What Is Christian Fasting? (The History and Purpose, Plain English)

If you’ve heard about fasting but never quite understood what it is or why Christians do it, this post is for you. The big-picture version: history, theology, purpose. For the practical “how to actually do one,” see how to fast and pray.

The biblical foundation

Fasting appears throughout scripture. Some highlights:

Old Testament. Moses fasted 40 days on Sinai (Exodus 34:28). David fasted multiple times — when his son was sick, in repentance, in mourning. Daniel did a 21-day partial fast (Daniel 10) and saw a major revelation. Esther asked the Jewish people to fast for three days before she approached the king (Esther 4:16). The prophets fasted in calling Israel to repentance.

Jesus. Began his ministry with a 40-day fast in the wilderness (Matthew 4:1–11). Taught his disciples about fasting in Matthew 6, assuming they would do it (“when you fast”). Said his disciples didn’t fast while he was with them, but would fast after he was gone (Matthew 9:14–15).

Early church. Fasted regularly. Acts 13:1–3 describes the church at Antioch fasting before sending out Paul and Barnabas. Acts 14:23 — Paul appoints elders “with prayer and fasting.” The early church document the Didache (~ 90–110 AD) instructs Christians to fast Wednesdays and Fridays.

The biblical and historical witness is consistent: Christian fasting is a normal, expected part of the spiritual life. Not constant. Not extreme. But normal.

The 2,000-year tradition

Christian fasting has been practiced continuously since the apostles. Some highlights:

The first centuries. Wednesday and Friday fasts (commemorating Christ’s betrayal and crucifixion) became standard. The early church combined fasting with extra prayer and almsgiving — a three-fold rhythm of physical, spiritual, and practical discipline.

Lent. By the 4th century, the 40-day fast leading up to Easter was a universal practice. It still is for most Catholic, Orthodox, Anglican, and Lutheran Christians. Increasingly, non-denominational and other Protestants are recovering it.

The medieval church. Fasting was structured throughout the year — Advent fasts, Lent fasts, Wednesday and Friday fasts, vigils before major feasts. Some of this got distorted into legalism, but the practice itself remained meaningful.

The Reformation. Protestants pushed back against forced fasting and external requirements. The pendulum swung — and in some Protestant traditions, fasting nearly disappeared.

Modern recovery. Over the past 50 years, many Protestant traditions have rediscovered fasting as a personal and corporate discipline. Pentecostal and Charismatic streams kept it alive through revival traditions. Reformed and evangelical traditions are recovering it through writers like Richard Foster (Celebration of Discipline), John Piper, and Bill Bright.

If you fast, you join a 2,000-year unbroken line of Christians doing the same thing for the same reasons.

Why Christians fast

Five biblical reasons:

1. To intensify prayer

Some prayer requires more than ordinary attention. Fasting clears the noise — both physical and spiritual — so you can pray more focused, sustained prayer. When the disciples couldn’t drive out a particular demon, Jesus said “this kind comes out only by prayer and fasting” (Mark 9:29 in some manuscripts). Some seasons of intercession warrant fasting alongside prayer.

2. To seek God’s guidance

Major decisions in the Bible are often preceded by fasting. The church fasted before commissioning Paul and Barnabas (Acts 13:2–3). Esther fasted before approaching the king. Ezra fasted before a dangerous journey (Ezra 8:21). Fasting creates spiritual focus when you need clear direction.

3. To express grief or repentance

Throughout the Old Testament, fasting accompanies mourning and repentance. David fasted when his son was sick. Israel fasted in national repentance. Joel called the nation to a fast in a time of crisis. Fasting embodies sorrow in ways that words alone cannot.

4. To break unhealthy patterns

Fasting reveals what controls you. Most modern Westerners can’t go four hours without food, distraction, comfort. The fast surfaces those dependencies and offers a chance to reorder them. Many people who fast for the first time discover their relationship with food (or screens, or comfort) was less healthy than they realized.

5. To wait on God in seasons of transition

When you don’t know what to do — vocation, relationship, ministry, major change — fasting creates a posture of waiting and listening. You’re not necessarily asking God for an answer. You’re making yourself available to receive one.

What fasting is NOT

A few corrections:

Not earning God’s favor. You can’t make God do what you want by suffering more. Isaiah 58 is the classic correction — God rejects fasts that are pure show. The favor is already given through Christ.

Not weight loss. Fasting may have physical effects, but if your motive is health rather than spiritual focus, you’re dieting, not fasting. Both can be good. They’re not the same.

Not asceticism for its own sake. Some traditions throughout history slid into “the more you suffer, the holier you are.” That’s not biblical. Fasting is a tool for relationship with God, not a measure of spiritual rank.

Not for show. Jesus is direct: don’t broadcast your fasting (Matthew 6:16–18). The fast is between you and God.

Not a magic spell. Fasting doesn’t unlock guaranteed answers from God. It positions you to receive what he’s giving — but he gives in his own way and timing.

What fasting does to a soul (over time)

If you fast regularly — say, once a week for a year — here’s what most people report:

Increased awareness of dependence. You realize how much you’ve been using food (and other comforts) to manage emotions, fill time, escape boredom. The discipline brings into awareness what was operating unconsciously.

Sharper prayer. Prayer during fasts is often qualitatively different — more attentive, less performative.

Greater patience. People who can wait through hunger develop a different relationship with all kinds of waiting.

More compassion for the poor. Voluntary hunger creates real empathy with involuntary hunger. Many fasters become more generous.

Reordered appetites. Food, comfort, distraction, attention — all become a little quieter. The desire for God grows in the space those used to fill.

These don’t happen overnight. They develop over months and years of practice. But they do develop.

Where to start

If this post has made you curious, three concrete steps:

1. Read our practical guide on how to fast and pray. That’s the “how.”

2. Skip one meal this week. Just one. Use the time to pray. See what happens.

3. Add a partner. Tell your spouse or a small group friend you’re going to try this. Accountability accelerates the practice.

You don’t have to start with a 40-day fast. The Bible never asked you to. Start small, build slowly, let the practice form you.

What’s next

• How to fast and pray (the practical guide).
• How to pray (beginner’s guide).
• Does God answer prayer?
• Find a life group that fasts together a few times a year.

Christian fasting isn’t medieval. It isn’t extreme. It’s a 2,000-year practice that has shaped millions of believers — and is still available to you. Try one meal this week.