Waist-to-hip ratioWHR

Waist-to-hip ratio divides the narrowest waist measurement by the widest hip measurement. It describes shape rather than size: whether fat sits centrally around the abdomen or peripherally around the hips and thighs.

It matters because where fat is stored predicts cardiometabolic risk better than how much there is. Central distribution reflects more visceral fat, and large cohort studies — including INTERHEART — have found the ratio to predict heart-attack risk more strongly than BMI does.

In practice the World Health Organization considers risk to rise above roughly 0.90 in men and 0.85 in women, though thresholds vary by population. Measurement technique matters: use a relaxed tape at the end of a normal breath out, at consistent landmarks each time.