Hidden fat inside the abdomen and liver linked to artery damage
A new study led by researchers at McMaster University reveals that hidden fat deep inside the abdomen and liver may quietly damage arteries, even in people who appear healthy. Published in Communications Medicine on October 17, 2025, the findings challenge the traditional reliance on body-mass index (BMI) as the primary measure of obesity and cardiovascular risk.
What types of fat matter—and why they’re risky
Researchers focused on visceral fat, the fat that surrounds internal organs in the abdomen, and hepatic fat, the fat stored in the liver. Both types are known to increase risks for Type 2 diabetes, high blood pressure, and heart disease, but their impact on artery health had been less clear. Using advanced MRI imaging and data from more than 33,000 adults across Canada and the United Kingdom, the team examined how these fat depots relate to the health of the carotid arteries—key vessels in the neck that supply blood to the brain.
Key findings: fat distribution, artery health, and risk markers
The study found strong links between visceral fat and the buildup of carotid plaque as well as thickening of the artery walls. Liver fat showed a weaker but still meaningful association with artery changes. Importantly, these associations persisted even after adjusting for traditional cardiovascular risk factors such as cholesterol and blood pressure, suggesting that hidden fat contributes to artery damage beyond what BMI or standard risk models capture.
“You can’t always tell by looking at someone whether they have visceral or liver fat,” said Dr. Sonia Anand, a vascular medicine specialist and the study’s corresponding author. “This fat is metabolically active and dangerous; it’s linked to inflammation and artery damage even in people who aren’t visibly overweight. That’s why it’s so important to rethink how we assess obesity and cardiovascular risk.”
Implications for clinicians and the public
The findings point to a need for imaging-based assessments of fat distribution in some patients, moving beyond BMI and waist measurements. By identifying individuals with hidden fat accumulation, clinicians may better predict who is at risk for carotid artery disease, stroke, and heart attack and tailor interventions accordingly. For middle-aged adults especially, the study underscores that hidden fat—not just outward weight—can quietly elevate cardiovascular risk.
What comes next in research and practice
Lead author Russell de Souza emphasizes that the research expands our understanding of obesity-related risk. “The wake-up call is for clinicians and the public alike to consider fat distribution as a meaningful health signal,” he noted. Ongoing work will explore how lifestyle changes and targeted therapies might reduce visceral and hepatic fat and, in turn, protect arterial health.
About the study and collaborators
Researchers analyzed data from two large cohorts—the Canadian Alliance for Healthy Hearts and Minds (CAHHM) and the UK Biobank—using MRI to measure fat distribution and artery health. The project drew support from the Canadian Partnership Against Cancer, Heart and Stroke Foundation of Canada, and the Canadian Institutes of Health Research, among others, with MRI reading costs provided in-kind by Sunnybrook Hospital and IV contrast supplied by Bayer AG. The study also used data from the Canadian Partnership for Tomorrow’s Health and the PURE Study.
