عَنْ أَبِي هُرَيْرَةَ رَضِيَ اللَّهُ عَنْهُ أَنَّ رَجُلًا أَتَى النَّبِيَّ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ وَهُوَ كَافِرٌ فَكَانَ يَأْكُلُ أَكْلًا كَثِيرًا ثُمَّ أَنَّهُ أَسْلَمَ فَكَانَ يَأْكُلُ أَكْلًا قَلِيلًا فَذَكَرَ ذَلِكَ لِلنَّبِيِّ صَلَّى اللَّهُ عَلَيْهِ وَآلِهِ وَسَلَّمَ فَقَالَ إِنَّ الْكَافِرَ يَأْكُلُ فِي سَبْعَةِ أَمْعَاءٍ وَإِنَّ الْمُسْلِمَ يَأْكُلُ فِي مِعًى وَاحِدٍ
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.