Learn to fast and you will learn the way to lay off all sin. It rests and cleans the system. It teaches self-control. With prayer and separation and Bible study it brings spiritual growth and revelation. Appetite is habit craving of food.
Hunger takes place after the body has used up all the excess stored in the body.
This takes weeks, not hours. Appetite pains for a few days. Drink much water, it helps to eliminate waste in system. Sleep and rest more than usual. You are the reason you fast.