This Type of Fat Ages Your Heart the Most, Even at a “Healthy” Weight (How to Spot It Early)

In the United States, heart disease remains the leading cause of death, accounting for more than 915,973 deaths in 2023 alone, roughly one death every 34 seconds. Cardiovascular disease continues to claim more lives than cancer and accidents combined, and heart attacks and strokes together make up a significant proportion of those tolls.

Most people are familiar with common risk factors such as high blood pressure, smoking, high LDL (“bad”) cholesterol, and diabetes. But newer research is uncovering a stealthier contributor to cardiovascular aging that doesn’t always show up on a scale or in your BMI: hidden fat. Specifically, visceral fat, the fat stored deep around internal organs, appears to play a far more direct role in accelerating vascular aging and increasing the risk of heart disease than overall body weight does.

Subcutaneous vs. Visceral

When people talk about “body fat,” they’re often referring to subcutaneous fat, the layer you can pinch just under the skin. That kind of fat contributes to overall body shape and influences metabolic health to some extent, but it’s not nearly as metabolically active as the fat stored deep in the abdomen.

Visceral adipose tissue sits around internal organs such as the liver, pancreas, and intestines. This hidden fat doesn’t just add volume, it actively secretes hormones and inflammatory molecules that interact with metabolism and blood vessels in ways that promote cardiovascular disease. Recent studies emphasize that visceral fat increases atherosclerotic risk and contributes to stiffer blood vessels, factors that underlie heart attacks, strokes, and other serious outcomes.

Crucially, visceral fat may be present even in people who have a “normal” BMI. This means someone can appear lean yet still carry high cardiovascular risk due to fat distribution. Traditional metrics like BMI may miss a key piece of the risk puzzle.

How Visceral Fat Ages the Heart

Visceral fat is not inert. Biologically, this depot of fat releases pro-inflammatory cytokines and free fatty acids into the bloodstream. These substances contribute to a cascade of metabolic disruptions including insulin resistance, endothelial dysfunction (when the lining of blood vessels doesn’t work properly), and chronic low-grade inflammation — all of which accelerate cardiovascular aging.

One way researchers assess this effect is through measures of aortic distensibility and other markers of vascular health. A less distensible (stiffer) aorta means the heart must work harder to pump blood, a sign of accelerated cardiovascular aging and higher risk for heart attacks and strokes. Studies have found that higher levels of visceral fat correlate with reduced aortic distensibility, indicating stiffer vessels and higher risk of atherosclerotic disease, even in individuals with normal BMI. Visceral fat’s impact on heart health includes:

Increased inflammation: Visceral fat secretes inflammatory factors that damage blood vessels and promote plaque buildup.

Impaired insulin sensitivity: This fat type is more closely linked to insulin resistance, a precursor to type 2 diabetes and heart disease.

Elevated risk of atherosclerosis: Visceral fat correlates with thicker arterial walls and reduced elasticity, which are core components of cardiovascular aging.

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Together, these mechanisms help explain why individuals with similar weights and BMIs can have very different cardiovascular profiles.

Why BMI Isn’t Always a Reliable Indicator

Body Mass Index (BMI) has been widely used as a straightforward gauge of weight relative to height. But BMI doesn’t distinguish between muscle mass, subcutaneous fat, and visceral fat. A muscular individual may have a high BMI but low cardiovascular risk, while someone with normal BMI could carry high levels of visceral fat and be at elevated risk.

In fact, research has shown that visceral adiposity is a stronger predictor of atherosclerotic cardiovascular disease (ASCVD) than BMI alone, especially in people with normal or overweight BMI ranges. This challenges the idea that weight alone should guide cardiovascular risk assessment. Tools like waist circumference, waist-to-hip ratio, and imaging-based measures (CT or MRI) provide deeper insight into where fat is stored and how it may affect health.

In practice, this means that a slender appearance doesn’t guarantee heart health, what’s under the surface matters more.

Fat Distribution Shapes Heart Risk Differently

Patterns of fat distribution vary by sex and age. For example:

Men tend to store more visceral fat in the abdomen, which may partly explain why cardiovascular disease often develops earlier in men than in women.

Women, especially pre-menopausal women, are more likely to store fat in subcutaneous depots like hips and thighs, which may be less harmful metabolically.

After menopause, women often accrue more visceral fat, corresponding with rising cardiovascular risk.

These differences reflect hormonal influences on fat storage and metabolism, and they help explain why two people with similar BMIs can have different cardiovascular health trajectories.

Fat in the Liver and Other Hidden Depots Also Matter

It’s not just visceral fat around the organs that plays a role. Fat accumulation within the liver is a condition known as non-alcoholic fatty liver disease (NAFLD), which also contributes to cardiovascular risk. Elevated liver fat is associated with systemic inflammation, insulin resistance, and dyslipidemia, all of which increase the likelihood of heart disease.

Similarly, intermuscular fat (fat nestled between muscle fibers) has been linked with poorer metabolic outcomes and adverse cardiovascular risk profiles. These fat depots don’t cause changes in body shape that are visually apparent, but metabolically they contribute to the same harmful processes that visceral fat does.

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What This Means for Heart Health

Recognizing that hidden fat, not just visible weight, affects cardiovascular health shifts how we should think about prevention and risk:

Focus on Where Fat Is Stored

Assessments like waist circumference and waist-to-hip ratio offer clues about visceral fat and should be used alongside BMI in risk evaluation.

Target Visceral Fat With Lifestyle Changes

Lifestyle interventions can preferentially reduce harmful fat depots:

Regular physical activity, especially a mix of aerobic and resistance training, is effective for reducing visceral fat and improving metabolic markers.

Healthy eating patterns including plenty of vegetables, lean proteins, fiber, and unsaturated fats support fat loss and reduce inflammation.

Stress management and sleep optimization also influence fat distribution and metabolic balance.

Monitor Metabolic Health Markers

Tests like fasting insulin, glucose, triglycerides, and inflammatory markers can help clarify risk beyond weight measurements. When visceral fat is present, these biomarkers often shift in patterns that signal elevated cardiovascular risk.

The information on this website is meant to educate, not replace medical advice. Before you make any changes to your diet, lifestyle, or exercise routine based on what you read here, talk to a qualified healthcare professional who can evaluate your personal health and give you proper guidance.