NPC's that have a low responsibility, that eat, and do not have a respawning food supply in inventory will go out stealing food when their script triggers they should eat. A notable example off the top of my head is City-Swimmer in Bravil.
If they get spotted during a theft attempt, the victim will attack them. Other people may join the fight. This can cause sudden NPC death.
Ive heard many tales about Else God-hater being involved in brawls. Its just one of those things that happen in the wonderful world of radiant AI

Like that time Glarthir attacked his 'spies' even before I started the quest.
I tend to bribe people so they have money to buy food, but I dont even know if it works lol.