In
NetHack, a
ring of slow digestion will put your natural rate of
food consumption at
zero. Hunger effects from the other
ring you're wearing still apply, as does added hunger from
teleportation, etc. Rings of slow digestion cannot be eaten by anything, and slow
digestion cannot be gained as an
intrinsic.
This is another one of those NetHack items that would be nice to have in real life.
As a side note, I think that "slow digestion" is a misnomer. Digesting food slowly probably wouldn't help much, because nutrients would be absorbed accordingly slowly and you would starve. Slow metabolism or efficient digestion (or even food multiplication) would have been better titles, I think.