I can't see doctors measuring your waist when you go in to see them. It seems far too intrusive and humiliating.
I can only remember one doctor commenting on my weight. It was a new cardiologist I saw a year ago. He had never met me before and immediately told me that I was 10 pounds into the "overweight" category and that I needed to do something about it. The assistant told him that I had just lost 40 pounds since I was in there a year ago, and the cardiologist was totally dismissive. He then told me it was likely I had high cholesterol and ordered up a panel, despite me telling him that I have always had excellent levels, which proved to be the case yet again.
Needless to say, I never went back to him.