Is Body Roundness Index More Useful than Body Mass Index?

The body roundness index (BRI) is an emerging metric in the health and fitness world, providing a fresh perspective on assessing body composition and health risks. Unlike traditional measures such as body mass index (BMI), BRI aims to capture a more comprehensive picture of body shape and fat distribution, which are crucial indicators of overall health and mortality risk.

So what exactly is the body roundness index, how does it compare to BMI and why might it play a pivotal role in understanding health outcomes? Read on to find out.

What is the body roundness index?

The body roundness index is a mathematical calculation that estimates an individual’s body shape and fat distribution based on her height and waist circumference. Developed as an alternative to BMI, BRI is designed to provide a more nuanced understanding of health risks associated with excess body fat.

Unlike BMI, which uses weight and height to calculate a general estimate of body fat, BRI considers the waist’s roundness relative to height to account for central obesity, a critical factor in many chronic conditions.

BRI is expressed as a single numerical value, with higher values indicating a greater degree of roundness and, potentially, higher health risks. The formula is accessible and non-invasive, making it a practical tool for both clinical and personal use.

It’s believed the body roundness index was introduced around 2013 in a paper co-authored by researchers from New Jersey, New York, Louisiana and Germany. It’s a calculation that uses height, weight, waist circumference and hip circumference to determine potential health risks.

The number represents a circular shape, typically egg-shaped, cylindrical or round, and it’s based on the concept of eccentricity, which is how narrow (ellipse) or round (circle) something is.

A healthy BRI is typically considered something below 10, with some authorities relaying that a score from 3 to 7 is generally considered a good score. Falling below 3 has been associated with negative health outcomes in some research, and going above 7 and especially over 10 also seems to raise the risk of health issues.

How to calculate

So how do you calculate body roundness index? Here’s the formula:

Waist circumference and height are measured in centimeters (cm). Then, waist circumference is divided by 2𝜋 x height to represent the waist’s proportion relative to the body’s overall height.

Steps to calculate:

1. Measure your waist circumference (in cm) at the level of your belly button.
2. Measure your height (in cm).
3. Plug these values into the formula.

Example calculation:

• Waist circumference = 80 cm
• Height = 170 cm
• Compute:

(Note: If you perform the calculation and your result doesn’t look right, recheck the units and calculations, particularly the square root step.)

Interpretation:

• A higher BRI value indicates more abdominal fat and higher health risks.
• A lower BRI suggests a leaner body shape.

BRI is often used in conjunction with other measures like BMI or waist-to-height ratio for a more comprehensive health assessment.

There are also several body roundness index calculators out there that can do the math for you.

BRI and health

Research has shown that body fat distribution, particularly visceral fat around the abdomen, is a significant predictor of health risks such as cardiovascular disease, type 2 diabetes and metabolic syndrome. Because BRI directly accounts for waist circumference, it offers a more targeted assessment of these risks compared to BMI.

A 2021 study out of China found that BRI is a superior indicator associated with cardiometabolic risk. This cross-sectional study, involving 17,000 participants, suggested that BRI may be more effective than BMI and other indicators in identifying individuals at risk for conditions such as high blood pressure, abnormal cholesterol levels and insulin resistance.

Additionally, a 2024 cohort study published in JAMA Network Open linked higher BRI scores with increased all-cause mortality risk, emphasizing its value in predicting long-term health outcomes.  The study involved 32,995 U.S. and evaluated their BRI and health status from 1999 to 2018.

Over that time, mean BRI increased from 4.8 to 5.62, while there was an increased risk for mortality for individuals with BRI scores both too high and too low. For example, the study found people with body roundness index scores of 6.9 or more had a 49% greater risk for all-cause mortality, and those with BRIs under 3.4 had a 25% greater risk.

The study authors concluded that “the association between BRI and all-cause mortality followed a U-shape, with both lowest and highest BRI groups experiencing significantly increased risk of all-cause mortality.”

Given this groundbreaking research, studies have been conducted and continue to be conducted on how the body roundness index can impact other conditions, including:

• diabetes and prediabetes (BRI could be a predictive marker)
• heart failure (higher BRI associated with increased risk)
• hypertension (appears to be an accurate indicator)
• and more

Body roundness index vs. body mass index

While BMI has long been the standard for assessing body composition, it has notable limitations.

BMI fails to differentiate between muscle mass and fat and does not account for fat distribution. As a result, individuals with high muscle mass may be classified as overweight or obese, while those with excess visceral fat but lower overall weight may be overlooked.

In contrast, BRI provides a more accurate assessment of central obesity, a key factor in many health conditions. For example, a 2024 study compared BMI and BRI in predicting metabolic syndrome and found that BRI was significantly more accurate in identifying individuals at risk.

Is BRI more useful than BMI?

The accuracy of BRI in predicting health outcomes has led many experts to consider it a more effective tool than BMI in certain contexts. While BMI remains valuable for large-scale population studies due to its simplicity, BRI’s focus on fat distribution and body shape makes it particularly useful for individual health assessments.

However, it’s important to note that BRI is not without limitations. It relies on waist circumference measurements, which can be subject to variability based on technique and body positioning.

Additionally, while BRI offers greater specificity in certain areas, it should be used alongside other measures like body fat percentage, blood tests and clinical evaluations for a comprehensive health assessment.

Conclusion

• The body roundness index represents a significant advancement in assessing body composition and health risks, offering a more detailed perspective than BMI.
• Its emphasis on fat distribution makes it a valuable tool for predicting health outcomes related to central obesity.
• However, like any metric, it should be used as part of a broader health evaluation rather than a standalone indicator.
• As research on BRI continues to grow, its potential applications in clinical settings and personal health monitoring may expand, providing individuals and healthcare professionals with a more precise tool to assess and address health risks.
• Whether you’re a fitness enthusiast or a healthcare provider, understanding the strengths and limitations of BRI can help you make more informed decisions about health and wellness.