The partaking of food has three degrees: abstinence, adequacy and satiety. To abstain, means to remain a little hungry after eating; to eat adequately, means neither to be hungry, nor weighed down. But eating beyond satiety is the door to belly-madness, through which lust comes in. But you, firm in knowledge, choose what is best for you, according to your powers, without overstepping the limits...
I shall speak first about control of the stomach, the opposite to gluttony, and about how to fast and what and how much to eat. I shall say nothing on my own account, but only what I have received from the Holy Fathers. They have not given us only a single rule for fasting or a single standard and measure for eating, because not everyone has the same strength; age, illness or delicacy of body create differences. But they have given us all a single goal: to avoid over-eating and the filling of our bellies... A clear rule for self-control handed down by the Fathers is this: stop eating while still hungry and do not continue until you are satisfied.
For now is the time to labor for the Lord, for salvation is found in the day of affliction: for it is written: 'In your patience gain ye your souls' (Luke 21:19)
The body is a slave, the soul a sovereign, and therefore it is due to Divine mercy when the body is worn out by illness: for thereby the passions are weakened, and a man comes to himself; indeed, bodily illness itself is sometimes caused by the passions.
Fasting was of no benefit to that Pharisee in the Gospel, even though he always fasted two days a week, because he had adulterated it with pride and condemnation of his neighbor (Luke 18:11-12). Not that this means fasting is unprofitable. Moses, Elijah & the Lord Himself showed how beneficial it is for those who fast properly in a way pleasing to God.
We must not only keep a sharp watch over our diet, but keep away from all other kinds of sin so that as our stomach keeps fast, so also may our tongue as we abstain from calumny, from deceit, from idle talk, from railing and anger and all other vices which arise from the tongue. So also let our eyes keep fast. No looking for trivialities, no letting the eyes wander freely, no impudent lying in wait for people to talk to. The same with the hands and feet, to prevent them from doing anything evil. Fasting in this way, as St. Basil says, is an acceptable fast and, leaving behind all the evil to which our senses are inclined, we may come to the holy day of Resurrection, renewed and clean and worthy to share in the Holy Mysteries.
The right practice of abstinence is needful not only to the mortification of the flesh but also to the purification of the mind. For the mind then only keeps holy and spiritual fast when it rejects the food of error and the poison of falsehood.
The Holy Fathers recommend 'moderate' fasting; one ought not to allow the body to be weakened too much, for then the soul, too, is harmed. Nor ought one to undertake fasting too suddenly; everything demands practice, and each one should look to his own nature and occupation. To choose among different kinds of food is to be condemned; all food is God-given, but it is advisable to avoid such kinds as add to the body's weight and appetite; strong spices, meat, spirituous drinks and such foods as are solely for the palate's enjoyment. For the rest, one may eat what is cheap and most easily available, they say. But by 'moderate' they mean one meal a day, and that one light enough not to fill the stomach to satiety.
If a king wanted to take possession of his enemy's city, he would begin by cutting off the water and the food and so his enemies, dying of hunger, would submit to him. It is the same with the passions of the flesh; if a man goes about fasting and hungry the enemies of his soul grow weak.
When you fast and are nourished with abstinence, do not store the leftovers for tomorrow, but, as the Lord became poor and enriched us, feed someone who does not want to be hungry, you who hungers willingly. Then your fast will be like the dove who brings and joyfully proclaims salvation to your soul from the flood.
The spiritual discipline of fasting is a tool for shifting the focus away from us and toward the Lord and our brothers and sisters in whom we encounter Him each day. If we distort fasting into a private religious accomplishment to prove how holy we are, we would do better not to fast at all. That would simply be a way of serving ourselves instead of God and those who bear His image and likeness. In Lent, our focus must be set squarely on Christ and His living icons, not on us. The fundamental calling of the Christian life is to become like our Lord, Who offered Himself up for the salvation of the world purely out of love. If we are truly in communion with Him, then we too must offer up ourselves for our neighbors. And as He taught in the parable of the Good Samaritan, there are no limits on what it means to be a neighbor to anyone who is in need, regardless of nationality, culture, or anything else. Those who limit their concern for people according to such standards place serving the kingdoms of this world before fidelity to the Kingdom of God.
The body can neither love nor hate. Neither can a body fall in love with a body. The capability for love belongs to the soul. When the soul is in love with the body, that is not love but desire, lust. When the soul is in love with the soul, but not through God, that is either admiration, or pity. However, when the soul, through God loves the soul, without consideration for the appearance of the body - beauty or ugliness - that is love. That is true love. For in love is life.
Bodily purity is primarily attained through fasting, and through bodily purity comes spiritual purity. Abstinence from food, according to the words of that son of grace, St. Ephraim the Syrian, means: 'Not to desire or demand much food, either sweet or costly; to eat nothing outside the stated times; not to give oneself over to gratification of the appetite; not to stir up hunger in oneself by looking at good food; and not to desire one or another sort of food.
Almsgiving heals the soul's incensive power; fasting withers sensual desire; prayer purifies the intellect and prepares it for contemplation of created beings. For the Lord has given us commandments which correspond to the powers of the soul.
If the soul is vigilant and withdraws from all distraction and abandons its own will, then the spirit of God invades it and it can conceive because it is free to do so.
Concerning fasting, do not grieve, as I have said to you before: God does not demand of anyone labors beyond his strength. And indeed, what is fasting if not a punishment of the body in order to humble a healthy body and make it infirm for passions, according to the word of the Apostle: 'When I am weak, then am I strong' (II Corinthians 12:10).