The Tavern

How do you save your permafood? Often, I kill a monster, and get its chunks. However, I am not hungry at that time. Then, the chunks rot, and I become hungry after that. What should I do?

It's usually completely okay to walk around while Hungry/Very Hungry. Hungry doesn't prevent your character from doing anything, Very Hungry only means you can't Berserk, Near Starving is kinda bad because you're close to Starving and getting that in combat is not very good.

Permafood is also usually pretty common.

you get used to the food clock after a while too. Trick is just to butcher the next corpse and eat it once you get hungry - as sar says, you have some time (provided you aren't repeatedly casting high hunger spells)

Also, unless you are animating the corpses or using them in some other way (Fedhas?), just chop every corpse you see. Ever since most gods don't care about corpse sacrifices, there is no downside to that, except for waste of time but that's not really significant if you are not speedrunning.