B.M.I. is out B.R.I. is in

As you probably know. B.M.I. stands for body mass index, which is the ratio of height to weight. The B.M.I. began as an index developed by Adolph Quetelet (1796–1847), a statistician who studied the distribution of weight in a population—mostly 5,738 Scottish soldiers. It’s been used as a medical screening tool since the 1970s.

I’ve always thought this measurement was problematic. Consider this: Arnold Schwarzenegger, in his prime, was in the “obese” category. So is American Olympic rugby player Ilona Maher. (Muscle weighs more than fat.) A study of 500,000 U.S. adults found that those with a B.M.I. between 25 and 29.9 (“overweight”) had a 5–7% lower risk of death than those with a "healthy" B.M.I. And so forth. For most of my adult life, including now, I’ve been in the “overweight” range.

Because of its obvious shortcomings as a measure of health, it is now being replaced by the B.R.I., the body roundness index. This metric measures how round or circlelike you are to get an estimate of abdominal fat, which is supposedly linked to an increased risk of developing Type 2 diabetes, hypertension, and heart diseases. That’s because fat stored in the abdominal cavity surrounds internal organs such as the liver and contributes to insulin resistance and glucose intolerance as well as high blood pressure and lipid abnormalities.

Apparently, it’s a complicated formula, but you can avoid the math by using a calculator. You’ll need to include more measurements than with a B.M.I. calculator, which looks at only height and weight.

I’m not bothering with it myself. Plus, I’m not sure that I trust this metric either. Just leave me alone.

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