Imagine trying to determine if you are dangerously overweight without ever stepping on the bathroom scale.
That’s what a new method for determining body size aims to do, using a formula that divides height by waist size.
Called body roundness index (BRI), it can reveal how much fat you have inside you, regardless of your build, and is claimed to be a big step up from the raw results provided by body mass index (BMI) tables. used. by doctors for years.
And research suggests that, in addition to being much more precise, the complex mathematical formula behind BRI can also determine how likely this fat is to cause premature death from serious obesity-related conditions, such as heart disease, diabetes and cancer.
The BRI was devised more than a decade ago by US researchers, who were looking for more accurate ways to assess unhealthy weight gain. Dr. Diana Thomas, a mathematician who came up with the new formula, recently told how she looked in the mirror one day and thought, “I’m not a cylinder, I’m more of an egg.” But how can I capture that?’
For decades, doctors have been monitoring health using the BMI chart, which uses weight and height measurements to produce a reading that bluntly indicates whether we are a healthy size, underweight, or obese: a healthy BMI range is between 18 ,5 and 25.
But the system has long been recognized as flawed, as a muscular athlete could be classified as obese simply because muscle is denser than fat.
At the other end of the scale, a thin person with little muscle but a belly – indicating an accumulation of visceral fat – could be classified as healthy.
Visceral fat is the unhealthy type that accumulates around organs, such as the liver, increasing the risk of diseases such as type 2 diabetes and heart disease by disrupting the normal balance of glucose and insulin in the body.
Dr. Diana Thomas, a mathematician who came up with the new formula called Body Roundness Index (BRI), which reveals how much fat you have inside, regardless of your build.
In short, BMI assumes that if your weight is excessive, so will your visceral fat levels.
With BRI, however, you enter your height and waist measurements into the BRI calculator; you can find one online. It then uses a complex formula to produce a score that reflects how thin you are from head to toe or whether you are more rounded in the middle due to visceral fat.
BRI scores range from 1 to 16: Those near the lower end are likely to be underweight and at risk of developing thin bones, infertility, and a weakened immune system.
Those with a score of 3.5 to 7 are likely to be at a healthy weight, with little excess abdominal fat. Anyone with a score above 7 is in the danger zone for obesity and poor health.
BRI attracted interest after a study in the Journal of the American Medical Association Network Open, published in June, found that it accurately predicted which middle-aged men and women were at risk of dying from obesity-related conditions.
Scientists at Peking University studied nearly 33,000 adults who participated in a health study that lasted 20 years. They used the volunteers’ data on height and waist size to calculate each person’s LBBB, before comparing it to deaths from all causes.
The results showed that the risk of dying prematurely among those with the highest BRI was 49 percent higher than those in the lowest range.
And a study published in the journal Lipids in Health and Disease in 2023 showed that LBBB was also a good indicator of who is most likely to develop bowel cancer.
Researchers in China studied more than 53,000 people and found that those with a high BRI score were up to five times more likely to fall victim to the disease than those with a low score.
BMI was originally conceived to advise on public health strategies (not quantify an individual’s health), but it became popular as such in the United States during the 1970s. A 2019 study published in the journal BMJ Open Sport and Exercise Medicine found that many of England’s best rugby players, based on their BMI, qualified as obese.
Tom Sanders, professor of nutrition and dietetics at King’s College London, told Good Health: “Body fat itself is not harmful; what matters is where it is stored.” Subcutaneous fat (just under the skin) on the hips and thighs is virtually harmless.
But Professor Sanders questions whether BRI is a more accurate indicator of health than a tape measure. “The simplest and most robust measure of unhealthy fat is waist circumference,” he says. “This is what the International Diabetes Federation recommends instead of BMI to calculate the risk of type 2 diabetes.”
To measure your waist correctly, exhale, relax your stomach, and place the measuring tape just above your belly button.
The NHS says that any height over 37 inches (94 cm) in men and 31.5 inches (80 cm) in women is considered a high risk of poor health. The threshold is lower in men of African, Caribbean, South Asian, or Chinese origin: about 35.5 inches (90 cm).
An article published earlier this month in Current Problems in Cardiology suggested that both LBBB and BMI may not be as good as waist circumference in predicting who will develop type 2 diabetes.
Mike Lean, professor of human nutrition at the University of Glasgow, says: “Stick to the size that clearly works: waist size.”