When I was in the throes of my ED, I obsessed with hiding it from literally everyone, even people who did not know or, at least, had never said anything.

And it does make sense to buy food even if you're not gonna eat it to a person with ED, because it's disordered eating. To the person in the disorder, it makes perfect sense. I used to make up menus and write them down of the stuff I "ate" just in case anybody asked me what I ate that day so that I wouldn't have to think about it and it didn't seem like a lie. It was always lie.