I would like to make a few comments concerning fasting and attendance on Feast Days (holy days).
In the Eastern Church there are times of prescribed fasting. In our Byzantine Catholic Church Fridays are days of fasting. However there are exceptions, such as during bright week, the Week after Pascha(Easter)There is to be no fasting on Friday. The Friday after Pentecost is a Friday without fasting. However, we do fast on the Feast day of the Exaltation of the Holy Cross. We fast during the Great Fast (Lent), Philip's Fast (advent) and other specified times during the year.
On our calendar we have 21 Feast days not counting those that fall on Sundays, such as Easter. While some of these Feast days are listed as Obligatory and others are not, we have to look at attendance and participation from an Eastern perspective.
We pray, we attend church services, we fast in order to grow closer to God. If we come to the Divine Liturgy (Mass) on a Sunday or a Feast day because it is an obligation we are missing the point. We come out of love for God. We come to participate in praising God and thanking Him for all He has given us. We come to integrate our life with God. To just attend church because we are afraid of punishment for a sin is not the proper Eastern perspective.
Again fasting is done to grow closer to God. In the Eastern Church there are various levels of fasting. Fasting is to be done by all church members no matter what their age. Dispensations can be given for illness or other reasons deemed proper. Just being young or old is not a reason.
Usually during fasting periods there is a minimum set, but people are encouraged to go beyond the minimum if they are able. When we fast however, we are not just to fast with what goes in our mouth, but what comes out, with what we say, or do, how we treat others.
To Qoute Archbishop Joseph Raya from his book "The Face of God." "Sin is not only the breaking of a commandment or the violation of a law of God. It is also a self-glorificaiton, a self-exaltation, a refusal to recognize God as the center and the focal point of on's life and love."
If we base everything on the law and not on love of God then we are no better then the Pharisees.
All sin is a moving away from God of puting "I" first. Therefor whether a sin is great (Mortal)or small(venial) it is separating oneself from God. Sin damages us. It weakens our communion with God. The stress in the Eastern Church is not on What kind of sin but on sin itself, all sin. The stress is actually on avoiding sin, overcoming the temptation of sin, The Love of God, and the attempt to be with Him. If we are close to God we will find it easier to avoid sin.
I had better stop, before I write a book here. I'm not sure I have answered the initial question or just muddied the water more.
Father Deacon Paul
Glory to Jesus Christ! Glory to Him Forever!