Belly fat stiffens the heart, more in men, says study:  Why waist size, not weight, matters

Excess abdominal fat, often referred to as a “beer belly or belly fat”, may be changing the structure of the human heart, especially in men, raising the risk of heart disease. This fat pushes the contours of the heart even when the person’s overall weight may seem normal. Using advanced cardiac MRI technology, researchers at the University Medical Center Hamburg-Eppendorf, Germany, detected subtle alterations in heart tissue that standard imaging methods might miss.

The findings were presented at the annual meeting of the Radiological Society of North America. Researchers found that abdominal obesity, indicated by a high waist-to-hip ratio, was associated with “more concerning cardiac remodelling patterns than high body mass index (BMI) alone.” The study showed that the heart muscle thickens with belly fat although its overall size doesn’t increase. So, its inner chambers become smaller, which means the heart holds and pumps less blood, even affecting breathing. “This impairs the heart’s ability to relax properly, which eventually can lead to heart failure,” say researchers, who studied cardiovascular MRI images of 2,244 adults aged 46 to 78 (43% female) without known cardiovascular disease. According to BMI, 69% of males and 56% of females in the study were overweight or obese. Using waist-to-hip ratio, 91% of the males and 64% of females met the World Health Organization (WHO) criteria for obesity.

Dr Mukesh Goel, senior consultant, cardiothoracic and cardiovascular surgery, heart and lung transplant surgery, Indraprastha Apollo Hospitals, says almost all his patients with heart muscle weakness have a large waist size. “In several cases, their body mass index is not very high, but their waist size clearly shows abdominal obesity. This pattern is especially common in middle-aged men with sedentary lifestyles and regular alcohol consumption,” he says.

How can a beer belly impact the heart?

A beer belly usually means excess fat around the abdomen, called visceral fat. This is active tissue and releases harmful chemicals that increase inflammation, raise blood pressure, worsen cholesterol levels and reduce the body’s response to insulin. Over time, these changes force the heart to work harder. This can lead to thickening of heart muscles, stiffness of heart chambers and poor relaxation of the heart. These structural changes increase the risk of heart attacks, heart failure and rhythm problems. This is why abdominal fat is considered more harmful than fat stored in other parts of the body.

What is the ideal waist-to-hip ratio for good heart health?

Waist-to-hip ratio is a simple and useful measure of heart risk. For men, a healthy ratio is below 0.90. For women, it should be below 0.85. A higher ratio means more fat around the waist compared to the hips, which increases heart disease risk. Waist size alone is also important. Ideally, men should have a waist size below 90 cm and women below 80 cm. These numbers are especially relevant for Indians, who develop heart disease at lower waist sizes. Keeping waist measurements within these limits helps protect the heart over the long term.