Exercise Changes the Way Our Bodies Handle Saturated Fat, Study Finds

Scientists in the U.K. seem to have unearthed yet another benefit of exercise: It could make our bodies better at using up certain kinds of fat. In a new study out this week, researchers found that endurance athletes were much better at burning off saturated fat compared to sedentary people with type 2 diabetes—a distinction that emerged in the diabetic group once they began to exercise as well.

The research was led by scientists from the University of Aberdeen. They were interested in unraveling a particular biological mystery, known as the athlete’s paradox. Studies have found that endurance athletes and type 2 diabetics both tend to store higher amounts of fat inside their muscle fiber cells compared to others, despite being very different otherwise. Athletes are typically at much lower risk of cardiovascular disease than diabetics, for instance, and usually have high insulin sensitivity (by definition, those with type 2 cannot respond to or produce insulin effectively).

To get a better grasp on how this phenomenon happens, the researchers recruited 29 male endurance athletes and 30 patients with diabetes for an experiment.

First, the volunteers were injected with small amounts of different fats intravenously and had their thighs scanned via MRI to see how these fats were used by muscle cells. They also had their thigh muscle cells biopsied and had basic measurements of their metabolism taken. Then the volunteers basically swapped lives for the next eight weeks, with the exercisers avoiding their usual physical activity routine and the type 2 diabetics undergoing endurance training, to the point of exercising five hours a week. Following the eight weeks, the same tests were given once again.

The researchers found that the athletes’ bodies stored higher levels of saturated fat inside their muscle cells than those with diabetes, but were also very efficient at burning it off. Conversely, the bodies of the diabetics stored more unsaturated fat inside their muscles, but were worse at burning off either kind of fat. After the swap, however, the two groups began to mirror one another, with the exercising diabetics now storing and burning off saturated fat about as well as the deconditioned athletes.

The team’s findings, published Wednesday in Nature Communications, are based on a relatively small sample size. So more studies will be needed to confirm what the team has found here. But plenty of research has shown the many ways that exercise can improve our health for the better, so it’s certainly possible that this just might be another one of them.

“These results are completely novel and highlight how keeping fit and active improves metabolism of saturated fat as a direct benefit of exercise,” said senior study author Dana Dawson, chair of cardiovascular medicine at Aberdeen, in a statement from the university.

Better fat burning aside, the researchers also found that the people with diabetes lost weight, increased their insulin sensitivity, and lowered their levels of cholesterol, triglycerides and fasting glucose once they began exercising—all good enough reasons for anyone not exercising to start.

“When it comes to being active, it’s important to get into a routine that you enjoy and that you can stick to,” said Bryan Williams, chief scientific and medical officer at the British Heart Foundation, in a statement from the university. “Try to build up to 150 minutes of moderate intensity activity a week, such as a brisk walk, swimming or cycling.”