Comment by sorethescore

BMI is an objectively terrible individual health metric, it's is literally just weight / height². It measures neither body fat nor visceral fat, cannot distinguish muscle from adipose tissue, says nothing about fat distribution, fitness, metabolic health, or organ function, and its interpretation varies with age, sex, ethnicity and body composition.

And these aren't merely hypothetical bodybuilder edge cases. A systematic review found BMI had only ~50% sensitivity for detecting obesity when compared with body-fat reference methods—i.e. it missed roughly half the people classified as obese by adiposity.

More importantly, the 2025 Lancet Commission on clinical obesity explicitly recommended that BMI be used only as a population-level risk surrogate or screening tool, not as an individual measure of health. For individual assessment they recommend actually confirming excess adiposity with waist measurements or direct body-fat measurement.

Which is basically what this study is demonstrating again: where the fat is contains substantially more useful cardiovascular information than the number you get from dividing someone's mass by the square of their height.