HOW TO PARTAKE OF FOOD
-- What shall I say about the belly, the queen of the passions? If you can deaden or half-deaden it, do not relent. It has mastered me, beloved, and I worship it as a slave and vassal, this abettor of the demons and dwelling-place of the passions. Through it we fall and through it -- when it is well-disciplined -- we rise again. Through it we have lost both our original divine status and also our second divine status, that which was bestowed on us when after our initial corruption we are renewed in Christ through baptism, and from which we have lapsed once more, separating ourselves from God through out neglect of the commandments, even though in our ignorance we exalt ourselves. We think that we are with God, but it is only by keeping the commandments that we advance, guarding and increasing the grace bestowed upon us.
-- As the fathers have pointed out, bodies vary greatly in their need for food. One person needs little, another much to sustain his physical strength, each according to his capacity and habit. A hesychast, however, should always eat too little, never too much. For when the stomach is heavy the intellect is clouded, and you cannot pray resolutely and with purity. On the contrary, made drowsy by the effects of too much food you are soon induced to sleep; and as you sleep the food produces countless fantasies in your mind. Thus in my opinion if you want to attain salvation and strive for the Lord's sake to lead a life of stillness, you should be satisfied with a pound of bread and three or four cups of water or wine daily, taking at appropriate times a little from whatever victuals happen to be at hand, but never eating to satiety. In this way you will avoid growing conceited, and by thanking God for everything you will show no disdain for the excellent things He has made. This is the counsel of those who are wise in such matters. For those weak in faith and soul, abstinence from specific types of food is most beneficial; St. Paul exhorts them to eat herbs (Romans 14:2), for they do not believe that God will preserve them.
-- What shall I say? You are old, yet have asked for a rule, and an extremely severe one at that. Younger people cannot keep to a strict rule by weight and measure, so how will you keep to it? Because you are ill, you should be entirely free in partaking of food. If you eat too much, repent and try again. Always act like this -- lapsing and recovering again, and always blaming yourself and no one else -- and you will be at peace, wisely converting such lapses into victories, as Scripture says. But do not exceed the limit I set down above, and this will be enough, for no other food strengthens the body as much as bread and water. That is why the prophet disregarded everything else and simply said, "Son of man, by weight you will eat your bread and by measure you will drink water" (Ezekiel 4:16).
-- There are three degrees of eating: self-control, sufficiency and satiety. Self-control is to be hungry after having eaten. Sufficiency is to be neither hungry nor weighed down. Satiety is to be slightly weighed down. To eat again after reaching the point of satiety is to open the door of gluttony, through which unchastity comes in. Attentive to these distinctions, choose what is best for you according to your powers, not overstepping the limits. For according to St. Paul only the perfect can be both hungry and full, and at the same time be strong in all things (Philippians 4:12).
from The Philokalia: Volume IV, edited and translated by G. E. H. Palmer, Philip Sherrard, and Bishop Kallistos Ware, (London: Faber and Faber, 1995), pp. 280 - 281.