You Don't Have to Be Obese for Belly Fat to Harm You, Heart Experts Warn
Extra padding around the belly can spell trouble for the heart, even if you're not technically overweight.
That's among the conclusions of a new scientific statement from the American Heart Association (AHA), where experts lay out the heart risks of being "apple-shaped."
It encourages doctors to dust off those old-fashioned tape measures and make waist circumference part of patients' health assessments.
While obesity can raise the odds of developing heart disease, not all body fat is the same, said Dr. Ruwanthi Titano, a cardiologist and assistant professor at Mount Sinai's Icahn School of Medicine in New York City.
"We used to think everything is about BMI," Titano said. "But BMI does not tell you where fat cells are in the body."
Titano, who was not involved in the AHA statement, was referring to body mass index, which is a measure of weight in relation to height. BMI is commonly used to put people into weight categories like "overweight" and "obese," but it is actually a crude gauge.
What matters more is body fat and where it's carried, Titano said.
Research has found that fat concentrated around the mid-section is particularly problematic. A larger waist size can signal more visceral fat -- deep fat that wraps around the internal organs. And that type of fat is far from "inert," Titano said.
Visceral fat, she explained, appears to be more "metabolically active" than fat that accumulates under the skin of the hips and thighs. It releases cytokines and other substances that promote inflammation and can inflict damage on the blood vessels and organs.
Visceral fat is also associated with insulin resistance, Titano said. That's a loss of sensitivity to the blood-sugar-regulating hormone insulin, which can lead to type 2 diabetes, a major risk factor for heart disease and stroke.
Wrapping a tape measure around the waist does not precisely gauge visceral fat. But there is a good correlation between waist size and that deeper fat, Titano said.
When does heart risk rise?
According to the U.S. National Heart, Lung, and Blood Institute, the risk of heart disease rises when waist size expands beyond 35 inches for women and 40 inches for men.
Dr. Tiffany Powell-Wiley, an investigator with the NHLBI, led the writing committee on the AHA statement.
When it comes to managing extra belly fat, there are no magic diets, she said.
Instead, it comes down to the familiar mantra of portion control, and opting for "whole" foods -- fruits, vegetables, fiber-rich whole grains, beans, fish and lean meat -- over processed and sugar-laden foods, Powell-Wiley said.
As for exercise, the good news is that grueling workouts are not necessary.
"It's aerobic exercise, the kind that gets your heart pumping, that's best for reducing abdominal fat," Powell-Wiley said.
Research suggests that moderate aerobic exercise, for 150 minutes a week, can do the job, Powell-Wiley said. And that includes activities like brisk walking.
Plus, she noted, exercise has many benefits beyond trimming waistlines. It improves cardiovascular fitness, which helps prevent heart disease, and makes daily tasks like stair-climbing easier. Exercise can also help people sleep more soundly, manage stress and just feel better, Powell-Wiley said.
"We're trying to move away from focusing on weight loss, and putting more attention on adopting a healthy lifestyle," she said.
One reason is because people can become discouraged if they don't see a big change on their bathroom scale.
But weight does not tell the whole story, Titano said. Body composition can change with exercise, meaning that fat around the middle may wither while muscle mass increases, she explained. That could show up as little change on the scale.
Again, Powell-Wiley said, that tape measure can come in handy if you want to track changes in your belly fat over time: Wrap it around your middle, just above the hip bones, and take the measurement after an exhalation.
Beyond that, Powell-Wiley said, you can take stock of how regular exercise and healthier eating make you feel -- whether you have more energy, less fatigue and greater capacity to manage those stairs.
She also stressed that no one is finger-wagging. Daily walks and diet changes are often talked about as "simple," but that may not be the case for people who lack time for exercise and money for healthy food, she noted.
The statement was published online April 22 in the AHA journal Circulation.
The U.S. National Heart, Lung, and Blood Institute has advice on maintaining a heart-healthy lifestyle.
SOURCES: Tiffany M. Powell-Wiley, MD, MPH, chief, Social Determinants of Obesity and Cardiovascular Risk Laboratory, U.S. National Heart, Lung, and Blood Institute, Bethesda, Md.; Ruwanthi Titano, MD, assistant professor, medicine/cardiology, Icahn School of Medicine at Mount Sinai, New York City; Circulation, April 22, 2021, online