How to shrink fat cells and exercise to make them healthier
Many of us may not be aware that body fat can be metabolically healthy – or vice versa – regardless of a person’s weight or shape.
“Healthy fat isn’t about the amount of fat,” says Jeffrey Horowitz, a University of Michigan professor of exercise and metabolism. It’s about how well the fat works, he said. “A person who has healthier fat is much better off than someone with the same body fat percentage whose fat is unhealthy.”
According to Horowitz, the fundamental difference between healthy and dysfunctional fat is the size of the fat cells. “The more small fat cells, the better,” he said.
Most importantly, you don’t have to lose weight or fat to make the body fat you already have more metabolically healthy.
Why Fat Cell Size Matters
Large fat cells, he said, are already filled with fat. They can’t store much more and tend to dump some of their overflowing contents into the bloodstream as fatty acids. From there, the fatty acids spill over to other organs such as the heart, muscles or liver and settle there. Fatty, well-marbled livers, muscles or hearts are undesirable (unless you are raising steers).
Small fat cells, on the other hand, can essentially expand Sipping fat from your blood. You want fat to stay in fat cells, Horowitz said.
Healthy fat cells also contain countless active mitochondria, the energy centers of every cell. Mitochondria convert oxygen and food into cellular energy. In general, the more mitochondria there are, the healthier and more resilient each cell is, including fat cells.
After all, healthy adipose tissue teems with blood vessels to carry oxygen and nutrients to fat cells, along with battalions of other cells most involved in immunity and helping fight inflammation. Without adequate blood flow and immune defense, the fatty tissue often becomes inflamed and scarred and releases substances into the bloodstream that trigger similar, unhealthy inflammation elsewhere in our body, even in people who are not overweight.
How exercise can remodel your fat cells
However, until recently, scientists weren’t sure if or how much our fat might change. That said, they knew that healthy adipose tissue can deteriorate and fill up with large, leaky cells, dysfunctional mitochondria, and inflammation.
However, whether this process could be reversed or slowed down remained unclear. Some studies in rodents in recent years have been encouraging, suggesting that physically active animals had metabolically healthier body fat percentages compared to sedentary rodents, even if they were all overweight by rodent standards.
But we’re not laboratory mice, and many questions remain about the malleability of our body fat.
However, a study published in June brought bright spots. In the study, researchers at the University of Copenhagen in Denmark biopsied abdominal fat from young sedentary men, older sedentary men and physically active older men, most of them long-time and frequent cyclists.
The fat cells of the older, sedentary men showed relatively poor mitochondrial health, with fewer mitochondria than in the young men’s fat and less energy produced by each mitochondrion. But the physically active men’s fat cells contained abundant mitochondria, even more than the young men’s adipose tissue, so their fat cells were better fueled overall. Their adipose tissue also showed fewer signs of incipient inflammation than the sedentary men’s fat, regardless of their age.
“Exercise training meant more mitochondria and better-functioning mitochondria,” and essentially healthier fat, said Anders Gudiksen, a professor of cell biology at the University of Copenhagen, who led the study.
But for anyone who might not have had the foresight of being a lifelong cyclist, another new study offers hope that starting exercise now, no matter how sedentary you might have been, could quickly improve your fat’s fitness.
For the new study, published in the Journal of Physiology and overseen by Horowitz, the researchers biopsied adipose tissue from 36 sedentary obese men and women and then asked them to exercise for 45 minutes or more vigorously for 20 minutes at a moderate pace drive -minute interval training four times a week for 12 weeks.
The volunteers’ diets were carefully monitored to ensure they did not lose weight. Otherwise, Horowitz says, changes in their adipose tissue could be due to weight loss and not exercise.
But without shedding pounds, the exercising volunteers still put their fat back on. They ended up with far more small fat cells and more capillaries to feed those cells. Their adipose tissue also contained fewer biochemical markers of inflammation and fewer symptoms of scarring and hardening around the fat cells.
These effects were observed regardless of whether the subjects drove moderately or hard. “Intensity didn’t matter,” Horowitz said, just that they were active.
In the short term, these changes should make adipose tissue better able to slurp up and store excess calories someone eats with large meals during the holidays, Horowitz said, a scenario that doesn’t necessarily mean weight gain. This fat is usually temporarily stored and soon converted into energy for other tissues such as muscle. But in the meantime, he said, it’s better to store such fat in fat cells, not in the liver or arteries.
The longer-term effects of exercise and fat revolve around inflammation, Horowitz said, and whether and how metabolically healthy fat contributes to a metabolically healthy body, even — and perhaps especially — when people are obese.
We need more research to fully understand what constitutes healthy fat, he said, and the types and amounts of exercise that are best to create or maintain it. But it already seems clear, he said, that exercise benefits both fat and the rest of your body, giving one more reason to ride, walk, jog, swim or whatever you choose today choose to be active.
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