Jesus' statements concerning fasting are simple and straightforward. His disciples will fast (Luke 5:33-35), but He did not specify how long or how often. As Paul amplified in Romans, fasting is an individual concern between us and Jesus Christ, who is our judge.

Fasting of any length should be approached as an all important tool to draw closer to God.

The Bible has only one command regarding fasting: God's people are commanded to fast on the Day of Atonement from sundown to sundown (Leviticus 23:27-32). This meant they were to fast—to go without food and water—for a period of 24 hours.

Interestingly, this fast day is listed among God's spiritual Feast days. To learn about the meaning of the Day of Atonement and its accompanying fasting, read the article "Atonement: Removal of Sin's Cause and Reconciliation to God" in the Bible Study Aid God's Holy Day Plan: The Promise of Hope for All Mankind

Choosing a length

How long we might safely fast depends on our individual health.

In a sense, everyone fasts. When we are in bed asleep, we go without any food or drink. That is fasting. That is why the first meal of the day is called breakfast. However, when people speak of fasting, they usually mean a longer period of time of deliberately choosing not to eat and drink. It can be for a whole day, part of a day or more than a day.

If you've never fasted before, a commitment of a day may be easier to accomplish and will familiarize you with the process. Use that first experience to learn what your body's particular reactions are.

Another option is a partial fast such as that mentioned in Daniel 10:3. Here one takes in only as much food and/or water as necessary to be safe and spends extra time in prayer, Bible study and meditation. This, too, can be very profitable spiritually.

A healthy person who is not perspiring much can go without food and water for about three days before the body begins to be stressed. And a healthy person can go without food for several days if he is drinking water. Thus, the amazingly long 40-day fasts by Moses, Elijah and Jesus Christ (Deuteronomy 9:9; 1 Kings 19:8; Luke 4:2) were possible only by God's supernatural intervention.

The length of time that someone fasts should always be the length that is right for them at the time. Remain flexible. Of course you'll have a goal in mind when you begin, but don't be too inflexible to end the fast should your body signal. Severe pain and discomfort may mean you have attempted too much, too soon.

Those interested in longer-term fasts are advised to break their fast if and when “true hunger” appears. Be careful not to fast too frequently; allow your body sufficient time to rebuild nutritional reserves. We encourage those with health problems to consult a qualified medical practitioner before fasting.

Fasting is highly personal

While a 24-hour period is the most common length for fasting, any amount of time can be chosen, depending on your particular situation.

Remember, fasting is for one's spiritual health, which involves abstaining from food and drink while spending a lot of extra time in prayer and Bible study (Exodus 34:28; Ezra 10:6; Esther 4:16; Acts 9:9).

When deciding how long to fast, consider when the time is right and you can be truly devoted to the process, instead of trying to squeeze them into a too-busy life. Fasting of any length should be approached as an all important tool to draw closer to God.