Unfortunately, lots gets lost in translation. BMI metrics can provide insight such as trends over a long period of time. Engineers call it R&R Gage analysis. If someone consistently uses a tool or method consistently, and it is done many many many times over a long period of time, the “drift” of the measurement will tell you something (is it trending higher, or lower, or plateauing, etc). However, you cannot take the average of all those measurements, nor can you take a single measurement, with confidence.
So, with BMI…we see the trends of certain States in the USA increasing faster than others. This sort of info gives a bit of insight as to what is going on. But, unfortunately, the granularity of that composite map of millions of measurements is impossible to dis aggregate and re-bundle into a single data point or target.