Non-believers do not understand why Christians need to fast. Pastor Shane Idleman from Westside Christian Fellowship says Christians do so because they want the Holy Spirit to lead, guide, and convict them.

In an article for Charisma News Idleman writes that it is always the flesh that holds people back from the things of God, so fasting is biblical and is considered a very important spiritual discipline.

When people fast, they starve the flesh but bring spiritual insight and wisdom to themselves. On the other hand, when people cave into the flesh, the Holy Spirit is unable to do the work for them as what God wants.

"When God tells you to fast and you do it, it's going to benefit you," Idleman says. "Some of the physical benefits of fasting are that it helps with aging, it gives you a better attitude, you have better resistance to disease, you sleep better, you change your habits, you have clearer skin, it improves your senses, you have more clarity and more energy, and so on. I don't know of anyone that wouldn't want those things."

There are at least two Biblical examples when it comes to fasting. Daniel fasted for three weeks and refrained from eating luxurious royal food that the king offered. He made a covenant to refuse foods that are forbidden by God, and only ate vegetables and beans. Because he did so, Daniel received heightened spiritual insight, says Idleman.

During His time on earth, Jesus also underwent a 40-day fast, adds the pastor. It wasn't easy, but after enduring the wilderness, the power of the Holy Spirit was stronger than ever within Him.

"You're either disciplining your body, or your body is disciplining you," says Idleman.