The first ten days of the fast for me was a breeze. I had very minor detox symptoms.
I took everyday as a personal challenge and didn't take my eyes off my goal. I figured that the only way I was not going to make my forty days was if I chose to quit. I became very aware of my body and I listened to what it was saying to me all the time.
Keeping hydrated was my biggest challenge. I drank about four liters of water each day. Near the end of the fast I was just getting tired of not tasting anything. I was ready to end the fast and to have something to taste.
I think that my spiritual life, I am a Christian, was enhanced during this experience. My prayer life has never been better. Php 4:13