Golden Apple

Golden Apples are the most difficult to obtain, but most beneficial Food item. They are extremely rarely found in Dungeon, Stronghold and Abandoned Mine Shaft chests, though they can also be obtained by crafting a red apple and eight gold blocks together. Eating one heals, and grants enhanced regeneration for 30 seconds, regardless of hunger level. They are considered to be very valuable to players and are often kept as a kind of trophy. When in your inventory, Golden Apples shine purple.

Advantages

 * Golden apples are the only food that can completely refill the player's health, without a full hunger bar.
 * They are also the only food items that cause temporary constant health regeneration that is not dependent on the player's hunger. This is indicated by the line of hearts bobbing up and down in a wave pattern, with each full wave restoring half a heart.

Disadvantages

 * A red apple is required when the player wishes to craft a golden apple by hand. Unfortunately red apples can only be found in Strongholds or by killing Notch in SMP, which makes them difficult to come by.
 * Golden apples have an extremely slim chance of appearing in chests: 1/125 (0.8%).
 * Since each golden apple requires 8 gold blocks, or 72 ingots to craft, they are neither time nor resource efficient to craft as the equivalent amount of gold could yield 3 full sets of Gold Armor, 18 clocks or 72 powered rails, excluding other ingredients.
 * As of the 1.0.0 release health generation is no longer unique to golden apples as the player can brew health generation potions. Not only do potions last longer (0:45) than a golden apple (0:30), they can also be upgraded with redstone and glowdust to either heal the player more rapidly or to have an even longer duration (2:00). Since golden apples are a food they cannot be upgraded, unlike potions.

Pre-Release
As of Minecraft's 1.9 pre-release 2, Golden Apples now have a purple-ish glow when viewed from the player's inventory. Note: The glow effect is not shown when the apple is in the player's hotkey bar, but rather only when they are viewing their inventory, a chest or furnace.

Trivia
If all the gold was used (it is all consumed) the apple would weigh approximately 154.4 metric tonnes or 340393.7 pounds. This would be like carrying a small blue whale.