Greek Orthodox Archdiocese - Fasts (Nativity Fast before Dec. 25 - forty days from Nov. 15)

Fast Days and Fast Periods
Four main fast periods are included in the ecclesiastical year. They are:

1. The Great Fast (Lent)--beginning on a Monday 7 weeks before Easter.
2. Fast of the Apostles--varying in length from 1 to 6 weeks; it begins on a Monday, 8 days after Pentecost, and ends on June 28--the eve of the feast of Saints Peter and Paul.
3. Fast of the Repose of the Virgin Mary--August 1 to 14.
4. Christmas Fast--lasting 40 days, from November 15 to December 24.

Individual fast days include the feast of the Elevation of the Holy Cross (September 14), the Beheading of St. John the Baptist (August 29), and the eve of Epiphany (January 5), as well as all Wednesdays and Fridays. There is no fasting, however, between Christmas and Epiphany, during the tenth week before Easter, the week after Easter and the week after Pentecost.
Although the term denotes total abstinence from food or drink, fasting as practiced in the Orthodox Church means abstinence from meat, fish, dairy products, olive oil, and wine. Total abstinence is reserved for the fast of several hours duration preceding Holy Communion. The rules for fasting prescribed by the holy canons are quite rigid; and, although they are still observed in the monasteries and by the very devout, most Orthodox Christians today find it difficult to uphold the traditional practice for the length of time prescribed. Nevertheless, any deviation from the norm is permitted only following consultation with one's spiritual father or with the prior approval of the local hierarchy.
http://www.goarch.org/ourfaith/ourfaith7070 [Calendar of the Orthodox Archdiocese of America]