NATIVITY FAST - (Advent) The Nativity Fast is one of the four Canonical Fasting Seasons in the Church year. This is a joyous fast in anticipation of the Nativity of Christ. That is the reason it is less strict than other fasting periods. The six weeks prior to Christmas (the Nativity of our Lord in the Flesh) is a fasting period that many call Advent. Advent means "coming."
The fast is also called St. Philip's Fast, coming immediately after his feast on November 14.