I am a 6’ man and I can say for sure that anything at 185 or so pounds is definitely overweight. I’m at 175 or so right now and trying to cut down on some of my flab.
There have been some recent studies, however, that show that people in the “overweight” category (not obese though) are actually just as healthy if not healthier than “average” BMIers.
So, medical research tends to indicate that if you’re average, or on the lighter side of overweight, you’re not at higher risk for certain diseases. But if your BMI is on the higher side of overweight, and into obese, then you are at a higher risk for certain diseases.
That’s really all there is to it.
That being said, I’ve heard (though I don’t have a cite) that the whole “body types” thing is more or less a myth. There aren’t a lot of different body types that will skew the results of a typical BMI calculation for the vast, vast majority of people. People with a LOT of muscle (you really do have to have a lot) will have a high BMI, but not necessarily be at risk for certain diseases. From what I’ve heard, that’s about it.