My husband grew up in a family where the men told the women what's what.
Every blue moon, this weird archaic type neanderthal appears and I'm left wondering what the heck...
I walk away. I won't even engage.
When I do that, he knows he has crossed the line.
Do you have a sign like that - that he can do if you've gone too far? If not, maybe come up with one.
My husband used to smoke. I don't think I mothered him so much as my thing was watching that I didn't nag. His mother nags. So this would have been very annoying to him because he grew up being nagged to death.
What worked for me was just being honest but kind, at an appropriate time. So if you do have concerns, and you will, find a different way to express them. Make them about you - not him. It's all how you word it.
I doubt very much if you're a controlling type of person that you will be able to change that entirely, even with therapy. That's ok. I have a sister we call Monica (off the character in Friends). It is who she is. Your husband married you and loves you, so he knows who you are. This is part of you. Instead, work on delivery. Say "I have a concern ...". Leave it at that. You've voiced your opinion. Try not to do it right when it's happening (deal with it later).
Then let it go. You did what you felt you had to do - which was to mention it. Have him tell you when you've gone too far - so that it does not turn into an argument. Know yourself (work on this) when you're upsetting him. Find a way to leave the room - go somewhere and decompress if you have to.
I have a son who I used to stress over. It was my problem. He was just living his life, his way. I did see a therapist a few times (as did he). I was concerned about him - but too much. My stress added to his stress. So you're not really helping your husband by being concerned about his weight/food. He already is stressed/concerned about his weight and food.
So - take a sec and have a wife-moment, before you speak. I still worry about my son, but I don't voice it. I voice it to my husband, and then I let it go. Over time, I've noticed he can handle life well enough on his own. Your husband will be able to also. Trust him. You can't make a difference either - not really. Even if you want to. Accept that. :)