I agree, cherenkov, but I also think it largely depends on the doctor. Do they treat the weight and its consequences as a statement of fact, or more like the moral failings of an idiot? I have been talked to kindly and matter-of-factly about my weight by some doctors. I appreciate that and it definitely serves as a reminder and motivation to get back on track.
By others, I have been lectured using words and tones like I am unintelligent, or they ignored the weight I HAD lost (apparently 25 lbs in 6 months was not enough to avoid a lecture, though I was there for strep throat), or lectured me about a recent weight gain-- literally 2 weeks after I'd given birth, as compared with my pre-pregnancy weight.
I also have had the hardest time being diagnosed with actual diseases because, since I am fat, all symptoms must only be a result of fatness and will magically go away once the excess weight is gone.
So while I was never one to avoid going to the doctor altogether, I certainly did change doctors a few times.