Just watch the commercials on TV or see the food counter. Everything is focused on satisfying our appetite. When you go to the mall, scan the people how many overweight you can find. This are just one of the evidence that appetite is hard to discipline. To deny yourself for food is not a pleasant experience. A friend of mine tried one-day water fast and he didn't last for 24 hours. When the evening came, he wished its morning so he could resume eating. He finally he got up at 11:00 PM and went to the street and look for something to eat. He confessed, it was very hard to go one-day without food.
On the fourth week of February 2011, God impressed in my heart to fast for pure spiritual reasons. There are fours reasons I wanted this fast. First, Personal Holiness, second, Passion for God, third, Providence of God for future Ministry, Fourth, Power for Ministry. These four reasons were very personal. Fasting does not make one more spiritual, although others claim it does. It does not make you more godly. As Christian though, fasting of course is an spiritual discipline that deeply involves the physical realm! I did a 10-day fast.