Apple

Red Apples are not currently found in-game, except through an easter egg. Reportedly, they used to be found in dungeon chests. If obtained, they can be eaten for or crafted with gold blocks to create golden apples.

As they are very rare and heal very little health, they are not a reliable source of food. Nor is a golden apple as even though it heals all of your health, a massive amount of gold is needed to craft just one, 72 gold ingots.

Advantages

 * Red Apples are used to make golden apples, which heal

Disadvantages

 * Red Apples are very rare (unless your game is modded), and only heal.

Trivia

 * Notch drops red apples when he dies in SMP.