In the sixth chapter of the book of Matthew, Jesus talks about how we should fast and you will notice fasting is not a suggestion, it is assumed we will all fast. Listen to what is recorded in
Mat 6:16 "And when you fast, do not look gloomy like the hypocrites, for they disfigure their faces that their fasting may be seen by others. Truly, I say to you, they have received their reward.
Mat 6:17 But when you fast, anoint your head and wash your face,
Mat 6:18 that your fasting may not be seen by others but by your Father who is in secret. And your Father who sees in secret will reward you.
In verse 16 Jesus said "when you fast", not if you fast. He then goes on to tell us how we should fast and it is similar to how we are to pray. It is done in private, it is not meant to be a display for your piers to see and to heap praise on you for what you are doing. Fasting is a personal thing between only you and God.
Fasting is a time spent in company with God and is practised for a variety of reasons such as. We may be in a personal crisis and are seeking God's guidance to help us through, or the crisis may be one that involves your family, friends or even the conditions of the entire world. So we pray and fast for God's protection and deliverance. We also fast as a way of repentance and as we seek renewal in our faith, again either personal or involving others. We may have come to a cross road in our lives and are seeking God's guidance as we decide what to do next. Fasting is also a way to humble yourself before God in worship.