Wow. Do you know my bf? LOL. You have described my situation to a tee and it's kind of cathartic to see it from your point of view.
My bf feels exactly like you do about health, diet, medications, etc. and he almost cannot help himself commenting about it. I also banned him from speaking about it. Well, I can't control what he says, but there are dire consequences for our relationship and it's really affected my mental well-being. It kind of "clicked" with him when I had to literally, logically explain that when he makes comments about food to me it breaks the connection I feel to him, that it makes my love for him die a little every time. That may sound harsh but it's the truth and nothing else I explained was getting through.
I'm certain he doesn't understand what I "hear' when he makes his comments. What I hear is: "you're fat" (I'm not), "I don't love you the way you are", "you're gross", "I'm not attracted to you", etc. When he has insisted on imparting his knowledge about food and health-related issues to me, I feel harassed and controlled. I feel like I'm not good enough the way I am. It's a terrible feeling. I'm worried we won't survive this. We are currently on the outs due to an incident yesterday.
I believe he also feels compelled to share what he believes is his superior and vast knowledge about the subject with me, which incidentally I don't believe everything he claims to know; and he drinks and occasionally smokes! He has told me in the past that he believes if he says things enough I'll eventually learn. What I've told him and he doesn't understand is people, including me, don't always do rational things. In fact, we are often irrational. If I go to McDonalds occasionally, lecturing me isn't going to help because that's not a rational decision. It's because I FEEL LIKE and WANT to eat a crappy hamburger.
I suppose in response to AveApollo, I would say that maybe understanding the effect it has on others and your relationships would help being able to control arguing with others. Of course, this may depend on with whom you are arguing. If it's an acquaintance, that may not be so important to someone.
So, here's the kicker. We are preparing to go on a trip to Germany and Prague in a week. I already told him I'm eating whatever I want and I don't want to hear it. I already, out of respect for his anxiety levels, curb some of my habits when I'm around him but I'm not going to change who I am because of this.
Thanks for sharing, Suzanne. I think it helps me understand a little better the dynamic that is happening between us. Still, sometimes understanding simply isn't enough because the behavior is driving me batty!