I guess it's more about intuition - they see when they damage someone immediately and stop doing that (e.g. wrong choice of prescription pills). With nutrition, they don't see the effect and/or don't attribute it to their advice because it takes decades to take effect, so they keep repeating the old advice. Practically all doctors I ever visited acted primarily on their intuition - "I have experience this works so use it".

> I wonder how all of us are not already dead. I guess doctors who understand statistics have more impact than those who do not. That's why.

The reason why is much simpler: in virtually all cases, if you don't bother to see a doctor, you won't die. Doctors aren't killing people at such high rates that most of us should already be dead.

Resiliance of human body!