The problem with BMI alone
BMI treats a 5'8" person with 30 lbs of belly fat the same as a 5'8" person with the same weight distributed evenly. Central (visceral) fat drives most of the cardiovascular and metabolic risk — evenly distributed fat is less dangerous.
That's why some "normal BMI" adults still have high risk ("skinny fat"), and some "overweight BMI" athletes have almost none.
What WHtR adds
It uses one extra measurement — your waist — and compares it to your height. Under 0.5 is healthy across most adults.
A 2020 meta-analysis of over 300,000 adults found WHtR predicted diabetes and cardiovascular death more accurately than BMI.
Use both. BMI for the weight target, WHtR for the shape check.
