There is power in corporate fasting and power in corporate praise.
The Son of God fasted because He knew there were supernatural things that could only be released that way.
Fasting breaks the spirit of heaviness.
Whatever is stealing your peace and rocking your boat, what ever is taking your smile away, reach down, pick it up, and throw it overboard.
Fasting will also overcome sexual additions and demonic powers.
Many times the rewards of fasting come after the fast, though from time to time answers can come during the fast.