A recent study has found that hidden fat surrounding organs and stored in the liver can quietly damage arteries, even in people who appear lean.

Researchers at McMaster University in Canada analyzed MRI scans and health data from more than 33,000 adults in Canada and the United Kingdom. They discovered that visceral fat—the type that accumulates around internal organs—is strongly linked to thickening and blockage of the carotid arteries, which supply blood to the brain.

Published in Communications Medicine, the findings indicate that narrowing of these arteries is a major risk factor for stroke, and may also signal blockages in other vital vessels that feed the heart, increasing the likelihood of heart attacks.

Professor Russell de Souza, co-author of the study, stated:

“Even after accounting for traditional cardiovascular risk factors such as cholesterol and blood pressure, visceral and liver fat still play a major role in damaging arteries.”

Co-author Professor Marie Pigeyre added that the research highlights the need for more advanced ways to assess fat distribution, not just body weight:

“What truly matters is where fat is stored. Visceral fat is metabolically active and inflammatory, causing arterial damage even in people who aren’t visibly overweight.”

The study concludes that using advanced imaging techniques to detect hidden fat deposits could improve early prevention of heart disease and enable personalized treatment strategies based on internal fat composition rather than outward appearance.