The Army solved this decades ago with tape tests. Been a quarter century since I had to take one, but it used to be the ratio of various bodily circumferences. If your stomach to chest ratio or your neck to bicep ratio were reasonable, you were OK regardless of physical weight. It takes perhaps a minute per soldier, as compared to recording weight which takes only seconds, so the simple BMI is still useful as a time saving prescreen. It worked very well decades ago, so an optimist would think the Army still tapes and a pessimist would assume it no longer tapes.

I would imagine if 320 million people are going to be measured for financial punishment purposes, there would be a startup opportunity in some kind of 3-d scanning appliance that could auto-generate circumference measurements.

Of course where money is involved corruption will develop and inevitably there will be clinics where patients are asked politely to measure themselves and record their own numbers, such that the promised savings will never occur.

That is a tiny fraction of the population, essentially irrelevant from a public health policy standpoint.

But do weightlifters live longer than other people with equivalent BMIs?