Oh, because it's cold. And even if you're not used to eating or sleeping or drinking, you may end up having to do those things.

I'm not even sure if we can get sick, really.

[ He doesn't want to chance it, but he also just doesn't know. It's very frustrating, having no knowledge of something that you once took for granted. ]

If you don't wish to eat it, I won't be offended.

Did you put all these sigils up yourself?

[ What a dumb question, Aziraphale, who knows that there's exactly two angels and one demon inside this entire town and several witches, but none of them who make these sort of protective staves. Not these specific ones. ]