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| You can increase the amount of brown fat you have by sleeping in a cool room. |
Most people assume that all body fat
is made the same. We should have some of it, but not too much, and, as
we enter adulthood, it basically just sits there storing energy (and
building up in areas that we don’t want it to).
But that’s only part of fat’s story. We actually have two completely
different types of fat cells: Brown fat and white fat. And brown fat, as
it turns out, has one incredibly cool—and useful—function. It can burn
calories for you.
Scientists have known about these fat varieties for quite some time,
but a discovery in 2009 changed our view of their function. Brown fat
cells, unlike white, generate heat to keep us warm. That’s particularly
useful if you are a baby and you can’t shiver to keep yourself from
getting too cold. For that reason, scientists long assumed that only
babies possessed those cells. But a series of 2009 studies published at the same time in the New England Journal of Medicine showed that adults have some as well.
This discovery sparked more research, which is currently ongoing, on
how much of an effect these brown fat cells have. And, perhaps more
importantly, whether one can increase their quantity of brown fat cells
in order to lose weight.
What is brown fat? And what makes it different from other fat?
The main difference between white and brown fat lies in their color and namesake. Inside a white fat cell sits a single large lipid (fat) droplet and not much else. That fatty deposit gives the cell its color and claim to fame, storing energy and providing a nice cushion for our internal organs. It also produces a whole bunch of hormones, like estrogen and leptin (which regulates hunger), and contain receptors for others like insulin.But the composition of a brown fat cell is completely different. Instead of one huge fat chunk, it contains a handful of tiny fat droplets and a huge number of mitochondria. Those cellular powerhouses contain iron—giving them a brownish color, hence the name—which fuels them to burn away the tiny fat droplets. Yes, you have fat cells that burn the fat you eat. Ain't that nifty?
Should I have more brown fat cells than white ones?
It’s important to remember that white fat cells, while perhaps less glamorous than the fat-burning variety, are quite important. If we didn’t have any white fat, our internal organs would be constantly exposed and at-risk. We'd also be unable to regulate many of our hormones, and consequently, bodily functions.But it’s also true that white fat cells can accumulate to excess. This often happens when we consume more calories than we burn off. Too much white fat can lead to diseases like diabetes and obesity. Brown fat cells, on the other hand, are able to burn the fat inside of them, such that they help prevent extra fat from accumulating.
For the past several years, researchers have tried to figure out if adding more brown fat cells—or revving them up—could treat or prevent obesity. And if so, how much more brown fat do we need?
How can I get more of it?
Scientists haven’t quite uncovered all of brown fat's mysteries, but
it seems clear that increasing its activity in the body can be quite
beneficial. And there are a couple ways to boost your stores of the
stuff.
Brown fat becomes more active at lower temperatures. One of the 2009 New England Journal of Medicine
studies found that more brown fat becomes active when one sits in a
chilly room of 61 to 66 degrees Fahrenheit. Building on that research, a
2014 paper
had adult men sleep in a temperature-controlled room that the
researchers changed throughout the study. They found that sleeping at a
temperature of 66 degrees for a month, as opposed to the previous 75
degrees for four weeks, nearly doubled the volume of brown fat in
subjects' bodies. The participants also saw improvements in their
insulin sensitivity. The researchers concluded that the simple act of
turning down the thermostat at night, or at the office where you work,
could be good for your health.
Many recent studies have also found that exercise can also affect our
brown fat, by generating it or triggering existing cells to burn more
fat. Physical activity might even turn some white fat cells into brown.
Regular, moderate exercise is a sure-fire way to keep your fat cells
working in your favor.
Scientists are working hard to figure out what else brown fat does
for us and how else we can increase it. This month, researchers
reporting in the journal Small Methods described a patch designed to deliver drugs thought to increase brown fat production.
While we wait for scientists to figure out how to turn us into lean,
mean brown fat machines, it's important that we remember to maintain
healthy levels of white fat, too. The key is to exercise regularly,
reduce stress, and eat a balanced diet that—as always—includes a tremendous amount of fiber. Sleeping with the window cracked this winter might give you a tiny fat-burning boost, but getting to the gym every morning will do you a lot more good.