Sahih al-Bukhari 5397
Book 70: Food, Meals · Narrated by Abu Huraira
Arabic
حَدَّثَنَا سُلَيْمَانُ بْنُ حَرْبٍ، حَدَّثَنَا شُعْبَةُ، عَنْ عَدِيِّ بْنِ ثَابِتٍ، عَنْ أَبِي حَازِمٍ، عَنْ أَبِي هُرَيْرَةَ، أَنَّ رَجُلاً، كَانَ يَأْكُلُ أَكْلاً كَثِيرًا، فَأَسْلَمَ فَكَانَ يَأْكُلُ أَكْلاً قَلِيلاً، فَذُكِرَ ذَلِكَ لِلنَّبِيِّ صلى الله عليه وسلم فَقَالَ " إِنَّ الْمُؤْمِنَ يَأْكُلُ فِي مِعًى وَاحِدٍ، وَالْكَافِرَ يَأْكُلُ فِي سَبْعَةِ أَمْعَاءٍ ".
English translation
Narrated Abu Huraira:A man used to eat much, but when he embraced Islam, he started eating less. That was mentioned to the Prophet (ﷺ) who then said, "A believer eats in one intestine (is satisfied with a little food) and a Kafir eats in seven intestines (eats much)
Reference: Sahih al-Bukhari 5397, Book of Food, Meals. English translation by Dr. Muhammad Muhsin Khan.