I can't be sure but whenever I have got an extremly low (<500) amount of lp from quests I've looked again and it was actaully XP.
I got an 89% hunger reduction and in the last world I had to stop doing quests because I couldn't eat fast enough as they were "relieving my stomach" faster than I could eat. I also saved up enough xp to dig my well a bit deeper thanks to quests.