There are plenty of scripture that point in the direction of a fast. A fast is used to bring focus to my walk and my purpose and it goes well beyond abstaining from food or other items.
Steps to a Fast
1. Pray about the purpose. There should be a reason for a fast that involves increasing a personal and intimate relationship with Christ. Fasting should NEVER be done just to go without food.
2. Plan a replacement. Feed the spirit while you are not feeding the body. Plan to use the time to pray, study, read the word or just talk with Go.
3. Proclaim the fast to God. It is not about showing the fast to man. Matthew 6: 16-18 specifically points to the concept that others do not need to know what you are doing. Fasting is a personal journey.
4. Expect the reward. Understand the word concerning your needs and expect an answer to the prayers. In addition to the answering of prayers, fasting will help guide you to the fruit of the Spirit.
Fasting is a personal journey but you will not be left alone. God sends support to help you along the way. Look at the example of Jesus (Matthew 4:11). The angels will assist you so be on the look out for the blessing and benefits sent by God.