Calorie-burning brown fat: How do we get more of it?
I'm a little obsessed lately with brown fat. As an avid exerciser, I read with great interest last week Gretchen Reynold's New York Times coverage of a new study published in the journal Nature, about a newly discovered hormone released in response to exercise (irisin), which turns white fat calls (essentially fat blobs) into brown fat (metabolically active stuff that actually burns calories).
And now there's more: Feeling chilled can "turn on" one form of brown fat, which then fuels itself partly by "sucking" fat out of the rest of body. When researchers put adult male subjects in a cold room, their metabolic rates jumped 80 percent. Once thought to be present only in mice and human infants (neither of which shiver as a defense against cold), brown fat helped defend the men who had more of it against feeling the chill longer. Almost everyone of normal weight or lower has brown fat, but the amount varies widely, say researchers; obese people almost never have it.
Possible practical applications of the new "brown fat" research are a long way off, researchers say—and they don't recommend making yourself cold in hopes of losing weight—but the potential seems fascinating to me. What do you think? I'd love to hear your comments.
For more actionable info on the exercise-metabolism link, read Delicious Living's "The Hormone Balance Plan." If your goal is to boost slowed metabolism, experts say, short bursts of intense exercise, including strength training, work better than long cardiovascular workouts, partly because they help balance metabolism-regulating hormones in the body.