A food ration is the most basic comestible in NetHack. Samurai know them as gunyoki. They provide 800 nutrition when eaten, which is more than enough for most states of hunger. They are also suitable for vegans. Food rations may be thrown at cats or dogs to tame them.
Many roles start out with a number of these:
- Archeologists and Monks start with 3-6
- Barbarians and Valkyries start with 1-2
- Tourists start with a lot of random food, some of which may be food rations
A lembas wafer provides the same nutrition as a food ration, but is much lighter; as of 3.6.1, it may even provide more nutrition or sometimes less, depending on if you are playing an elven or orcish character.
"Gunyoki" might not be a Japanese word in real life. 
The little girl stood on tip-toe and picked one of the nicest
and biggest lunch-boxes, and then she sat down upon the ground
and eagerly opened it. Inside she found, nicely wrapped in
white papers, a ham sandwich, a piece of sponge-cake, a pickle,
a slice of new cheese and an apple. Each thing had a separate
stem, and so had to be picked off the side of the box; but
Dorothy found them all to be delicious, and she ate every bit
of luncheon in the box before she had finished.
[ Ozma of Oz, by L. Frank Baum ]
The samurai's last meal before battle. It was usually made
up of cooked chestnuts, dried seaweed, and sake.