Fasting can be a wonderful spiritual experience. Believers who never practice fasting and prayer are missing a spiritual discipline that has blessed many throughout the ages.
A person in good health may choose not to eat occasional meals in order to focus on devotion to God. Not only are there spiritual benefits, but some doctors believe that there are also health benefits. The early church found prayer and fasting valuable when seeking the guidance of God for making important decisions such as choosing spiritual leaders; see Acts 13:2-3 and 14:23. God will honor and bless anyone who fasts and prays in the right spirit.
When Jesus fasted (Luke 4:2), we are told He ate nothing. It meant in all probability that He abstained from all food, solid or liquid, but not from water. This type of fast may be called the "normal fast." There are also a few examples in the Bible of the "absolute fast" which means abstaining from drinking water as well as from eating, as in Ezra 10:6. In Esther 4:16, Queen Esther instructs Mordecai, "Fast for me. Do not eat or drink for three days, night or day. I and my maids will fast as you do."
See also Paul's fast in Acts 9:9. Other examples are in Deuteronomy 9:9, Exodus 34:28 and 1 Kings 19:8. This method of fasting is an exceptional measure for an extremely unusual situation. One would need to be very sure of the leading of the Lord to undertake any fast for longer than three days or one which excludes liquid. A doctor's advice would be very important as well.
There is also the "partial fast" which is a restriction on certain foods or certain meals, as in Daniel 10:3 and 1 Kings, chapter 17. This method is used today by some who omit one meal a day and spend that time in prayer. Biblical fasting can be public as well as private, regular as well as occasional, involuntary as well as voluntary. For a detailed discussion on fasting, we suggest the books God's Chosen Fast by Arthur Wallis and Hunger for God by John Piper.