A Biblical & Practical Guide to Fasting

By Allen Reger


Explanation of Fasting

Definition: Fasting is a Christian’s voluntary, deliberate, and generally prolonged abstention from eating (and sometimes drinking) for spiritual purposes. (Sources: Whitney; Eerdman’s Bible Dictionary)

Types of Fasts:

  1. Supernatural: no food or water for longer periods of time than the body can naturally withstand
  2. Absolute: no food or water, but for periods of time the body can naturally withstand
  3. Normal: abstaining from food, but not water
  4. Partial: limitation to certain types or quantities of food

Extent of Fasts: Fasts may be regular or occasional, individual or corporate, and any combination thereof.

Length of Fasts: The Bible mentions fasts that are of unspecified length, partial or one day, 3-day, 7-day, 14-day, 21-day, and 40-day fasts.

Fasting is NOT dieting; about you; a means of manipulating God; an end in itself—to holiness, humility, or self-control; penitence or self-punishment; or required religious ritual.

Reasons for Fasting

Biblical Reasons: Nowhere in Scripture is fasting explicitly commanded. However, it is an assumed practice in Scripture, being mentioned in 59 contexts with the words appearing nearly 80 times. Further, fasting is a discipline that Jesus assumed His disciples would practice and about which He taught them (Matt. 6:16-18; 9:14-15). As a Jew, Jesus Himself practiced fasting (Matt. 4:1-2; Luke 4:1-2). The NT church also fasted on occasion, as we see in Acts 13:1-3 and 24:13.

Historical Reasons: After the NT era, the early church fathers practiced fasting regularly, usually on Wednesdays and Fridays. Christian tradition has been to fast during the Lenten season and, in some traditions, during the Advent season.

Practical Reasons: Fasting is good for a person, both spiritually and physically. Spiritual benefits include a strong communion with God through His word and prayer, clarity in hearing from God, a reminder of our dependence on God, identification of sin in our lives, and an identification with the truly poor and needy. Physically, fasting can provide a cleansing of bodily toxins, higher energy levels, a better sleep schedule and quality, mental focus, emotional stability, and weight loss.

Purposes of Fasting

There are many Biblical purposes of fasting. They are difficult to categorize and isolate because they are usually interrelated. Fasting is beneficial all around and may accomplish many purposes. An examination of Scripture will yield the following general purposes for fasting.

  1. Fasting is an aid to prayer. Prayer is almost always tied to fasting in Scripture. However, not all prayer mandates fasting. Said another way, all fasting involves prayer, but not all prayer involves fasting. Jer. 14:12 indicates that one should pray while they fast. The point of fasting is to earnestly seek God, which we do through prayer.

Fasting seems to be given to “strengthen prayer.” This does not mean fasting manipulates God or makes Him more likely to answer our prayers. Rather, it strengthens prayer for us; it affects us by intensifying our prayers, focus, and devotion. It demonstrates to God the seriousness with which we view the circumstances, humbles us to realize our absolute dependence upon God in all things, and can serve to purify our lives before God.

  1. Fasting is an expression of mourning. Fasting is most commonly used in Scripture to express grief or sorrow for various reasons. In fact, this is probably fasting’s most natural cause and response to grief. When tragedy hits, involuntary fasting usually follows the bad news, forcing us to re-prioritize. Isa. 58:5 indicates the general purpose of fasting is to humble ourselves and mourn before God. Various reasons may be given for this expression of mourning, including intercession, personal sorrow, death of a loved one, sin (either personal or others), present or impending calamity, or a burdensome word or task from God.
  1. Fasting is an expression of repentance and seeking forgiveness. While fasting in itself is not repentance, nor a penitential act to secure forgiveness, it can be an expression of humility and genuine sorrow before God, especially when coupled with prayer for strength to overcome sin. It is crucial to remember that Christians’ sins are fully and only cleansed by the atoning death of Jesus Christ. However fasting can be a time of confession and cleansing (1 Jn. 1:9) to restore us to right fellowship and effectiveness before God.
  1. Fasting is an expression of worship and devotion. Fasting can be undertaken as an act of pure devotion to and worship of God by both individuals and groups of worshipers. Anna served the in the temple by fasting and praying (Luke 2:37). Similarly, in the OT the Jewish fasts were corporate fasts (Est. 9:31; Zech. 7:5), and in the NT the early church was “ministering to the Lord and fasting” (Acts 13:2).
  1. Fasting is a means of seeking God’s guidance and help. At times God’s people need special guidance from Him. Of course, Scripture is God’s full and final revelation to His people containing His will, but the Spirit can illuminate that unchanging truth by convicting our hearts in special ways. Often in the OT, Israel would fast and pray to seek guidance from God as to what they should do in a given situation (e.g. Judges 20:18-28). Some decisions and situations in life can be especially crucial and challenging; during those times we sense strongly the need for God’s help to succeed, protection, or blessing. A way to express that dependence is through fasting and praying. Ezra fasted for the safe return of the exiles (Ez. 8:21ff.) and Esther and Nehemiah fasted to ask God’s favor with the king (Est. 4; Neh. 1:4-11).
  1. Fasting is a means of preparation for ministry. Ministry is a serious task and should be entered accordingly. In Scripture we see examples of fasting accompanying ministry from start to finish, such as preparing to hear the word of God (Jer. 36:9-10), Jesus’ preparation for the work of God (Matt. 4:1-2), special consecration to the work of God (Acts 13:1-3; 14:23), and maintaining purity in doing the work of God (1 Ki 13:8).

