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.
Fasting is beneficial when it is undertaken for quelling desire, humbling the soul, transforming hatred, extinguishing anger, erasing remembrance of wrongs, and for the purity of the understanding and the practice of prayer.
We are told: It is no big deal to eat non-Lenten food during Lent. It is no big deal if you wear expensive beautiful outfits, go to the theater, to parties, to masquerade balls, use beautiful expensive china, furniture, expensive carriages and dashing steeds, amass and hoard things, etc. Yet what is it that turns our heart away from God, away from the Fountain of Life? Because of what do we lose eternal life? Is it not because of gluttony, of expensive clothing like that of the rich man of the Gospel story, is it not because of theaters and masquerades? What turns us hard-hearted toward the poor and even toward our relatives? Is it not our passion for sweets, for satisfying the belly in general, for clothing, for expensive dishes, furniture, carriages, for money and other things? Is it possible to serve God and mammon, to be a friend to the world and a friend to God, to serve Christ and Belial? That is impossible. Why did Adam and Eve lose paradise, why did they fall into sin and death? Was it not because of one evil? Let us attentively consider why we do not care about the salvation of our soul, which cost the Son of God so dearly. Why do we compound sin upon sin, fall endlessly into opposing to God, into a life of vanity? Is it not because of a passion for earthly things and especially for earthly pleasures? What makes our hearts become crude? Why do we become flesh and not spirit, perverting our moral nature? Is it not because of a passion for food, drink, and other earthly comforts? How after this can one say that it does not matter whether you eat non-Lenten food during Lent? The fact that we talk this way is in fact pride, idle thought, disobedience, refusal to submit to God, and separation from Him.
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.
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.
We must not think that anyone slips and comes to ruin by a sudden fall; it is rather that he has been deceived by the beginnings of evil habits, or else, by prolonged mental negligence, virtue has little by little withdrawn from him, and vices have thereby grown stronger, and he has come thus to a miserable fall. For Pride goeth before destruction, and the spirit is lifted up before a fall (Prov.16:18 LXX). Just as a house never falls in ruin by a sudden shock unless there has been some long-standing fault in the foundations, or by the prolonged carelessness of the tenants, little driblets at first penetrate through and slowly undermine the walls, which, inconsequence of the old neglect, open in ever wider apertures and crumble away, and then let in the tempest of rain and storm in torrents. For by slothfulness a building shall be brought down, and through the weakness of hands the house shall drop through (Ecclus. 10:19 LXX).
Fasting was ordained in Paradise. The first injunction was delivered to Adam, ‘Of the tree of the knowledge of good and evil you shall not eat.’ ‘You shall not eat’ is a law of fasting and abstinence. The general argument is rather against excess than in support of ceremonial abstinence. In Paradise there was no wine, no butchery of beasts, no eating of flesh. Wine came in after the flood. Noah became drunk because wine was new to him. So fasting is older than drunkenness. Esau was defiled, and made his brother’s slave, for the sake of a single meal. It was fasting and prayer which gave Samuel to Hannah. Fasting brought forth Samson. Fasting begets prophets, strengthens strong men. Fasting makes lawgivers wise, is the soul’s safeguard, the body’s trusty comrade, the armor of the champion, the training of the athlete.
Hold faith and humility fast within you; for through them you will find mercy, help, and words spoken by God in the heart, along with a protector who stands beside you both secretly and manifestly.
Fasting is absolutely indispensable for man. From the external aspect, it is a struggle of filial obedience to God, Who has given us the rules of fasting through His Holy Spirit. From the inner aspect, fasting is a struggle of restraint and self-limitation. In this lies the great value and sense of fasting, since a strict observance of fasts tempers one's will and perfects the character of one who is firm in his religious convictions and actions. Let us not forget that Christ Himself fasted, and foretold that His apostles would also fast.
Fasting is acceptable to God when abstention from food is accompanied by refraining from sins, from envy, from hatred, from calumny, from vainglory, from wordiness, from other evils. He who is fasting the true fast `that is agreeable' to God ought to shun all these things with all his strength and zeal, and remain impregnable and unshakeable against all the attacks of the evil one that are planned from that quarter. On the other hand, he who practices abstention from food, but does not keep self-control in the face of the aforesaid passions, is like unto one who lays down splendid foundations for a house, yet takes serpents and scorpions and vipers as fellow-dwellers therein.
In no art do the artists judge the result of their work by the tools they use, but they await the work's completion and by it judge the art. Adopting such a practice with regard to food, not placing all your hope on fasting, but fasting moderately and according to the amount of your strength, strive toward mental activity. In this way you can avoid pride and will not spurn God's good works, sending up praises to God for everything.
Many abstain from meat, milk and other food which God has not forbidden and which was even given as a blessing of people who have learned the truth and know how to partake of these things with thanksgiving (I Tim. 4:34). But the same abstemious, devout-living people, give scandal by their action, and spread scandal with their tongue like an incendiary fire.
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.
It is necessary most of all for one who is fasting to curb anger, to accustom himself to meekness and condescension, to have a contrite heart, to repulse impure thoughts and desires, to examine his conscience, to put his mind to the test and to verify what good has been done by us in this or any other week, and which deficiency we have corrected in ourselves in the present week. This is true fasting.
Sear your loins by abstaining from food, and prove your heart by controlling your speech, and you will succeed in bringing the desiring and incensive powers of your soul into the service of what is noble and good.