Body Roundness Index: What is it, How to measure and Benefits

For long, we have relied on the Body Mass Index or BMI to know about our health risks. It takes a person’s height and weight into account for predicting their health risks. But now the Body Roundness Index or BRI, developed in 2013, is gaining prominence. It has been dubbed as a better way of predicting a person’s health risk, as it does not just focus on height and weight of an individual. This approach incorporates the waist circumference, so it may be a better indicator of health risks, especially related to obesity. So, should you skip BMI and go for the Body Roundness Index to know more about your health?

What is the Body Roundness Index?

The Body Roundness Index (BRI) is a metric developed by mathematician Diana Thomas in 2013, as per research published in the Medicine journal in 2016. It is a way to assess body shape and fat distribution. “The BRI incorporates the waist circumference, allowing for a comprehensive evaluation of body fat and its distribution across the body,” says bariatric surgeon Dr Vikas Kapur.

It focuses on the roundness of the body and is thought to be a better indicator of health risks, especially connected to obesity, because it accounts for both the amount and the location of body fat. It may also tell you more about your heart health. A new research, published in the Journal of the American Heart Association in September 2024, found that having a high BRI during a six-year duration was associated with up to 163 percent of increased risk of cardiovascular disease.

“Visceral fat, which is associated with higher waist circumferences, is especially dangerous, as it increases the risk of heart disease, diabetes, and other metabolic disorders,” says Dr Kapur. So, a high BRI signals a higher likelihood of developing such conditions.

How to calculate BRI?

BRI is calculated using a mathematical formula that includes both height and waist circumference. Waist circumference and height are both measured in meters.

The result gives a number representing how “round” or “circular” a person’s body is, with a higher BRI corresponding to a rounder, more apple-shaped body. The normal or healthy range for BRI can vary, but a BRI below 4 usually indicates undernourishment. “A BRI between 4 and 9 is usually considered healthy,” says the expert. A BRI above 9 may signal overweight or obesity, with values over 10 being associated with increased health risks.

Is BRI better than BMI?

BRI might be a more accurate measurement than Body Mass Index for predicting health risks related to weight, according to a study published by JAMA Network Open in June 2024.

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“BRI is believed to be a more reliable predictor of health risks compared to BMI, mainly because it takes into account where fat is stored,” says Dr Kapur. BMI has been widely used for decades to classify people into categories such as underweight, normal weight, overweight, and obese. However, BMI’s simplicity is also its major limitation. It does not distinguish between muscle mass and fat mass, and also does not address the distribution of fat on the body.

For instance, an athlete or fitness enthusiast with significant muscle mass may have a high BMI, classifying them as overweight or obese, even though their body fat is low and their health risk is minimal. Conversely, someone with a normal BMI could carry a large amount of visceral fat, increasing their risk for diseases, but BMI would not detect this.

“BRI, by incorporating waist circumference, provides a more accurate representation of fat distribution, particularly abdominal fat, which is a critical indicator of metabolic health,” says the expert. Central obesity, characterised by fat around the abdomen, is often linked to chronic conditions such as cardiovascular disease, and diabetes. This makes BRI a better tool for identifying individuals at risk for these conditions.

Despite this, BMI is still useful for its simplicity and ease of use. It remains a quick and practical method for assessing general population health and weight trends. BRI, on the other hand, is a more specific tool, requiring more precise measurements and calculations.

What are the limitations of BRI?

BRI may be considered a more accurate predictor of health risks than BMI, but it has limitations.

1. Complexity in measurement

The BRI formula is more complicated than BMI, which is simply weight divided by height squared. BRI requires accurate waist circumference measurements, which can be difficult to obtain consistently. Improper measuring techniques, such as measuring the wrong part of the waist, can lead to inaccurate results. Also, the calculation itself is more complex, potentially limiting its widespread use compared to BMI.

2. Limited consideration of other factors

Although BRI is better at predicting health risks related to obesity and body shape, it still doesn’t take into account factors such as bone density, and individual metabolic rates. “BRI is just a general indicator, and health risks of a person can vary depending on their lifestyle and genes,” says the expert.

3. Not a diagnostic tool

BRI is a screening tool rather than a diagnostic one. It can help identify potential health risks, but it should not be used as the sole determinant of an individual’s health status. Doctors still need to consider BRI along with other factors such as blood tests, family history, and physical activity levels while assessing a person’s overall health.

The Body Roundness Index or BRI is an advancement in understanding how body shape and fat distribution impact health risks, particularly concerning central obesity. It offers a more refined assessment compared to the traditional BMI, which only considers height and weight. While BRI is a valuable tool, it still has its limitations, including the complexity of measurement.