…Fasting is essential. And as everything else in the Church, fasting is regulated by the ustav. There, in the Typikon, one finds written down when oil can or cannot be consumed, when eating fish is permitted, and so on. However, before choosing the Typikon as one’s immutable guide in the matter of fasting, one should recall that this is an ancient monastic ustav, an ustav for ancient, true spiritual strugglers and not show-offs, for spiritual strugglers for whom the rigor of physical fasting was entirely consonant with their abstinence in matters spiritual and moral. For them, spiritual and physical life were in complete harmony. Therefore, for contemporary lovers of glamour magazines and the “Realm of Miracles,” fasting according to the Typikon is simply a mockery and profanation of the fast.
It is also essential to note that fasting strictly, according to the ustav, presumes that the person is healthy; it is entirely inappropriate for the sick, the elderly, children, pregnant or nursing women, or for people engaged in arduous physical labor. In such cases, the ustav gives way to objective human needs.
There is nothing anti-Orthodox in peasants who work in the fields in the Spring, during Lent, being permitted to have dairy products, or for students (including seminarians) to be permitted to eat fish, for after all, the Typikon is not something that simply fell down to us from Heaven. It was written by people. One of the clearest indications of its human origin lies in the opening words of the chapter on the Holy Quadragesima [Great Lent]: “In the morning of Monday of the first week, the paraecclesiarch [sexton] calls the brethren together for prayer later than usual, because of last night’s “evening consolation.” In the language of the Typikon, the term “consolation” refers to the presence of wine at the monastic meal, and from a strictly human standpoint, it is quite easy to understand that for someone who the night before had drunk more alcohol than usual, sleeping a bit later today would do no harm. It would be good for our excessively zealous proponents of the ustav to remember its human character.
In fasting physically, one must not forget why he is fasting, what goal is furthered by that religious resource. Fasting is a spiritual effort of a common religious unity, not merely a unity of traditionalism, not merely an expression of oneness of our beliefs, but first of all the expression of Eucharistic unity, without which fasting becomes nothing but an empty, external form.
The historical account of persecutions under Emperor Diocletian (late 3rd to early 4th century) provides an excellent example of the proper attitude toward the Eucharist. Those were the most severe persecutions in the entire three centuries of persecution. No one before Diocletian had shed so much Christian blood.
The Emperor, who was by no means stupid, found the Church’s principal nerve center, and struck a blow against it. He decreed that it was against the law for Christians to gather for the Eucharist, and that those who participated in such gatherings were criminals guilty of a capital offense. Diocletian issued such instructions knowing full well that Christians would be unable to stop attending Eucharistic gatherings, would be unable to live without Communion. Of course, he was not mistaken; to the early Christians, the opportunity to take part in the Eucharist was more precious than life itself.
Should a great persecutor employ such a maneuver today, one could easily imagine how busy he would be. It would seem that there is no shortage of Christians, and a shortage of people to seize them and throw them to the lions.
If we see in Lent merely a diet which precedes our going to an abundant Paschal table, we are losing a very great deal. For us, Lent is a reminder of our sinfulness, a reminder that we depend upon the material world, upon being physically sated, and that in being so dependent, we cease to be servants of Christ. Lent reminds us of our lost Heavenly Homeland. It is not for no reason that during the All-night Vigil service we hear the 136th Psalm, the mournful weeping of the Israelites in the Babylonian Captivity. That reminds us that here on earth we are in a strange land, one in which we cannot sing the Lord’s song.
The essence of Lent lies not in the fast, but in Pascha. In turn, the essence of Pascha lies in salvation, in theosis [deification] of the human race, which is granted to us through Communion.
Therefore Orthodox fasting, like Christian life in general, must bear witness to the fact that Christians live for something, because of which they are not afraid to die. And that is why Diocletian was not mistaken.
Taken (and presented here in a somewhat abridged form) from: http://kiev-orthodox.org/site/faithbasis/1111/