The elvish food the Fellowship eats on its journey is lembas. Also called waybread, it is a special travelling food made by the Elves of Lothlórien and given to the Fellowship before they leave the forest realm.
Lembas is described as a thin, cake-like bread wrapped in leaves. A single cake could sustain a traveller through a day of demanding travel, making it especially valuable during the Fellowship’s journey toward Mordor. Its nourishing power is presented as partly Elvish craft and partly an almost magical quality.
The Fellowship receives lembas from Galadriel and the people of Lothlórien. The cakes remain edible for a long time when kept in their leaf wrappings, although Sam and Frodo eventually rely on them heavily after entering Mordor.
Waybread is not a separate food: it is another name for lembas. Cram is a dense travel biscuit associated with the Men of Dale, while miruvor is an Elvish cordial rather than a food.