There are no direct scriptures about proper or improper fasting foods nor about the duration of a fast. In the Bible, fasting was most often associated with three attitudes of heart. Most prominently, people fasted as part their repentance from sin. When Jonah told the people at Nineveh that God was going to destroy their city because of their sins, they fasted (see Jonah 3:4-10). A second reason to fast may be to seek guidance from God. Consider the example of our Lord Jesus who fasted for 40 days in the wilderness (see Luke 4:2). Saul (before he became the Apostle Paul) also fasted when he was struck blind on his journey to Damascus (Acts 9:9). Finally, fasting was used as an expression of piety. The prophetess Anna fasted frequently (Luke 2:37) as part of her devotion to God. Cornelius, the first gentile convert, fasted and prayed (Acts 10:30), and God honored it by sending the Apostle Peter to proclaim the gospel to him. 

Concluding from the examples of the Bible, fasting is a voluntary expression of the needs of the heart. Therefore, if you are struggling with very serious issues of life and death, fasting may certainly help you. Specifically, fasting helps us to subdue our flesh. Restricting food and drink may aid you to humble yourself before God and to prepare your heart to accept His will over your own will. The matter of honoring God’s will over our own is critical to any fasting prayer request. Even our Lord Jesus in the Garden of Gethsemane prayed, “…O my Father, if it be possible, let this cup pass from me: nevertheless not as I will, but as thou wilt.”

God is a god of love (1 John 4:9). Be comforted because James 4:8 promises, “Draw nigh to God, and he will draw nigh to you. Cleanse your hands, ye sinners; and purify your heart, ye double minded.”