Minecraft wiki entry for Defeating_the_ender_dragon, associated text: Golden apples are the most efficient healing item because they provide Absorption, which grants the player 4 temporary health, as well as the Regeneration effect which restores another 4 health over 5 seconds. Beginners should bring a lot of them to avoid dying
Enchanted golden apples provide Absorption IV, which grants the player 16 × 8 temporary health and restore 16 × 8 health over 20 seconds. They are however difficult to find, so save them for an emergency if you found one
Golden carrots are a highly nutritious food, but quite expensive
Cooked porkchops, steak, bread and pumpkin pie are other nutritious foods to bring to the end