ETIQUETTE

Encyclopaedia of Ismailism by Mumtaz Ali Tajddin

"The key verbal roots occur more than two dozen times each in the Koran with –k-l and sh-r-b appears together eight times. The most famous occurrence is in 7:31, where God says the children of Adam to dress properly when attending the mosque, and to “eat and drink, but avoid excess for He does not love the intemperate,” and “Eat of what your Lord has given you (kulu min rizqi rabbikum) and render thanks to Him” (34:15).

In addition to rules and regulations for the better relation of a man with man, there are certain regulations of a general nature, the object of which is to teach man ways of healthy living. These regulations relate to food, drinks, clothes, etc., and have a physical and moral values. The food that a man uses, nay even his dress, effects not only his constitution but also the building up of his character, and hence in a complete code of life, it was necessary that man should be taught manners of eating, drinking and dressing. These regulations are imparted in Islam in a recommendatory nature. It is necessary however to eat and drink moderately, otherwise many diseases occur due to gluttony, such as polyphagia, which in turn, gives birth to many other diseases. The Koran also says: “And eat and drink, but be not prodigal. Indeed, He does not love the prodigals” (7:31)."

see:
Etiquette of Eating
Etiquette of Drinking
Etiquette of Clothing