Fasting and abstinence are long-standing religious practices, which can be found in many religions. It has always been an important part of the Jewish and Christian spiritual life. Jesus expected His disciples to fast after He had departed from them as we see in the Gospel according to Luke: “The days will come, when the bridegroom is taken away from them, and then they will fast in those days” (Lk. 5:35).
The divine law binds all the Christian faithful to do penance each in his or her own way. However, penitential days are prescribed on which the Christian faithful devote themselves in a special way to prayer, perform works of piety and charity, and deny themselves by fulfilling their own obligations more faithfully and especially observing fast and abstinence, according to the norms of Canon Law (Can. 1249).
The Church has instituted certain forms of penitential practices making it easy for the faithful to fulfill their obligations to do penance. The following Canons provide guidance for Latin Rite Catholics:
Can. 1250 The penitential days and times in the universal Church are every Friday of the whole year and the season of Lent.
Can. 1251 Abstinence from eating meat or some other food according to the prescripts of the conference of bishops is to be observed on every Friday of the year unless a Friday occurs on a day listed as a solemnity. Abstinence and fasting, however, are to be observed on Ash Wednesday and Good Friday. Note: Catholics in the U. S. are not obligated to abstain from meat on Fridays outside of Lent, but if abstinence is not practiced then some other form of penance should be adopted.
Can. 1252 The law of abstinence binds those who have completed their fourteenth year of age. The law of fasting, however, binds all those who have attained their majority (eighteenth birthday) until the beginning of their sixtieth year. Nevertheless, pastors of souls and parents are to take care that minors not bound by the law of fast and abstinence are also educated in a genuine sense of penance.
Can. 1253 The conference of bishops can determine more precisely the observance of fast and abstinence as well as substitute other forms of penance, especially works of charity and exercises of piety, in whole or in part, for abstinence and fast.
In honor of the Passion of our Lord Jesus Christ, Catholics fourteen years of age until death are obligated to abstain from eating meat on Ash Wednesday, Good Friday and the Fridays of Lent. Meat is anything coming from the flesh and organs of mammals and fowl; this also would include soups and gravies made from them. Fish and shellfish are acceptable as are food from amphibians and reptiles.
Catholics from the start of their eighteenth year until their fifty-ninth birthday, which would begin their sixtieth year, are obligated to fast on Ash Wednesday and Good Friday. This means one meal a day with two smaller meals that would not exceed the main meal in quantity. Snacks are not permitted.
Note: Those who are excused from fasting and abstinence besides those outside the age limit are those of unsound mind, the sick and the frail, pregnant or nursing women, manual laborers according to their needs. In addition, guests at a meal who cannot excuse themselves without giving great offense or causing enmity and other situations of moral or physical impossibility.
A person who is to receive the Most Holy Eucharist is to abstain for at least one hour before Holy Communion from any food and drink, except only water and medicine (Can. 919.1).
The elderly, the infirm, and those who care for them can receive the Most Holy Eucharist even if they have eaten something within the preceding hour (Can. 919.3).