When the connection between health and weight/bmi was discussed in another thread, I found this. I can’t vouch for the research design, but I thought it was interesting.
“Ethnic Differences in BMI and Disease Risk”, which found
“For every 11 pounds Asians gained during adulthood, they had an 84 percent increase in their risk of type 2 diabetes; Hispanics, blacks, and whites who gained weight also had higher diabetes risks, but again, to a much lesser degree than Asians. Several other studies have found that at the same BMI, Asians have higher risks of hypertension and cardiovascular disease than their white European counterparts, and a higher risk of dying early from cardiovascular disease or any cause”
No easy explanation that I can see, but whatever is happening seems to mean a healthier population, at least physically.