Christian Fasting Rules: When Christians Fast and How to Fast Safely

Yes, Christians fast. Jesus told his disciples what to do “when ye fast” (Matthew 6:16), and churches have kept fast days ever since: Lent, above all Ash Wednesday and Good Friday, and Wednesdays or Fridays through the year. Catholics and Orthodox follow set rules. Many Protestant churches leave fasting to each believer.

Who should not fast without a doctor’s advice?

Talk to your doctor before you go without food if you are pregnant or breastfeeding, if you have diabetes or kidney disease, if you take medicine that must be taken with food, if you are underweight or recovering from surgery or illness, or if you have ever had an eating disorder. Ask a doctor, too, before a child or teenager under 18 fasts, or a frail older person, who becomes dehydrated more easily. Do not attempt a dry fast, with no food or water: Cleveland Clinic warns that it can cause dehydration and kidney problems. Catholic, Orthodox and Methodist guidance all make allowances for the sick.

What does the Bible say about fasting?

In the Bible, to fast is to go without food, and sometimes drink, for a set time, usually while praying, mourning or repenting. The Law of Moses appointed one yearly day when all Israel was to “afflict your souls” (Leviticus 16:29). This was the Day of Atonement.

Other fasts were called when need arose. The tribes of Israel “fasted that day until even” before a battle (Judges 20:26). Ezra proclaimed a fast “to seek of him a right way for us” before a dangerous journey (Ezra 8:21). Nehemiah “fasted, and prayed” when he heard that the wall of Jerusalem was broken down (Nehemiah 1:4), and the people of Nineveh “proclaimed a fast, and put on sackcloth” after Jonah’s warning (Jonah 3:5).

The prophets insisted that hunger alone was not the point. Zechariah asked of fasts kept for seventy years, “did ye at all fast unto me, even to me?” (Zechariah 7:5). Isaiah described the fast God wants:

Is not this the fast that I have chosen? to loose the bands of wickedness, to undo the heavy burdens, and to let the oppressed go free, and that ye break every yoke? Is it not to deal thy bread to the hungry, and that thou bring the poor that are cast out to thy house? (Isaiah 58:6–7)

Jesus fasted “forty days and forty nights” in the wilderness before his ministry began (Matthew 4:2). In the Sermon on the Mount he assumed his followers would fast and told them to do it quietly: “when thou fastest, anoint thine head, and wash thy face; that thou appear not unto men to fast, but unto thy Father which is in secret” (Matthew 6:17–18). Asked why his disciples did not fast, he answered that they would once he was gone: “the days will come, when the bridegroom shall be taken from them, and then shall they fast” (Matthew 9:15).

The first churches did. In Antioch the leaders “fasted and prayed” before sending Barnabas and Saul on their mission (Acts 13:3), and Paul and Barnabas appointed elders after they “had prayed with fasting” (Acts 14:23). Paul lists “fastings often” among the hardships of his work (2 Corinthians 11:27). The King James Version has Jesus say that one kind of demon “can come forth by nothing, but by prayer and fasting” (Mark 9:29). The New International Version, following other manuscripts, reads only “by prayer” and notes that some manuscripts add “and fasting.”

When do Christians fast?

The oldest Christian fast days are Wednesday and Friday. The Didache, a church manual probably written in the second century, says: “let not your fasts be with the hypocrites, for they fast on the second and fifth day of the week. Rather, fast on the fourth day and the Preparation (Friday).” It also asks those about to be baptized to fast for one or two days beforehand.

Today the main season is Lent, the weeks of preparation before Easter. Ash Wednesday and Good Friday are the strictest days in the Western churches. The Orthodox Church keeps three more fasting seasons, before Christmas, before the feast of the Apostles Peter and Paul, and before the Dormition of Mary. Beyond the calendar, Christians fast before a hard decision, in grief and in repentance, as the fasts in the Bible were kept.

Catholic fasting rules

The Code of Canon Law sets the rules for the Latin Catholic Church. Every Friday of the year and the season of Lent are penitential days (canon 1250). Catholics abstain from meat on all Fridays unless a solemnity falls on one, and they both fast and abstain on Ash Wednesday and Good Friday (canon 1251). Abstinence binds from age 14. Fasting binds from age 18 “until the beginning of their sixtieth year” (canon 1252); the US bishops put it as “from age 18 until age 59.” Each bishops’ conference may adjust these rules or substitute other penances, “especially works of charity and exercises of piety” (canon 1253).

In the United States, the bishops explain a fast day this way: one full meal, plus two smaller meals that together do not equal a full meal. Liquids are allowed at any time, but no solid food between meals. Every Friday of Lent is a day of abstinence from meat, which means the flesh of land animals and birds; fish and shellfish are allowed. Outside Lent, the bishops ended the binding Friday abstinence in 1966 and commended other Friday penances, though “we give first place to abstinence from flesh meat.”

The bishops excuse people who are physically or mentally ill, including those with chronic illnesses such as diabetes, and women who are pregnant or nursing. Separate from these days is the fast before Communion: Catholics take no food or drink, “except for only water and medicine,” for at least one hour beforehand, and the elderly, the sick and those who care for them are excused (canon 919).

