In the Bible, Jesus, Moses (twice), and Elijah all fasted for 40days.
Jesus for 40 days. If God in human flesh fasted, how much more ought we? Matthew 4:2
Moses fasted twice for 40 days-Following his first fast, Moses received the Law. The second was to turn God's wrath away from God's sinful people. Deuteronomy 9:9,18,19
Elijah fasted for 40 days while fleeing in fear from wicked Jezebel, who threatened to have him killed. God gave him comfort, boldness and instructions to go back the way he came and anoint new prophets. 1 Kings 19
Medical testing has been done to see if the human body can handle a fast of 40+ days. All tests have been done unsucessfully. The body can't take a fast of 411 days, it would long be dead. Fasting's real good at the right time, but defidently not on a lifting day!