Rules of eating in the Laws of Manu
Having collected as much food as is required (from several persons), and having announced it without guile to his teacher, let him eat, turning his face towards the east, and having purified himself by sipping water.
(His meal will procure) long life, if he eats facing the north; fame, if he turns to the south; prosperity, if he turns to the west; truthfulness, if he faces the east.
Let a twice-born man always eat his food with concentrated mind, after performing an ablution; and after he has eaten, let him duly cleanse himself with water and sprinkle the cavities (of his head).
Let him always worship his food, and eat it without contempt; when he sees it, let him rejoice, show a pleased face, and pray that he may always obtain it.
Food, that is always worshipped, gives strength and manly vigor; but eaten irreverently, it destroys them both.
Let him not give to any man what he leaves, and beware of eating between (the two meal-times); let him not over-eat himself, nor go anywhere without having purified himself (after his meal).
Excessive eating is prejudicial to health, to fame, and to (bliss in) heaven; it prevents (the acquisition of) spiritual merit, and is odious among men; one ought, for these reasons, to avoid it carefully.