How to Fast: The Church's Law and the Saints' Practice
Fasting is the deliberate mortification of the body for the sake of the soul — the subjugation of the flesh to the spirit, the voluntary acceptance of hunger as a participation in Christ's own hunger in the desert and His agony on the Cross.
Fasting is not a diet. It is not a wellness practice borrowed from secular culture and given a religious veneer. Fasting is the deliberate mortification of the body for the sake of the soul — the subjugation of the flesh to the spirit, the voluntary acceptance of hunger as a participation in Christ's own hunger in the desert and His agony on the Cross. The Church has commanded it from the beginning, and the saints exceeded the command as a matter of course.
Modern Catholics have largely abandoned fasting. This is not because the obligation has disappeared; it is because the culture of comfort has made the very idea of voluntary suffering unintelligible. But the obligation remains, and beyond the obligation lies the invitation — the call to do more than the minimum, to take up the cross not only when compelled but when moved by love.
The Current Law
The Church's present discipline on fasting and abstinence is governed by canon law (CIC 1249–1253) and the norms established by national bishops' conferences.
Days of Fast and Abstinence:
- Ash Wednesday — fast and abstinence
- Good Friday — fast and abstinence
Days of Abstinence Only:
- All Fridays of Lent — abstinence from meat
In many countries, the bishops' conference has permitted the substitution of another form of penance for Friday abstinence outside of Lent. In the United States, for example, the obligation of Friday penance remains, but meat abstinence may be replaced with another penitential act. This is widely misunderstood as an abolition of Friday penance. It is not. Every Friday of the year is a day of penance. The question is only what form the penance takes.
What Fasting Means
Fasting, in the Church's precise definition, means this:
One full meal in the course of the day. In addition to the full meal, two smaller collations (lighter meals) are permitted, with the condition that the two collations together do not equal the full meal in quantity. No eating between meals. Liquids — water, coffee, tea, juice — are permitted throughout the day and do not break the fast.
This is stricter than most Catholics realize and far laxer than what the Church demanded for most of her history. But it is the current law, and it binds under pain of sin.
What Abstinence Means
Abstinence is the prohibition of meat — defined as the flesh of warm-blooded animals. This includes beef, pork, poultry, lamb, and game. It does not include fish, shellfish, or other cold-blooded creatures. Eggs, dairy products, and animal fats (such as lard or drippings used in cooking) are also permitted.
The distinction is not arbitrary. It reflects an ancient discipline rooted in the understanding that the flesh of land animals — being closer in nature to human flesh — represents a more substantial indulgence, and its renunciation constitutes a more meaningful sacrifice.
The 1917 Code: The Older Discipline
For context and aspiration, consider what the Church required before the reforms of 1966:
Under the 1917 Code of Canon Law and the norms prevailing before Paul VI's apostolic constitution Paenitemini, the discipline was considerably stricter:
- Every Friday of the year was a day of obligatory abstinence — no exceptions, no substitutions.
- Every day of Lent (excluding Sundays) was a day of fast.
- The Ember Days (four sets of three days each, at the turns of the seasons) were days of fast and abstinence.
- The vigils of major feasts (Christmas, Pentecost, the Assumption, All Saints, and others) were days of fast.
The total number of fasting days in a year under the old discipline could exceed sixty. The current discipline reduces this to two. The difference is not subtle.
No one is obligated to follow the 1917 discipline today. But nothing prevents it. The older norms represent what the Church considered normal for centuries — what Catholics from peasants to kings observed without complaint. Voluntarily adopting some portion of the older discipline is not scrupulosity; it is generosity.
Who Is Bound and Who Is Exempt
Fasting binds all Catholics from the completion of their eighteenth year until the beginning of their sixtieth year (CIC 1252).
Abstinence binds all Catholics from the completion of their fourteenth year for the remainder of their lives (CIC 1252). There is no upper age limit for abstinence.
Exemptions: Those who are ill, pregnant or nursing, engaged in heavy physical labor, or who have a medical condition that makes fasting dangerous are excused. The elderly and the very young are excused. Those in doubt about whether they are excused should consult their confessor.
Exemption from the obligation does not mean exemption from penance. If you cannot fast, do something else — give alms, pray additional prayers, accept your suffering with patience. The Church's intention is not that the exempt do nothing, but that they substitute a penance appropriate to their state.
Why the Saints Exceeded the Minimum
The Church's law sets a floor, not a ceiling. The saints did not stop at the floor.
St. Catherine of Siena survived for extended periods on almost nothing but the Eucharist. St. Francis of Assisi fasted with a severity that left his body broken. The Desert Fathers — Anthony, Pachomius, and their followers — fasted as a way of life, eating once a day or less, breaking bread only after sunset. St. Thomas More wore a hair shirt under his Lord Chancellor's robes. These are not curiosities from an extreme age; they are the normal behavior of souls on fire with the love of God.
The logic is straightforward. The body, wounded by original sin, tends toward excess. The appetites pull the soul away from God. Fasting reasserts the primacy of the spirit over the flesh. It is training — the Greek word askesis, from which we get "asceticism," means exercise. You do not become strong by avoiding effort. You do not subdue concupiscence by indulging it.
Moreover, fasting is reparation. Christ suffered in His body. The Christian who fasts unites his small suffering to the infinite suffering of the Cross, and that union has redemptive value — not as adding to what Christ accomplished, which is complete, but as participating in it, as St. Paul teaches: "I fill up those things that are wanting of the sufferings of Christ, in my flesh, for his body, which is the church" (Col. 1:24).
Begin
If you have never fasted beyond the bare minimum, begin with the Fridays of the year. Abstain from meat every Friday — not as a substitution, but as the ancient practice of the Church. Add the Ember Days if you follow the traditional calendar. Try the Lenten fast on all weekdays of Lent, not only Ash Wednesday and Good Friday.
The hunger will be uncomfortable. That is the point. Offer it. The small suffering of an empty stomach, united to the Cross, is worth more than the comfort of a full one. Fast, and mean it.