Who's a naughty waughty?

I've always wondered about supernatural creatures. I mean like Vampires. Do they ever get indigestion from all that blood? Cause I mean none of their organs work so how do they digest it exactly? And do any suffer from high Cholesterol? And Zombies, sure brains are nice but what about some chips now and then? If they just eat to live (or exist as they're sort of not living) surely a few would raid the veggie patch at night? And how do you house train a werewolf?