The Catholic Church historically observes the disciplines of fasting and abstinence at various times each year. For Catholics, fasting is the reduction of one's intake of food, while abstinence refers to refraining from something that is good, and not inherently sinful, such as meat. The Catholic Church teaches that all people are obliged by God to perform some penance for their sins, and that these acts of penance are both personal and corporeal. Bodily fasting is meaningless unless it is joined with a spiritual avoidance of sin. Basil of Caesarea gives the following exhortation regarding fasting:Let us fast an acceptable and very pleasing fast to the Lord. True fast is the estrangement from evil, temperance of tongue, abstinence from anger, separation from desires, slander, falsehood and perjury. Privation of these is true fasting.

The 1983 Code of Canon Law, also called the Johanno-Pauline Code, is the "fundamental body of ecclesiastical laws for the Latin Church". It is the second and current comprehensive codification of canonical legislation for the Latin Church of the Catholic Church. The 1983 Code of Canon Law was promulgated on 25 January 1983 by John Paul II and took legal effect on the First Sunday of Advent 1983. It replaced the 1917 Code of Canon Law which had been promulgated by Benedict XV on 27 May 1917.