What would happen if you didn't have any food for a long time?

Your body relies on food for fuel, and if it receives no fuel, it will shut down. Without food to break down into glucose and feed your body's cells, they would slowly begin to starve. Your body would then begin to break down fat in your body to nourish the cells. When the fat supply is used, it would then begin to break down the muscle tissue in the body. When all reserves are used, the body would completely shut down and the person would die of starvation.