Professor Jim Mann tells RNZ's Emile Donovan why BMI is still one of the best and simplest screening measures we have for determining our risk of developing several serious health conditions.
Body Mass Index, or BMI, is calculated by taking your weight in kilograms and dividing it by the square of your height in metres. Comparing this value to predetermined categories (which may vary between different populations) gives a good indication of your level of body fat.
BMI can be used to help predict an individual's risk of developing conditions like heart disease and diabetes, when considered alongside other risk factors such as blood pressure, blood glucose and cholesterol levels and cigarette smoking.
Professor Mann explained how BMI is used clinically to determine disease risk and enables people to take steps to prevent developing these diseases. He emphasised that BMI should not be used to stigmatise people but rather as a screening tool to help them avoid conditions like heart disease.
"It is probably the single best tool we've got of identifying ... people who are at risk for what is one of the commonest medical conditions that is associated with a lot of ill health, morbidity and premature mortality, and it shouldn't be dismissed," says Professor Mann.
While BMI may not be predictive for those with pronounced muscular development, such as top-level rugby players, Professor Mann says it is a useful screening tool for the vast majority of the population and stacks up remarkably well when compared with objective measures of body fat composition derived from whole body scans.
Listen to the RNZ interview
Why are we still using BMI if we know its flaws? Nights on RNZ, 14 October 2024