There's a fat that makes you thin, researchers say.
Brown fat, two new studies suggest, burn calories like a furnace. The research is raising hopes that it may someday be used to help people control their weight.
Until about three years ago, it was thought that only babies had brown fat because they don't shiver like adults, and use it to keep warm.
Then, scientists discovered that adults have it too, in small amounts in the upper back, on the side of the neck, in the dip between the collarbone and the shoulder, and along the spine.
Now, in one new study published in The Journal of Clinical Investigation, six men were cooled down for three hours, but not enough to make them shiver, and they burned an extra 250 calories.
Other data shows that when mice exercise, they release a hormone that turns white fat cells into fat-burning brown ones. And it may work the same way in humans. It may also explain why exercise burns more calories than you might expect.
It's too soon to recommend that you chill yourself to a slimmer waist, but does seem like brown fat is a fat we can learn to love.
To watch Dr. Holly Phillips' report on brown fat, click on the video in the player above.