TUESDAY, Oct. 21, 2025 (HealthDay News) — Hidden deposits of fat deep inside the abdomen and liver can quietly increase your risk of stroke and heart attack, even if you appear to have a healthy weight.

Results from a new study showed that both liver fat and the visceral fat packed around internal organs increase risk for hardened and clogged arteries in the neck, researchers reported Oct. 17 in Communications Medicine.

People can have this sort of “skinny fat” even if their body mass index (BMI) is in the healthy range, researchers said. BMI is an estimate of body fat based on height and weight.

“You can’t always tell by looking at someone whether they have visceral or liver fat,” senior researcher Dr. Sonia Anand, a vascular medicine specialist with Hamilton Health Sciences in Ontario, Canada, said in a news release.

“This kind of fat is metabolically active and dangerous. It’s linked to inflammation and artery damage even in people who aren’t visibly overweight,” Anand said. “That’s why it’s so important to rethink how we assess obesity and cardiovascular risk.” 

For the new study, researchers analyzed MRI data from more than 33,000 adults in Canada and the U.K., looking at both their fat deposits and the health of their neck arteries.

Arteries in the neck feed blood to the brain, and their narrowing is a key predictor of stroke and heart attack, researchers said.

Increases in both visceral and liver fat were linked to a thickening of artery walls and a buildup of artery-clogging plaques.

“This study shows that even after accounting for traditional cardiovascular risk factors like cholesterol and blood pressure, visceral and liver fat still contribute to artery damage,” co-lead researcher Russell de Souza, an associate professor of health research methods, evidence and impact at McMaster University, said in a news release.

The results indicate that doctors need to consider using imaging-based assessments of fat distribution for patients, rather than relying on BMI, researchers said.

Middle-aged adults also should consider that hidden fat might be damaging their health, even if they don’t appear overly pudgy.

“The findings are a wake-up call for clinicians and the public alike,” de Souza said.

People can rid themselves of visceral fat by staying active, eating healthy, getting good sleep, reducing stress and limiting alcohol, according to the Cleveland Clinic.

More information

The Cleveland Clinic has more on visceral fat.

SOURCE: McMaster University, news release, Oct. 16, 2025