A lembas wafer is a kind of comestible. It has the highest Nutrition/Weight ratio of all the comestibles. It is a vegan food. Lembas wafers can tame cats and dogs. Also, it takes only two turns to eat. Therefore, it is a highly recommended food for an ascension kit.
In the morning, as they were beginning to pack their slender
goods, Elves that could speak their tongue came to them and
brought them many gifts of food and clothing for their
journey. The food was mostly in the form of very thin cakes,
made of a meal that was baked a light brown on the outside,
and inside was the colour of cream. Gimli took up one of the
cakes and looked at it with a doubtful eye.
'Cram,' he said under his breath, as he broke off a crisp
corner and nibbled at it. His expression quickly changed,
and he ate all the rest of the cake with relish.
'No more, no more!' cried the Elves laughing. 'You have
eaten enough already for a long day's march.'
'I thought it was only a kind of cram, such as the Dalemen
make for journeys in the wild,' said the Dwarf.
'So it is,' they answered. 'But we call it lembas or
waybread, and it is more strengthening than any foods made by
Men, and it is more pleasant than cram, by all accounts.'