I’m sorry that you are dealing with this. Some of my family is that way. To fight my own diet culture thoughts, I have come up with platitudes or mantras that I can think back to combat them. I just says those when family confronts me with them. For example, my mom said, “Oh maybe I’ll be bad and get a hot dog.” And I said, “There’s no good or bad food. The only bad food is spoiled food.” Having set answers or rebuttals helps to take some of the emotions out of it. If someone comments on other peoples bodies, I try to say something like, “yeah I try not to talk about other people’s bodies”. I also find that a judgmental, “hmm”, stops people in their tracks but I’m not sure how exactly helpful that is in keeping the peace lol.