What is a good Body Roundness Index (BRI) score?

What the Research Says About BRI

Body Roundness Index has rapidly gained attention since the landmark JAMA Network Open study published in 2024 by Zhang et al., which analyzed 32,995 US adults from NHANES 1999–2018. The study found that BRI follows a U-shaped association with all-cause mortality — meaning both very low and very high BRI values carry increased risk, with the lowest mortality observed at a BRI of approximately 4.5–5.5.

Key findings from recent research:

• Superior to BMI: The JAMA 2024 study demonstrated that BRI consistently outperformed BMI in predicting all-cause mortality across all age groups, genders, and ethnicities. This is because BRI captures where fat is distributed (central vs. peripheral), while BMI only measures total mass.
• Cardiometabolic risk: A 2023 study in Frontiers in Endocrinology found BRI to be strongly correlated with hypertension, diabetes, and metabolic syndrome — even in individuals with normal BMI. Higher BRI was associated with a 2- to 3-fold increase in cardiometabolic risk.
• Trend over time: Analysis of NHANES data shows that average BRI in US adults has increased significantly from 1999 to 2018, mirroring the rise in central obesity. This trend was most pronounced in younger adults and certain ethnic groups, highlighting the growing importance of body shape metrics in public health.
• Comparison with other metrics: While waist circumference is a simpler measure, BRI normalizes waist size to height — making it comparable across people of different body sizes. A tall person with a 90 cm waist has a different body shape than a short person with the same waist measurement; BRI captures this difference.

The BRI formula was originally developed by Thomas et al. (2013) in Diabetes Technology & Therapeutics. It models the body as a 2D ellipse using waist circumference and height — lower values indicate an elongated (thinner) body shape, while higher values indicate a rounder shape. The growing body of evidence since 2013 supports BRI as a valuable addition to clinical assessment, especially for individuals whose BMI falls in the "normal" range but who carry excess abdominal fat.

BRI Score Interpretation and Risk Thresholds

The JAMA 2024 study established a U-shaped relationship between BRI and mortality: both very low and very high scores carry elevated risk, with the safest zone falling between approximately 3 and 6. This U-shape is important — it means that being very lean (very low BRI) carries its own mortality risk, likely reflecting frailty, malnutrition, or wasting disease in some populations. However, for the vast majority of US adults, the concern is high BRI, not low BRI.

The US population average BRI has risen from approximately 4.5 in 1999-2000 to roughly 5.8 in 2017-2018, reflecting the broader trend of increasing central obesity. This means the "average" American adult is now in the moderate-risk zone — which makes knowing your individual score more relevant than ever.

BRI vs BMI, Waist Circumference, and WHtR

No single body measurement tells the full story. Here is how BRI compares to the three most common alternatives:

• BRI vs BMI: BRI's key advantage is that it captures fat distribution. Two people with identical BMI can have completely different body shapes — one carrying weight around the midsection (high BRI, higher risk) and one carrying it more evenly (lower BRI, lower risk). BMI cannot distinguish between these two. The JAMA 2024 study confirmed BRI outperforms BMI for mortality prediction.
• BRI vs waist circumference: Waist circumference is simpler to interpret but has a major limitation — it does not account for height. A 90 cm waist is very different on a 155 cm person vs a 190 cm person. BRI normalizes waist to height, making comparisons across body sizes valid. If you are very tall or very short, BRI will be more accurate than raw waist circumference.
• BRI vs Waist-to-Height Ratio (WHtR): WHtR uses the same inputs (waist and height) but calculates a simple ratio rather than modeling body shape as an ellipse. BRI's geometric model captures the non-linear relationship between waist size, height, and health risk more precisely. In practice, they are highly correlated and both are valid; BRI adds the geometric model that some researchers prefer for its stronger statistical fit to mortality data.

In practice, using BRI plus a waist circumference percentile gives you the most complete picture: BRI tells you your body-shape risk category, and the waist percentile tells you how your absolute waist size compares to the population. For more on this, see our BMI vs BRI comparison guide and waist circumference calculator.

How to Improve Your BRI Score

Because BRI is driven primarily by waist circumference relative to height, the most effective way to lower your score is to reduce abdominal fat. Evidence-based strategies include:

• Dietary changes: Reduce ultra-processed foods, added sugars, and refined carbohydrates — all of which preferentially drive visceral fat accumulation. Increase fiber (30+ g/day), lean protein, and unsaturated fats. The Mediterranean dietary pattern has the strongest evidence for reducing waist circumference.
• Exercise: A combination of aerobic exercise (150+ minutes/week of moderate-intensity activity) and resistance training (2-3 sessions/week) is more effective for reducing waist circumference than either alone. High-intensity interval training (HIIT) shows particular promise for visceral fat reduction.
• Sleep: Consistent short sleep (less than 6 hours per night) is independently associated with higher waist circumference and increased visceral fat. Aim for 7-9 hours per night.
• Stress management: Chronic stress elevates cortisol, which promotes abdominal fat storage. Mindfulness, adequate sleep, and regular exercise all help moderate cortisol levels.
• Track progress: Re-measure your BRI every 4-8 weeks. Waist circumference changes more slowly than weight, so consistency matters more than speed.

For a comprehensive plan, see our guide to reducing waist circumference.

How to Measure for BRI

1. Height: Measure without shoes, stand straight against a wall
2. Waist: Measure at the level of your iliac crest (hip bone)
3. Use a flexible, non-stretchable tape measure
4. Measure at the end of a normal exhale