This is my take on fasting;
Our spirit man and our flesh are waring agaist eachother right? And as children of God we obviously want our spirit to reign over our flesh. Well if you think about it, we feed our flesh constantly. Most of us with three meals a day, everyday. Thats feeding our flesh...giving in to what it wants. So when we deprive it of food, we are denying our flesh of the things it wants. I guess a parallel would be like if you lust after something and not give in to your flesh, by doing this your spirit tends to come alive even more because your flesh is being denied. Many people say you get closer to God through fasting, for me its more of a way to focus on my spiritual being and not my carnal being. Theres a post in "testimonies" about fasting that I wrote, you might want to check it out because i dont feel Im doing a very good job explaining this right now. Anyways, I like to fast, it does help a persons spiritual life and finding what works for you is key. I tried to just give up food flat out a couple times and failed miserably. I figured out that you can deny your flesh a bunch without giving up food tatally.