The ancient Christian practice of fasting on prescribed days and seasons — as the fulfillment of the Jewish fasting periods of the Old Covenant — is one that has been largely abandoned by much of modern Christianity, and especially in the west. While preparation for Christmas in our secular culture is marked chiefly by consumerism, frivolity, and indifference to spiritual matters, the Orthodox Church enters into the fast of the Nativity, one of the four fasting seasons of the year, in order to spiritually prepare ourselves for the Incarnation of the Lord.
Rather than discuss the nature of the Nativity fast specifically (you can read more on that here), I’d like to discuss the purpose of fasting more generally, and doing so in accordance with the prescriptions of the Church.
According to the Holy Fathers, the Fall distorted the proper relationship of the body to the soul. Rather than the soul being the master of the body, leading the whole of the human person in his walk with God, as was the case before the Fall, the relationship was reversed and the spirit of man became ruled by the appetites of the flesh. To continue to allow ourselves to be so ruled is to live in accordance with the law of sin and death, which Christ has overthrown. Fasting is one of the chief ways that we “discipline the body and bring it into subjection” (1 Cor. 9:27), participating in the restoration of the proper hierarchy of body and spirit within the human person.
The connection of fasting to the Fall is exemplified in the fact that the first commandment that man transgressed was breaking a fast that God had ordained in the garden. St. Isaac of Syria writes: “The first commandment given to our nature in the beginning was the fasting from food and in this the head of our race (Adam) fell. Those who wish to attain the fear of God, therefore, should begin to build where the building was first fallen. They should begin with the commandment to fast.” In recognition of the fact that fasting marks the beginning of the spiritual life, catechumens in the early Church were required to practice long periods of fasting, asceticism, and repentance in preparation for their reception into the Church on Pascha. This is how the 40 days of Great Lent developed, as members of the Church saw the spiritual struggle the catechumens would undergo and, in their zeal and love, would join them in preparation for the greatest Christian holy day. This became normalized and formalized in the 40 days of Lent that the Church still practices.
When we fast, we are to also make a concerted, increased effort at prayer, almsgiving (which we have more money for by eating less), and fasting from sins. Of course, we should always practice obedience to Christ’s commandments in all seasons, but fasting assists at directing our energies to spiritual matters that we often neglect. When we would normally feel hunger, and respond by satisfying it — by, that is, attending to the things of the world — when fasting, we want to have that hunger direct our attention to the things of God.
Following the fasting prescriptions of the Church also provides Christians with a practical means for practicing obedience and the crucifixion of self-will in a regular way. Fasting whenever we feel like it and from the foods we decide to fast from isn’t actually self-denial, but is just another expression of our own self-will, the end of which is death. Submitting to the authority of the Church which Christ established, to His very Body, is essential to cultivating a spirit of obedience and humility, which forms the core of the Christian life.
By “denying ourselves and taking up our cross” (Matt. 16:24; Luke 9:23) , rather than satisfying every desire of the flesh, we acknowledge that we are called to die with Christ, which means dying to our passions and desires—and this so that we can also raise with Him to new life. The new life in Christ is sustained by bread as well, but it’s the heavenly bread of Christ’s flesh (John 6:32-35) which Orthodox Christians feast on in the Eucharist. Fasting and the hunger pains it brings are intended to direct our gaze to that heavenly feast, and remind us that the real bread we live on is not of this world.