Even if you aren't seeing results on your bathroom scale, exercise is making a difference in your health by turning "bad" fat into "good" fat, according to new research.
Studies presented at the annual meeting of the American Diabetes Association showed that both mice and men have beneficial "browning" of fat that comes from sedentary behavior if they exercise. For the mice, this came after 11 days of running on an exercise wheel; for the men, this came after 12 weeks of consistent exercise bike training.
Plus, when researchers tried transplanting the mouse's brown fat into other sedentary mice that had lots of fat, they found that the mice that received the fat transplant had improved insulin sensitivity and glucose tolerance. However, it remains to be seen if this benefit holds true for humans, too, since researchers are not yet able to transplant fat from one human to another in this way.
"Our results showed that exercise doesn't just have beneficial effects on muscle, it also affects fat," one of the researchers, Kristin Stanford, Ph.D., who is a postdoctoral fellow at Joslin Diabetes Center, said in a statement. "It's clear that when fat gets trained, it becomes browner and more metabolically active. We think there are factors being released into the bloodstream from the healthier fat that are working on other tissues."
Because both these studies have yet to be published in a peer-reviewed journal, they should be considered preliminary. But still, the Mayo Clinic points out that brown fat -- which is "turned on" when a person gets cold -- has gained the attention of researchers recently because it seems to burn calories.
In fact, a study published last year in the Journal of Clinical Investigation showed that cold temperatures seem to spur adult men's brown fat to burn calories; however, this calorie-burning effect didn't occur when the men were in warm temperatures.