Theory/headcannon (tw: eating disorder allegory)
I came up with this last night and literally stayed up thinking about it.
Crowley doesn't like eating because it reminds him of the fall.
Hear me out, so in season one, when he's in the pub and drunk off his ass talking about when he fell, he says "the food hadn't been that good lately", but we never once see him eat food.
My theory is that he used to eat food as an angel but doesn't anymore because it reminds him too much of the fall, like he wants to but just can't bring himself to even have the smallest amount of food. Which is also why he watches Aziraphale eat, like a way to enjoy food without eating it.
This probably makes no sense, but the thought means a lot to me as someone who sometimes struggles with food.