Sheikh Saadi (rahimahullah) has written that once a Christian king sent a doctor to the service of Rasulullah so he may tend to those requiring medical assistance. Rasulullah sent the doctor back (to the king) and said, "We are people who do not eat unless we are hungry and we do not fill our bellies when we eat, hence we do not require the services of a doctor." (Seeratul Halbiyat)

Hakeemul Ummat Hazrat Moulana Ashraf Ali Thanwi (rahmatullah alayh) explains in Tuhfatul Ulama that in overeating there can be no doubt about the detriment to one's Deen, however in this practice one also suffers worldly harm. The person who eats more spends more of his income on food. It is obvious that there will be a marked difference in the expenditure of one who eats 10 rotis (breads) and one who eats 4 rotis.

Furthermore, the person who overeats generally has digestion problems, through which various other sicknesses originate, resulting in the person spending money on medication, etc. The person who eats moderately allows his food to digest easily and remains healthy, not needing to spend money on medication.

It is regrettable that today we do not eat when we are hungry. Rather we seem to be dictated by the availability of food and specific meal times. In this way the previous meal has not yet digested completely and we take another meal. The digestive system is now under immense pressure and is unable to perform normally.