Basically, I've tried to consume a corpse to restore some HP after bashing my health away against a door, but it seems Shark Fangs lied to me. You do need stamina higher than 0 to eat corpses, even though the passive says 'it no longer uses stamina'.
I don't know if this is intentional or not, but 'no longer using stamina' from this passive should void not having stamina to eat corpses.