That would be Lembas (sindarin tongue) bread! In quenya, i think is coimus. Lembas means’journey’ i believe. it is called waybread in the common tongue. It came from Yavanna, who is an Ainur of the Valar (basically a demi-god in greek equvo-methology). I think its probably a link to the catholic bread thing as Tolkien was catholic.
I’d survive a week maximum haha…