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A Brief Introduction to Fasting

Fasting is a spiritual discipline that was practiced by Jesus and early Christians and that today is practiced in many places around the world today where the Gospel is growing most rapidly. Yet in the Western church, it is largely ignored. Our culture, which is built on self-indulgence, tells us that fasting is unhealthy, that self-denial is falling back into asceticism which promotes a false spirituality, that we do not need to fast since we’re saved by faith—all of which are nothing more than excuses for not following a spiritual discipline that was practiced by Jesus himself and that brings with it unique benefits physically, mentally, and spiritually

Why Fast?

Fasting affects us on a variety of levels.

On the physical level, fasting gives our digestive system a rest. When we are digesting food, the body increases blood flow to the digestive organs to absorb nutrients. Fasting allows that blood flow to be redirected to the brain, and many people report increased mental clarity and focus while fasting.

Fasting also can help us increase in discipline. In college, I regularly did a 36 hour fast from Thursday dinner to Saturday breakfast, and I found that I was far more focused and productive with my time the entire week. The self-control required for habitual fasting had a positive effect on my level of self-control for the rest of my life.

Fasting frees up time for Kingdom work we might not normally engage: Is. 58.6-8.

Fasting is also useful as a tool for personal growth. In Celebration of Discipline, Richard Foster says, “More than any other discipline, fasting reveals the things that control us. This is a wonderful benefit for the true disciple who longs to be transformed into the image of Jesus Christ. We cover up what is inside us with food and other good things, but fasting brings these things to the surface. If pride controls us, it will be revealed almost immediately. David writes, ‘I humbled my soul with fasting” (Ps.69:10). Anger, bitterness, jealousy, strife, fear—if they are within us, they will surface due to fasting. At first we will rationalize our anger because of our hunger; then we realize that we are angry because the spirit of anger is within us. We can rejoice in this knowledge because we know that healing is available through the power of Christ.”

There is a danger, however, in focusing too much on these benefits of fasting. As a spiritual discipline, fasting must be focused on deepening our relationship with God rather than the other benefits that come from the practice. If our primary motivation is anything else, the fast will not accomplish its most important purpose.

Fasting provides an intensive arena for disciplining our souls and bodies—appetites, desires, use of time. It reminds us that our priorities in life are always to be spiritual, and it can help to increase our dependence on the Lord in bringing our bodies into submission to Him. Whenever, during a fast, we are reminded of the material deprivation to which we have submitted, we should rejoice in the Lord, singing and praising Him, so that we enter more deeply into His joy at the very moment we are experiencing the most physical trials. It’s not difficult to see how such discipline could stand us in good stead for additional trials when we are not fasting.

Fasting thus can train our souls away from the materialism and sensualism, which are so characteristic of our day, especially as we experience the benefits of fasting in our spiritual lives. It can be a useful season for reviewing all our disciplines—spiritual, relational, vocational, communal, and provisional—to make sure they are properly focused and in use.

Although we usually think of fasting only in connection with prayer, in Luke 2:37 and Acts 13:2, fasting is associated with worship as well, reminding us that its purpose is to help us to connect with God. Perhaps the main way this happens is through bringing us face to face with our radical dependence on God, which we often can forget. We have so much stuff and so many resources available to us that it is very easy to rely on these things to carry us through difficult times rather than relying on God. By voluntarily stepping away from food, a necessity for us, it reminds us that “Man does not live by bread alone, but by every word that proceeds from the mouth of God.” 

As we learn dependence on God, our power in prayer and our authority over spiritual forces grows as well, which is why fasting is so often linked to prayer. As had been true in Jesus’ life, prayer and fasting were seen by the early church as essential preparation for ministry.

Most importantly, Jesus taught His disciples that fasting is not an “if” but a “whenever,” and so it is a discipline that Jesus expects all of us to engage in at least occasionally. Thus we see the Apostles and early Christians fasting in the book of Acts (13:2-3, 14:23). The Didache, the earliest Christian writing outside the New Testament (and possibly written before the New Testament was completed), has this to say about fasting and prayer:

But let not your fasts be with the hypocrites; for they fast on the second and fifth day of the week; but fast on the fourth day and the Preparation (Friday). Neither pray as the hypocrites; but as the Lord commanded in His Gospel, thus pray: Our Father who art in heaven, hallowed be Your name. Your kingdom come. Your will be done, as in heaven, so on earth. Give us today our daily (needful) bread, and forgive us our debt as we also forgive our debtors. And bring us not into temptation, but deliver us from the evil one (or, evil); for Yours is the power and the glory forever. Pray thrice in the day thus.

Fasting is a discipline that Jesus himself expected us to do and that has been practiced from the earliest days of the church. It carries with it a host of benefits for body, soul, and spirit, including increased dependence on God and spiritual power. Although it is nowhere explicitly commanded, it is a discipline that believers in the Western world should relearn if we want to see God at work in our increasingly secular world.

How to Fast

Scripture lists several approaches to fasting, ranging from abstaining from certain foods to abstaining from both food and drink (including water) for up to three days. Fasts in the Bible last from a single day to up to 40 days.

To put it differently, fasting can take a variety of forms.

Consult with your doctor before engaging in fasting, particularly if you have any medical conditions or are on any medications. You may be able to get away with giving up certain foods, but even in this case it is better to be safe. Minors should also not fast without medical approval and close supervision. 

For those who are starting out on fasting, here are some ideas to help you begin.

  • Get a few verses together such as Job 23:12, Psalm 42:1-2, and Jeremiah 15:16, and fall back on these when the pangs of hunger or thirst begin to whine and nag. Fasting can be an excellent arena within which to meditate on the nature and meaning of the Lord’s Supper
  • Start small. Don’t plan on a 40 day fast consuming water only. You can always work your way up to more rigorous fasts if you feel yourself led to do that.
  • The easiest way to begin is with either a dawn to dusk fast or a 24 hour fast. If you choose the latter, don’t be legalistic about the time; the idea is to go from dinner to dinner without eating. For example, when you finish dinner on Tuesday, you do not eat again until Wednesday dinner. You can extend this to 36 hours, so dinner Tuesday to breakfast Thursday, if you like, but it is probably best to start with the 24 hour fast.
  • You may drink during the day. Juice, broth, coffee, etc., are all OK, or you may choose to do just water or water and tea with nothing in it (i.e. non-caloric drinks). Be aware that you may get headaches from coffee. I do not recommend diet sodas, however, as the artificial sweeteners produce the same insulin response as sugar, which may make your fast considerably more difficult.
  • Vitamins, etc., are fine to take as well if you’d like.
  • If there are medical reasons that prevent you from fasting from food, consider fasting from something else, e.g. electronic media, television, or anything that will help remind you to turn your thoughts to God and of your dependence on him.

You can and should be flexible about how you get started. See how you respond, and adjust from there. Some people will find the 24 or 36 hour water fast very easy; others will barely make it through a 24 hour juice fast. The important point is to start somewhere and adjust as needed. Eventually you will find an approach that you can practice consistently. Once you become habituated to that, you may make additional adjustments as well.

For a good introduction to fasting with a list of additional resources, see IHOP Fasting Guidelines.

A Brief Introduction to Fasting