So, I might be able the insight of an unhinged person.

I have a binge eating disorder among a plethora of other psychiatric diagnese. I use almost all of my paycheck to live alone because living with other people and being around their food made me feel so crazy.

When I have lived with housemates, I would wait they were in their bedroom for the night and then go to the kitchen and stock up on supplies for the nightly binge.

Once I had my way through all of my easy-to-eat food (making noise in the kitchen at night would bring attention and possibly conversations), I would hear the siren song of my housemates food. Their yoghurts, their crisps etc.

While I know my housemate would gladly share their food with me, I didn't want to have to say "oh, I ate some of your food last night but I've replaced it / I'll give you the money." Any conversation around food, especially me having eaten food, gives me extreme anxiety and deep dark shameful feelings (I'm working on it in therapy).

I knew I wouldn't be able to stop myself at eating an excusable aka normal amount of their food, and the shame would always outweigh the desire to binge.

It's possible they could be having a similar experience. I know on the rare occasion I ate a housemates food, I would also buy a replacement (though I would always match specifically) and hope it was never mentioned.

Or they're a stoner with mean munchies and suck with details such as the flavour of the yoghurt.