Not forbidden to eat until full unless harm feared
12-10-2015 | IslamWeb
Question:
Were any of the 'Ulamaa' of the opinion that it is haraam to fill more than a third of one's stomach with food and a third of one's stomach with drink? Were they of the view that it is makrooh or that it is mustahabb to not go over filling a third with food and a third with drink?
Answer:
All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad 
is His slave and Messenger.
It is not forbidden to eat until becoming full if one does not fear harm from doing so, as the Companions sometimes ate until they became full. Al-Bukhari 
narrated that “the Prophet gave Abu Hurayrah milk and he 
drank, and the Prophet told him to drink again and again. And he drank until he said to him, "I swear by He Who has sent you with the truth, I cannot find any more space for it."”
Also, Al-Bukhari and Muslim reported that Jaabir cooked food and the Prophet called the people of the Trench to eat with them, and then he said to Jaabir, "Let ten people come in," so he let in ten people and they ate until they were full.” For more benefit, please refer to Fatwa 279682.
However, some scholars disliked eating more than necessary as it involves extravagance. Shaykh-ul-Islam Ibn Taymiyyah and a group of scholars from the Hanbali School forbade eating in excess if it leads to harm or indigestion.
Ibn Al-Qayyim said: “If the stomach is filled with food, it will not have enough space for drink, and when the drink is added to it, it leaves even less space for breathing, so the stomach experiences distress and fatigue, and it bears this like one carrying a heavy burden. This state will also lead to heart trouble and the limbs becoming too lazy to perform the obligatory rites as they move swiftly into submission to desires brought about by overindulgence. So, filling one's stomach with food is harmful for both the heart and body. However, if done only occasionally, there is no harm. Abu Hurayrah drank milk in the presence of the Prophet until he said, "I swear by the One Who has sent you with the truth, I cannot find any more space for it." And the Companions often ate in his (the Prophet’s) presence, until they were full.
Excessive overindulgence, however, weakens one’s energy and body, even if it nourishes it. The body strengthens in proportion to the quality of the food that it takes in and not the quantity.”
According to Manaar As-Sabeel (a Hanbali book): “It is disliked for one to eat so much that the food harms him, but it is permissible to eat a lot if this does not harm the person. Al-Iqnaa‘ reads: "If harm or indigestion is feared, it is forbidden."”
Al-Mubdi‘ a commentary on the Muqni’ (a Hanbali book) reads: “It is permissible for one to eat a lot if this does not harm him. Al-Ghunyah reads: It is disliked when fearing indigestion. Shaykh Taqiyy Ad-Deen forbade it, and (he also forbade) excessively eating beyond bounds.”
Allaah Knows best.