Prayer and fasting will produce incredible results in your life. It will produce incredible results for this nation, for your city, for your friends, and for your family. Fasting is a restriction of food for a spiritual purpose; however, there are many ways of restricting food and several books on the subject. God will lead you to the one that is appropriate for you. If you have a medical condition that prevents you from fasting, then I am sure God will show you an alternative if you seek Him.