In the recent past (say the last 150 years or so), the traditional Advent discipline in the Latin Rite was as follows. As with the rest of the year, all Fridays and Saturdays were days of abstinence from meat. (In the United States Saturday abstinences were dispensed with in 1840 unless that day was also a fasting day) In addition to Friday as a day of abstinence, Fridays in Advent were fasting days as well. The Ember Days, or Quarter Tenses as they were referred to, were days of fast (the Wednesday, Friday, and Saturday immediately following the third Sunday in Advent). Lastly, Christmas Eve itself was observed as a fasting day in preparation for celebrating Christ’s birth. It should also be noted that in keeping with the somber nature of the season, marriages were not solemnized during the Advent and Christmas seasons, and this is still true today.
Current Canon Law of the Latin Rite no longer requires days of fasting during Advent, but does still require that all those who are over the age of 14 to abstain from meat on Fridays throughout the year. In the US, some other serious act of penance may be performed in place of this abstinence. During Advent we are still called to prepare ourselves for Christ’s birth through prayer, penance, fasting and alms giving. So while the old schedule of Advent fasting and abstinence is no longer mandatory, the old discipline is still worth remembering and practicing as a means of preparation. To paraphrase Scripture, what profit is it to have completed one’s shopping list if one has lost the sense of the season?