Food
Food is what a player needs to eat to fill the hunger bar up. Food can be farmed, fished, butchered, foraged, botanized, and cooked.
See hot food cooking for details about cooking various dishes. Cooked food usually provides a player with more nutrition than if the items were eaten raw.
A player will automatically fast when the hunger bar drops between 6%-8%. However, once a player loses its fat reserves/layers it will no longer be able to fast and will enter a state of starvation.
The only option once that happens is to eat or commit suicide...