Not just a southern pansy, Sergeant

Aziraphale, although not the most self-aware being in the history of Creation, is self-aware enough to know that he's being petulant¹. He doesn't need to eat, drink, or do any of the things that are generally required to sustain a human body. He's not even supposed to want to do any of those things. The fact that he does is immaterial.

If wishes were horses, et cetera, et cetera. Unfortunately, supposed to has become an increasingly slippery concept throughout the many thousands of years of his existence. And, perhaps even more unfortunately, Aziraphale would go to increasingly un-angelic lengths, at this juncture, for a restaurant-quality meal. Crowley is doing his best, because of course he is², but Aziraphale would really like not to see another packet of crisps or McDonald's cheeseburger anytime soon. Ideally, anytime ever.

Somewhat melancholy, he's sitting in the library and paging through an equally melancholy-looking copy of Ulysses. Reflexively, he's tried to miracle himself a drink, which is why there's an untouched can of Tab balanced on the arm of his chair.

¹Also, it is technically possible to be self-aware about one's lack of self-awareness. There's a delicate balancing act going on here, all right? That's what an angelically expansive mind is for.
²Because Crowley is good, and kind, as skittish as he becomes around those facts.