Another player in the game is the insurance companies, which dictate to the doctors which therapies, treatments, and drugs they must push on patients if they want to be able to accept insurance.
The last doctor I was seeing would ask me every time I went in, to take a statin, even though I'd told him many times that I would never take one. And he'd make careful note in his laptop that he suggested and patient refused (CYA).
Regarding the nutritionist's diabetic meal plans, I'll never forget when I was 1st diagnosed and doctor sent me to the office dietitian. She asked me what I planned to eat and I said "Atkins", naively thinking she'd be proud I knew that. haha! She was aghast! No, No, No, Atkins is dangerous. Atkins has killed people (this was 1999). Then she handed me some handouts with sample meals on them, and I swear to God, one of them had "small bag of M&M's" listed under "Lunch".