As I have said previously, all of the forty-day fasts recorded in the Bible can be classed as supernatural. We’ve already considered Moses two forty-day fasts in God’s presence. Elijah also fasted for forty days, but he was fed by an angel beforehand (see 1 Kin. 19:5-8). There were also some very supernatural elements to Jesus’ forty-day fast. He was supernaturally led by the Holy Spirit into the wilderness. He experienced supernatural temptations from Satan near the end of His fast. He was also visited by angels at the end of His fast (see Matt. 4:1-11). Forty-day fasts are not the biblical norm.
If a person voluntarily abstains from eating one meal for the purpose of spending time seeking the Lord, he has fasted. The idea that fasts can only be measured in terms of days is erroneous.
The two fasts mentioned in the book of Acts that we have already considered (see Acts 13:1-3; 14:23) were apparently not very long fasts. They may have only been one-meal fasts.
Because fasting is primarily for the purpose of seeking the Lord, my recommendation is that you fast for as long as you need to, until you have gained what you are seeking from God.
Remember, fasting doesn’t force God to talk to you. Fasting can only improve your sensitivity to the Holy Spirit. God is speaking to you whether you fast or not. Our difficulty is sorting out His leading from our own desires.