Since apostolic times a period of preparation and fasting has been observed before the Easter festival. It was a time of preparation of candidates for baptism and a time of penance for sinners. In the early centuries fasting rules were strict, as they still are in Eastern churches. One meal a day was allowed in the evening, and meat, fish, eggs, and butter were forbidden. The Eastern church also restricts the use of wine, oil, and dairy products. In the West these fasting rules have gradually been relaxed. The strict law of fasting among Roman Catholics was dispensed during World War II, and only Ash Wednesday and Good Friday are now kept as Lenten fast days. However, the emphasis on penitential practice remains.

In the Anglican churches The Book of Common Prayer prescribes that Lent be observed with fasting. In Lutheran and many other Protestant churches Lent is observed with various services and practices.