What Is Body Roundness Index and Why It Matters for Liver Health
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When it comes to predicting disease risk, many people are familiar with BMI (Body Mass Index). But BMI doesn't tell the whole story—especially when it comes to fat stored around the organs, known as visceral fat. A new body shape measure, called the Body Roundness Index (BRI), may offer a clearer picture. And it could help identify people at risk for a silent but serious liver condition: Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD).
Understanding MASLD: A Common but Overlooked Liver Condition
MASLD is a new name for what was once widely known as non-alcoholic fatty liver disease (NAFLD). It happens when fat builds up in the liver in people who don’t drink much alcohol—but have other metabolic issues like high blood pressure, abnormal cholesterol, or insulin resistance. MASLD affects nearly 1 in 3 adults globally and can lead to liver scarring, cirrhosis, or even cancer over time.
Interestingly, MASLD doesn’t only affect people who are obese. Many people with a normal BMI can still have dangerous levels of visceral fat and be at risk for liver disease. That’s why researchers are exploring new ways to measure body fat distribution—and BRI is one of them.
What Is the Body Roundness Index (BRI)?
BRI is a number calculated using waist circumference and height. Unlike BMI, which only uses height and weight, BRI captures how “round” your body is—especially around the middle, where harmful fat tends to gather.
Higher BRI values usually mean more visceral fat, which is closely linked to metabolic problems and liver disease. While BRI isn’t commonly used in clinics yet, it’s being studied as a better alternative to BMI for detecting early signs of diseases like MASLD.
The Study: What Researchers Found
The new study examined over 15,000 non-diabetic Japanese adults who took part in long-term health screenings. None of the participants had diabetes, and all had undergone imaging to check for fat in the liver.
Here’s what the researchers discovered:
- About 14.5% of participants had MASLD—even though they didn’t have diabetes or obvious obesity.
- People with a higher BRI had a much greater risk of having MASLD.
- The relationship between BRI and MASLD wasn’t linear—it had a tipping point around a BRI value of 3.06. Below this level, the risk of MASLD rose sharply with even small increases in BRI. Beyond this point, the risk still rose, but more slowly.
- The strongest link between BRI and MASLD was seen in people with a BMI under 24—that is, people who were not technically overweight.
This suggests that BRI may be particularly useful in spotting “hidden” metabolic risks in people who look healthy on the outside but are carrying harmful fat inside.
Why This Matters: A Better Way to Catch Liver Disease Early
The big takeaway? You don’t have to be obese to be at risk for liver disease. People with normal BMI can still have MASLD—especially if they have a high BRI.
This matters because MASLD often has no symptoms at first, but can do serious damage over time. Early detection is key, and using BRI may help doctors spot at-risk individuals who would otherwise go unnoticed.
It’s also a reminder that fat around your waist is more dangerous than fat elsewhere in the body. Monitoring waist size, along with weight, may give a clearer picture of your overall health risk.
What You Can Do
If you’re concerned about your liver or metabolic health, here are some steps you can take:
- Measure your waist: For many adults, a waist size above 90 cm (men) or 80 cm (women) is a red flag.
- Stay active: Regular movement, even walking or light cardio, helps reduce visceral fat.
- Eat a balanced diet: Focus on fiber-rich foods, cut back on sugar and refined carbs, and limit alcohol.
- Get regular checkups: Liver enzymes and ultrasound scans can reveal early signs of MASLD.
- Ask your doctor about BRI: While not standard yet, it may offer useful insight—especially if you’re lean but have a large waist.
Conclusion: A New Tool in the Fight Against Liver Disease
The body roundness index is emerging as a valuable tool in identifying people at risk for MASLD—especially those who wouldn’t be flagged by BMI alone. As liver disease continues to rise globally, tools like BRI could help catch problems earlier and support better health outcomes for people of all sizes.