Kent Burghuis sums it up well: “The Bible describes fasting as a natural way for God’s people as individuals or as a body to express humility, sorrow, repentance, seriousness in prayer, and a desire for God’s manifest presence.”

Practical Advice for Fasting

There are no set rules for fasting. You should follow the leading of the Holy Spirit in deciding about your fast, such as when, why, what type, and how long. Even so, fasting is both a spiritual and physical discipline and thus requires much preparation.

Health Considerations: It is wise to consult a physician first, especially if you have a known condition or are on medication or before any extended fast.

Some people should never fast without medical supervision, such as those who suffer from eating disorders, anemia, cancer, blood or heart disease, diabetes or blood sugar problems, chronic systemic problems, or those who are pregnant or nursing.

Beginning a Fast: Be sure to start slowly, especially if you are new to fasting. Eat smaller meals two days prior to commencing the fast. Eat raw fruits and vegetables and avoid fatty, sugary, or caffeinated products. Spiritually speaking, never enter a fast hastily, but prayerfully and with certainty. You need to pray and think through your objectives for fasting and determine what type of fast you will undertake and for how long. Set spiritual goals, an agenda, and perhaps even a schedule to keep you on track. Determine what types of social and physical activities you will restrict. Before or as you begin, enter a time of searching your heart and confession to the Lord of all known sin; you should also seek forgiveness and reconciliation with estranged parties. Pray expectantly for the Lord to work and also for strength to persevere and overcome temptations and trials.

What to Do During a Fast: Especially for extended fasts, you should moderate your physical activity (lighten your workload, get plenty of rest, moderate exercise). Fasts much more than 36 hours should have some sort of nutritional intake; natural vegetable and/or fruit juices or even broths are sufficient. You should avoid gum, mints, and caffeine. Remember that fasting is for spiritual purposes, so make that the focus. Some suggested activities during your fast include prayer, reading, memorizing, and meditating on Scripture, reading other devotional books, journaling, evangelism, and singing songs of worship and praise (or simply listening to worship music). Temptations and sin will still come, so repent and confess every instance of sin immediately. Avoid areas of temptation and distraction that will dampen your spiritual focus and draw your heart away (common ones include television, certain social settings, and maybe even certain people). Don’t waste your extra time and waning energy on errands or truly insignificant matters. If done with pure motives, there is nothing wrong with sharing your fast with close Christian friends who can help you, but sharing with most other people is not wise.

What to Expect During a Fast: You should definitely expect God to work in your life (Jer. 29:13; Heb. 11:6; James 4:8). You should also expect increased opposition by your flesh, the world, the devil, and even other people. These difficulties will be magnified by the physical side effects. Common ones include fatigue, headaches, nausea, hunger pangs, difficulty in thought and speech, irritability, bodily aches, digestive changes (such as diarrhea or constipation), and increased urinary activity.

Ending a Fast: Ending a fast rightly is crucial for your health. You must end any fast slowly, especially extended fasts, usually over a period of at least two days. Do not eat solid foods or any animal products to break the fast. Begin by eating several small snacks of fruits or vegetables per day, graduating to such solid foods as salads and soups prior to fully resuming your diet and exercise.


“Your Personal Guide to Fasting and Prayer”

“7 Basic Steps to Successful Fasting and Prayer”

Whitney, Donald S. Spiritual Disciplines for the Christian Life. Colorado Springs: NavPress, 1991. Pages 159-80.

Piper, John. A Hunger for God: Desiring God Through Fasting and Prayer. Wheaton, IL: Crossway Books, 1997.

Berghuis, Kent D. Christian Fasting: A Theological Approach. N.p.: Biblical Studies Press and Kent D. Burghuis, 2007.