Guides

Take the waist, check blood pressure, get a fasting panel, test your strength. Those four turn a screening number into a decision.

Four methods, four error profiles. The right one depends on whether you need an absolute number, a regional breakdown or just a reliable trend.

The licensed thresholds are BMI 30, or 27 with at least one weight-related condition. The comorbidity question is asked before the weight question for a reason.

Four classic formulas disagree by up to 5 kg at the same height, and none was designed to define health. A BMI range is the better answer.

A child’s BMI is compared with other children of the same age and sex. The 85th percentile marks overweight and the 95th marks obesity.

At the same BMI, adults of South and East Asian descent carry more body fat and more visceral fat, so cardiometabolic risk begins at a lower index.

Divide your BMI by 25 and you get a number that reads itself: 1.00 is the top of the healthy band, and anything above it is the percentage you are over.

Class I starts at 30, class II at 35, class III at 40. The boundaries exist because risk and treatment eligibility change materially between them.

Seven bands, from under 16 to over 40. Each one describes an average risk across a population, and each one hides a wide spread of individual bodies.

18.5 to 24.9 is the band where large cohorts show the lowest all-cause mortality. It is a population average, and several groups sit outside it in good health.