Minecraft wiki entry for How_to_play, associated text: You must watch your hunger level while adventuring, your hunger level is represented on your HUD with . The hunger level decreases as you explore. Certain activities decrease hunger level at a faster rate, such as sprinting. You can replenish your hunger level by eating food. Some foods are more nourishing than others and fill up more . When you get your hunger level up to maximum, the last food you ate applies a saturation value. Saturation is a hidden number that gives you an extra bonus to your hunger level.