Maybe you’re just imagining things and you’re actually eating them? It amazes me how fast I go through all my food, and I sure don’t keep track of how many yogurts I have in the refrigerator.
Even if you have some inventory checklist, you may still be making a mistake and thinking she ate something when you already ate it.
If you think she really is eating the food, and the disparity is that great between you (like she is doing zero groceries, only eating your food, and then lying to your face about it), then you need to confront her.
Otherwise, I never get in people’s faces when they eat my stuff. Food is not something muslims should be fighting over and denying other people to have, IMHO, so if my old roomie would tell me she got hungry over the weekend and ate all my ice cream cuz she couldn’t resist, I would laugh and tell her its totally ok, not a problem.
You never know when the day will come that someone stingy wont give YOU something to eat the day you’re starving.
And honestly, who knows, maybe she has some financial issues, and she can’t buy much food?