Why? Because of the craziness of the period that precedes Christmas. It is filled with secular images and activities so that too often we lose the notion that we are dong all this to prepare for the Nativity of our Lord and God and Savior is lost. We need to sit down with our families and determine how we will prepare for the Coming of Christ and honor this period by our fast.
There is no need to enumerate the distractions during this period. But doesn't Santa Clause seems to get a bigger billing than Christ? Also there are all the other modern symbols of this time such as Rudolph the red nosed reindeer, Frosty the snowman, and all the other non religious Christmas stories. In addition there are the office parties and the numerous visits and gatherings of friends and neighbors where we celebrate. But when we get together what are we celebrating? This is our challenge, we must bring Christ to the center of our all our activities during this season that so many enjoy.
Elder Paisios tells us the following about fasting:
With fasting man reveals his choices. Out of philotimo, a person undertakes an ascetic discipline and God helps. But if a person forces himself and laments, "Oh well, it's Friday; I have to fast," he will surely torment himself. If however, he understands the meaning of fasting and does it out of love for Christ, he will rejoice in it and say to himself, "This is the day when Christ was crucified; they didn't even give Him water to drink; they gave Him vinegar. I, too , will not drink water all day." If he does this, then he will experience a far more sublime inner joy that the person who in joys the best refreshments.What does this mean for us in regards to the Nativity fast? It instructs to understand that by fasting we bring ourselves to an awareness of the life of Christ and how he sacrificed for us. Each time we resist a temptation to violate our fast we are brought back to the truth of our salvation. We rmeber why we are doing it and this centers us and our current activity on Christ. In this way we keep Christ in the center of our lives even in a hectic period like Advent.
Any fast must be done out of the love of God. We do it to help us remember Him.
Elder Paisios amplifies this point.
If someone doesn't get to the point of doing something, whatever it is that he chooses to do, out of love for God and his fellow human beings, he is merely wasting his time and effort. If he is fasting and has the prideful thought that he is doing something great, his fasting is wasted. He is like a vessel with holes that cannot hold any thing. Put water into a vessel with holes –– the water gradually drips away.During this period let us not be like a vessel with holes, but let us seek to fortify ourselves with a fast that will help us keep our focus on the purpose of this season.
Reference: Elder Paisios of Mount Athos Spiritual counsels IV: Family Life, pp194, 199