Orthodox fasting rules

Orthodox fasting is stricter and covers more of the year. The Greek Orthodox Archdiocese of America explains that a fast means no meat, fish, dairy products, olive oil or wine. Shellfish are allowed. Orthodox Christians keep the fast for all of Great Lent, which begins on Clean Monday rather than Ash Wednesday, and for Holy Week. Outside Lent they fast every Wednesday, for the betrayal of Christ, and every Friday, for his crucifixion, except in a few fast-free weeks, such as the week after Easter.

The other fasting seasons are the Nativity Fast, from November 15 to December 24, the Dormition Fast, from August 1 to 14, and the Apostles’ Fast, which ends on June 28 and varies in length with the date of Easter. The Orthodox Church in America adds that wine and olive oil are allowed on Saturdays and Sundays in Lent (except Holy Saturday), and fish on the Annunciation and Palm Sunday. On Good Friday, “those who have the strength” keep a total fast.

The Orthodox Church in America’s guide says the rules are relaxed for anyone elderly or in poor health, and that people should ask their spiritual father when unsure. The Greek Orthodox Archdiocese’s article advises beginners not to start with the strict fast, but to give up meat on the Wednesdays and Fridays of Lent and add more in later years.

How do Protestants fast?

The Reformers kept fasting but rejected the idea that it earns God’s favor. The Lutheran Augsburg Confession (1530) teaches that Christians should train themselves “with bodily restraints,” but “not that we may merit grace.” It adds: “we do not condemn fasting in itself, but the traditions which prescribe certain days and certain meats, with peril of conscience.” Luther’s Small Catechism, speaking of preparation for the Lord’s Supper, calls “fasting and bodily preparation” “a fine outward training,” but says the one truly prepared is the one who believes Christ’s words.

Anglicans kept a calendar. The 1928 American Book of Common Prayer names Ash Wednesday and Good Friday as fasts. It lists the forty days of Lent, the Ember Days and “all the Fridays in the Year” as other days of fasting, when “the Church requires such a measure of abstinence as is more especially suited to extraordinary acts and exercises of devotion.” Christmas Day, the Epiphany and any Friday between them are excepted. The Presbyterian Westminster Confession (1646) treats “solemn fastings” as part of worship for particular occasions, to be kept “in their several times and seasons.”

John Wesley fasted weekly, from Thursday at sundown until he received Communion on Sunday, and the Methodist General Rules name “fasting or abstinence” among the practices all Methodists should keep as they are able. Wesley also warned against extreme fasting and urged people in fragile health not to fast from food. The United Methodist Church today gives no official rule for how to fast, and says a fast may include giving up activities such as television or social media.

What are the types of fast?

A normal fast means going without food for a set time. A partial fast gives up certain foods: Daniel mourned for three weeks and “ate no pleasant bread, neither came flesh nor wine in my mouth” (Daniel 10:3). The modern “Daniel fast” takes its name from this verse and from Daniel 1:12, where he asked for “pulse to eat, and water to drink” for ten days. The Catholic and Orthodox rules are mostly of this kind: they limit meals or kinds of food.

An absolute fast gives up water too. Esther asked the Jews of Shushan to “neither eat nor drink three days, night or day” (Esther 4:16), and Paul “neither did eat nor drink” for three days after his conversion (Acts 9:9). Cleveland Clinic advises against going without water, as noted above. Some Christians also give up something other than food for a time. Paul allows married couples to abstain from sex “for a time, that ye may give yourselves to fasting and prayer” (1 Corinthians 7:5).

Elijah’s forty days are sometimes added to this list, but 1 Kings 19:8 says he “did eat and drink, and went in the strength of that meat forty days and forty nights unto Horeb.”

How long should a Christian fast?

The New Testament sets no length. Fasts in the Bible run from part of a day to forty days, and church rules are measured in days: a Catholic fast day, an Orthodox Wednesday or Friday, a season of Lent. For a first fast, one meal or one day is enough. The United Methodist Church advises checking with a physician before a total fast, with no food and only water, of more than 24 hours.

What time does a Christian fast start and end?

Scripture sets no hour. The fast in Judges 20:26 lasted “until even.” Wesley began his weekly fast on Thursday at sundown. In the strict Orthodox practice for most of Lent, the one weekday meal is eaten in the afternoon after Vespers. A Catholic fast day is measured by its meals, and the fast before Communion begins one hour before receiving. A person fasting privately can choose the hours, for example from one evening meal to the next.

How do you fast as a beginner?

Decide why you are fasting and for how long before you begin, and talk to your doctor first if anything in the safety note above applies to you. Cleveland Clinic advises easing into a fast by eating less for a few days beforehand, cutting back on sugar, planning with your doctor for any medicines, drinking water, and avoiding hard exercise while you are not eating.

Use the time you would have spent eating to pray and read Scripture; in Acts the church “fasted and prayed” together. Keep the fast quiet, as Jesus taught in Matthew 6:17–18. An early Christian book, the Shepherd of Hermas, adds a practice: on a fast day, count what your meals would have cost and “give it to a widow, or an orphan, or to some person in want.” The US Catholic bishops point to the same idea in Catholic Relief Services’ Rice Bowl, where people give the cost of skipped meals to feed the hungry. If you feel ill, eat. In the bishops’ words, “common sense should prevail, and ill persons should not further jeopardize their health by fasting.”

End the fast gently. Cleveland Clinic recommends spreading your calories over the next two meals rather than eating one large meal, to avoid sharp changes in blood sugar and the tiredness that follows a heavy meal.

Related reading

• Bible verses about fasting
• Prayers for breaking a fast
• Is Lent a holy day of obligation?