husayn bin Abdul-Rahman is Sulami Abu Huzayl Kufi, one of the narrators found in all six major collections.Something with a similar meaning was narrated from Nadla bin Amr Ghifari, that he met the Messenger of Allah ﷺ twice, having with him vessels of milk. He gave the Messenger of Allah ﷺ to drink, then he himself drank what remained in the vessel, and it filled him up. He said, "O Messenger of Allah ﷺ, I used to drink the milk of seven ewes and still not be filled." The Messenger of Allah ﷺ said, "The believer drinks with one stomach, while the disbeliever drinks with seven stomachs."Ahmad (18962) narrated this from Ali bin Abdullah, who said, Muhammad bin Maen bin Muhammad bin Maen bin Nadla bin Amr Ghifari Madani told me, my grandfather Muhammad bin Maen told me, from his father Maen bin Nadla, from Nadla bin Amr Ghifari, and he related it. Its chain is daif because of Maen bin Nadla, from whom no one narrated except his son, and no one deemed him reliable except Ibn Hibban, who mentioned him in his Thiqat. He is among the narrators covered in Tajil (1057).Something with a similar meaning was also narrated from Abu Basra Ghifari. Ahmad (27226) narrated it from Yahya bin Ishaq, who said, Ibn Lahia informed us, from Abdullah bin Hubayra, from Abu Tamim Jayshani, from Abu Basra Ghifari, who said... and he related it, and it contains a story. Its chain is daif because of Yahya bin Ishaq, who is Saylahini, and I have not come across anyone who stated explicitly that he narrated from Ibn Lahia before his books were burned.As for the meaning of his saying, "The believer eats with one stomach," it has been said that this hadith was revealed concerning a particular man who used to eat and drink a great deal, so this parable was given about him. It has also been observed that when the believer mentions Allah's name over his food, no devil shares in it with him, unlike the disbeliever, who does not mention Allah's name over his food, so the devil shares in it with him, and he is not satisfied. This is what happened with the disbelieving guest whom the Messenger of Allah ﷺ hosted, who drank the milk of seven ewes, but when he became Muslim the following day, he was satisfied with the milk of just one ewe.This hadith also encourages eating and drinking little, since that is more beneficial for the body, unlike eating and drinking excessively, which harms the body and resembles the behavior of disbelievers. For this reason, Ibn Umar refused to let in the poor man who had eaten a great deal.