New Heart Health Guidelines Focus on Belly Fat, Not Just Body Weight

 

When it comes to assessing your risk for heart disease, you need to think not only about how much you weigh, but where you carry any extra pounds. That’s because people who have what’s considered a healthy weight based on their body mass index (BMI) can still have an increased risk for heart disease if they have extra fat around their midsection, according to guidelines from the American Heart Association (AHA) published in April 2021 in Circulation.

This means that even if you’re not overweight, your next physical should involve a tape measure around your waist in addition to a check of your height and weight, according to the AHA. That’s because a growing body of evidence suggests that extra belly fat is a sign that you may have too much so-called visceral adipose tissue, a type of fat that wraps around abdominal organs and is a risk factor for cardiovascular disease. “Having more visceral adipose tissue is associated with greater risk of cardiovascular disease at all BMI levels,” says Marie-Pierre St-Onge, PhD, senior author of the AHA guidelines and an associate professor of nutritional medicine at Columbia University Irving Medical Center in New York City.

Why Visceral Fat Matters

The problem with visceral fat accumulation around internal organs like the liver and heart is that these fat stores can contribute to increased inflammation and higher blood lipid levels, says Laura den Hartigh, PhD, a research associate professor in the Diabetes Institute at the University of Washington School of Medicine in Seattle. Both inflammation and hyperlipidemia, or high lipid levels, can contribute to the development of atherosclerosis, the accumulation of plaque in artery walls that can obstruct blood flow and lead to cardiovascular events like heart attacks and strokes, Dr. den Hartigh says. Visceral fat carries this risk, but the subcutaneous layer of fat right under the skin does not. “Precisely where our fat is located dictates whether it puts us at increased risk for heart attacks and strokes,” den Hartigh says.

Differences in where people accumulate fat stores may also help explain why some people who have a healthy weight based on their BMI are still “metabolically unhealthy” with high blood lipid levels, inflammation, elevated blood pressure, and elevated blood sugar, den Hartigh adds. Visceral fat around the midsection in particular can lead people to be metabolically unhealthy even when their BMI suggests that they should be at low risk for cardiovascular disease. At the same time, people with obesity who don’t carry much fat around their midsection might actually be “metabolically healthy” without any other risk factors for cardiovascular disease beyond a high BMI, den Hartigh says. “The amount of belly fat we have surrounding our internal organs is correlated with our metabolic health, no matter how much total body fat we have,” den Hartigh says.

Previous Studies Show the Risks of Visceral Fat

Many previous studies, some dating back a decade or longer, have identified visceral fat as an independent risk factor for cardiovascular disease. One study, published in 2018 in the European Heart Journal, for example, followed more than 296,000 middle-aged women without heart disease for an average of five years to see how many of them developed cardiovascular disease or experienced events like a heart attack or stroke. Compared with people with a BMI of 22, within the healthy range, each 4.3-point increase in BMI for men and each 5.2-point increase in BMI for women was associated with a 13 percent higher risk of cardiovascular events.

In this study, researchers also looked at what happened when people with a healthy BMI of 22 carried extra fat around their midsection. At a BMI of 22, each 4.5-inch increase in waist circumference beyond about 33 inches for men and each 5-inch increase in waist circumference beyond about 29 inches for women was associated with a 10 percent higher risk of cardiovascular disease.

Another study, published in 2015 in the Annals of Internal Medicine, examined data collected over almost two decades on more than 15,000 adults to explore the connection between belly fat and mortality. Men with excess belly fat and a normal BMI were more than twice as likely to die during the study as men with obesity who didn’t have a high waist circumference, while women with a normal BMI and excess belly fat had a 32 percent higher mortality risk.

What to Do if You Have Excess Belly Fat

Unfortunately, there’s no quick fix diet or exercise plan that can target weight loss specifically for your midsection, Dr. St-Onge says. The good news, however, is that losing weight in general can lead to less fat all over your body as well as improvements in overall health, St. Onge adds. “As little as 5 percent weight loss can lead to improvements in health markers in those with overweight and obesity,” St-Onge says. “For those with a BMI in the normal range, but with a larger midsection, weight loss could also be helpful.”

And getting the minimum recommended amount of exercise for adults — 150 minutes a week of moderate-intensity physical activity — may be enough to see a meaningful reduction in belly fat, according to the AHA guidelines. Beyond just aiding weight loss, lifestyle changes like improving your eating and exercise habits can help improve metabolic risk factors for cardiovascular disease like blood sugar, blood pressure, and inflammation, the AHA guidelines also note.

While both cutting calories and getting more exercise can aid weight loss, stepping up your workouts may make a bigger difference in reducing visceral fat, says George Bray, MD, of the Pennington Biomedical Research Center at Louisiana State University in Baton Rouge, Louisiana.Lifestyle changes alone may not be enough to always reduce the risk of cardiovascular disease, particularly in people with severe obesity, according to the AHA guidelines. For these people, bariatric surgery produces more dramatic weight loss, bigger improvements in metabolic risk factors for cardiovascular disease, and a lower risk of mortality from cardiovascular causes, the AHA advises.

At the end of the day, the best approach for improved heart health is the one that helps you lose the most weight and keep it off over time, St-Onge says.“At equal amounts of weight loss, bariatric surgery and lifestyle modifications both lead to substantial reduction in risk,” St-Onge says.