Short answer
Eating until you are full is allowed, but in the Hanafi school eating beyond fullness is haram, except to gain strength for the next day's fast or so a guest is not embarrassed. The Prophet ﷺ said a few bites to keep your back straight are enough, and if you must eat more, then a third for food, a third for drink and a third for breath.
Eating enough to survive is fard, eating to be able to pray and work is rewarded, eating to fullness is mubah, and eating beyond fullness is haram, except for a valid reason such as preparing for a fast or putting a guest at ease.
The four schools agree on this.
Explanation
The Prophet ﷺ said that the son of Adam fills no vessel worse than his stomach. A few mouthfuls that keep his back straight are enough; if he must eat more, then a third for food, a third for drink and a third for breath.
The Hanafi books describe levels of eating:
- Fard: enough to stay alive.
- Rewarded: enough to pray standing, fast and work.
- Mubah: eating until full, to keep up strength.
- Haram: eating beyond fullness, which harms the body, unless it is to gain strength for the next day's fast or so a guest does not feel shy to keep eating.
Fullness here means feeling satisfied, not the point of discomfort. The Prophet ﷺ also said that the believer eats in one intestine while the disbeliever eats in seven, and that food for two is enough for three. Scholars of the other schools also discourage overeating, though some class it as disliked rather than forbidden.
This matters most at iftar, Eid, weddings and buffets, where it is easy to keep going. If you struggle with binge eating or any eating disorder, that is a health condition, not simple greed: speak to a doctor, and know that Allah does not burden a soul beyond what it can bear. See also is wasting food haram.
The evidence
Quran, Surah Al-A'raaf 7:31
۞ يَٰبَنِىٓ ءَادَمَ خُذُوا۟ زِينَتَكُمْ عِندَ كُلِّ مَسْجِدٍۢ وَكُلُوا۟ وَٱشْرَبُوا۟ وَلَا تُسْرِفُوٓا۟ ۚ إِنَّهُۥ لَا يُحِبُّ ٱلْمُسْرِفِينَ ﴿٣١﴾
O children of Adam, take your adornment at every masjid, and eat and drink, but be not excessive. Indeed, He likes not those who commit excess.
Excess in eating is forbidden.
Jami' at-Tirmidhi 2380
Grading to be checked... ما ملأ آدمي وعاء شرا من بطن ...
"The son of Adam fills no vessel worse than his stomach."
The basis of the one-third guidance.
Sahih al-Bukhari 5393
Sahih... المؤمن يأكل في معى واحد ...
"The believer eats in one intestine."
Believers eat moderately.
Where the ruling is recorded
- al-Fatawa al-Hindiyya, Kitab al-Karahiyya, chapter on eating and drinking. The levels of eating, and that eating beyond fullness is forbidden except for strength to fast or for a guest's sake.
- Radd al-Muhtar (Ibn Abidin), Kitab al-Hazr wa al-Ibaha. The same levels of eating and their rulings.
Checked by our team. For a more accurate answer to your own situation, consult a scholar. Quran translation by Sahih International. Hadith Arabic from the standard editions of the six books and the Muwatta, with gradings as recorded there; the English is our own rendering. Spotted a mistake? Tell us.