This week begins one of the quarterly periods observed by the Catholic Church called "Ember Days." I remember them growing up. Our Catholic calendar showed a half fish meaning that on those days (Wednesday and Saturday) meat could only be eaten at the main meal. Friday, of course, was a day of complete abstinence. All three days were fast days (one main meal and two smaller meals that did not add up to a full meal).
The purpose of the ember days was to sanctify the coming season. Catholic Answers quotes from the Catholic Encyclopedia describing them this way: