Long-Term Exercisers Have Healthier Belly Fat, Even If Obese, Study Finds

By Cara Michelle Miller

For people with obesity, the benefits of regular exercise extend far beyond weight loss. A recent study suggests that exercising regularly changes fat tissue in a way that allows any weight gained or regained to be stored more safely, compared to in those who do not exercise.

People who regularly exercise store excess fat under the skin rather than in or around vital organs, which reduces their risk of developing cardiovascular diseases, diabetes, and liver disease.

“We can have better metabolic health as a consequence of exercise by making our fat tissue healthier,” principal investigator Jeffrey Horowitz told The Epoch Times.

People get fat from weight gain, and weight gain commonly happens due to less physical activity, eating too much, and aging.

Horowitz said that it is important to reframe the way people think about fat: “Fat tissue isn’t the reason we gain weight; it’s just a place where we store that extra energy and weight,” he said.

“If you have a safe place to store fat, like under the skin in the abdomen or lower body, it’s better than storing it in an excessive amount in your liver or heart or pancreas or other tissues where it could cause a lot more health challenges,” added Horowitz, who is also a professor of movement science at the University of Michigan School of Kinesiology.

Regular Exercise Promotes Healthier Belly Fat

Exercise produced healthier fat that was less inflammatory and could be efficiently metabolized, the researchers found.

The study, published on Sept. 10 in Nature Metabolism, found that exercisers have fat tissue with distinct structural and biological features that help them store fat more effectively. 

Researchers compared two groups of adults with obesity: one group comprised 16 people who exercised at least four times a week for over two years while the other group had 16 people who did not exercise regularly. Participants were matched for body weight, fat levels, and sex. Fat tissue samples were collected from the belly area.

According to Horowitz, their fat tissue had:

• Increased Blood Flow

Exercisers had more blood vessels in their fat tissue, enhancing the delivery of oxygen and nutrients while aiding in the removal of waste products, which helps maintain metabolic function and reduces inflammation.

• Less Rigidity

People naturally gain and lose fat due to changing seasons and hormonal changes.

The fat tissue of regular exercisers was softer and more flexible compared to non-exercisers. Reduced rigidity helps fat cells expand more effectively. In regular exercisers, fat was more likely to be stored under the skin rather than around vital organs, where it can cause harm.

“When we experience periods of overeating and weight gain, it’s best to have fat tissue that can expand effectively and has good blood flow,” Horowitz said.

• Lower Inflammation

There were fewer inflammatory cells and markers in the fat tissue of those who exercised regularly. Inflammation in fat tissue has been linked to various chronic diseases such as diabetes, heart disease, and hypertension.

The researchers also grew fat tissue in the lab from cells collected from both exercisers and non-exercisers, and cells from the exercisers developed into a tissue that stored fat more effectively.

“Collectively, these factors suggest that fat tissue in exercisers may be metabolically healthier than in those who do not regularly exercise,” Cheehoon Ahn, the study’s first author who was a doctoral student at the University of Michigan and is now a postdoctoral research associate at Advent Health, told The Epoch Times in an email.

This study builds on earlier research conducted by Horowitz and Ahn, which demonstrated that while some improvements in fat tissue can be seen after a few weeks or months of exercise, significant and lasting benefits require consistent, long-term exercise.

Safer Weight Gain

The enhanced quality of fat tissue observed in regular exercisers suggests that even if people with obesity gain weight, their fat is more likely to be stored in healthier, subcutaneous areas—under the skin—rather than around crucial organs. This shift can reduce the risk of obesity-related complications.

One condition that is gaining increasing attention in the United States is nonalcoholic fatty liver disease, which primarily affects people who are overweight or obese. It involves unhealthy fat accumulation in the liver.

“The bottom line is that living a physically active lifestyle can improve health by making our fat tissue healthier,” Horowitz said.

Reasons of Benefit Unknown

“While our study highlights the benefits,” Ahn said, “we don’t exactly know how exercise induces these changes.” Hormonal shifts and molecular signaling between tissues likely play a key role in making fat tissue healthier, he noted.

Horowitz told The Epoch Times that the research team is currently studying whether adding exercise to a weight loss program leads to better health outcomes, particularly when some of the weight is regained. This next study will compare the effects of weight loss achieved through diet alone versus diet combined with exercise, as well as examine how the fat tissue of people who exercise differs from that of those who do not.

Further research will also aim to determine whether specific types or intensities of exercise yield more significant results. Understanding these nuances will provide deeper insights into how exercise influences overall health and fat metabolism, Horwitz added.