Eating what is ḥalāl, even if it is little, is one of the factors that aid a student of Islamic knowledge in his pursuit of knowledge.
Therefore, eating excessively is not good etiquette for a student of knowledge.
Al-Imaam Ash-Shaafi'ee رحمه الله said:
ما شبعت منذ ست عشرة سنة
I have not eaten to my fill for sixteen years.
Excessive eating leads to increased thirst, while excessive drinking leads to more sleep. This, in turn, results in sluggishness, reduced attentiveness, impaired use of the senses, and general bodily lethargy.
Furthermore, excessive eating exposes a person to legitimate blame and various bodily illnesses.
A poet said:
فإن الداء أكثر ما تراه
يكون من الطعام أو الشراب
For most of the illnesses you see arise from food or drink.
No righteous scholar has ever been described as a glutton and praised for it. Gluttony is a characteristic of beasts of burden.
Sound intelligence retains its dignity until it is tainted by vile things arising from matters related to food, thereby rendering its possessor blameworthy.
If excessive eating had no other drawback than the need to frequent the restroom, that alone would suffice to deter a sensible person from it.
Success in acquiring knowledge is hardly attained by someone who is preoccupied with an assortment of foods and drinks and the sleep that follows.
When you must eat, then let it be within reasonable limits, as the Messenger of Allaah ﷺ said:
ما ملأ ابن آدم وعاء شرًّا من بطنه، بحسب ابن آدم أكلات يقمن صلبه، فإن كان لا محالة، فثلث لطعامه، وثلث لشرابه، وثلث لنفسه.
The son of Aadam has not filled any vessel worse than his stomach. A few morsels that keep his back upright are sufficient for the son of Aadam. But if he must eat more, then let one-third be for his food, one-third for his drink, and one-third for his breathing.
Reported by At-Tirmidhi (2380).
This is the standard set by the Messenger of Allaah ﷺ. Anything beyond moderation contradicts the guidance of the Sunnah concerning eating and drinking.
Allaah, the Mighty and Majestic, says:
وَكُلُوا وَاشْرَبُوا وَلَا تُسْرِفُوا
“And eat and drink, but waste not by extravagance.” (Sooratul-A'raaf, 7:31;
Some scholars commented on this verse by saying:
“Allaah has encompassed the principles of medicine in these words.”
