My girlfriend (22F) keeps gifting me (20M) expensive food that I hate, how do I tell her without letting her down?

Short context, me and my girlfriend are in a distance relationship, we met at a show through a mutual friend and we see each other at least once a month and at holidays, because of that I believe she gets a bit insecure since I'm her first boyfriend and we don't see each other daily so she constantly gifts me things even though I told her she didn't need to, that as long as we can talk everyday it's okay. Sometimes are thing's like a book I wanted, something in a game, I always gift her something along those lines as well and so go on. I live alone in a bit city, and throughout university and work I'm not able to cook everyday, I mentioned to her once that I've eaten noodles all week and since then all her gifts had been food. I am a level 1 autistic guy, kinda picky eater and have a really bad contamination OCD in with have me not eat out on most places. Sometimes I get home with a message of her telling me she ordered from a restaurant whose food Its weird or that I find really a "no zone" and even though I couldn't be happier to have such a caring and thoughtful girlfriend that I love very very much I don't know how to tell her I can't eat those. I tried at first thinking it was an opportunity to grow out of my picky eater era and confront my OCD but it always end up with one bite and me running to the bathroom and eventually giving it to someone else. She's aware of all my eccentric quirks because of our time together and bc I always update her on my therapy, in with I'm very slowly advancing, so I guess she thought it was okay!

I tried giving hints by sending me eating healthy food I cooked for myself or that I'm not eating that bad anymore but it didn't really help.

How do I tell her to stop without looking like an ungrateful piece of shit?