Lembas

Lembas is a type of waybread created by the Elves, and one bite is enough to fill the stomach of a grown man (although Hobbits seem to be an exception). It can currently only be obtained as a very rare drop from Galadhrim Elves, found in chests in treehouses, or purchased from Galadhrim Elf Traders. Eating a piece will restore the entire hunger bar.