Too much light slows brown fat, suggesting link with obesity

Making days longer with artificial light may slow brown fat's energy-burning abilities.

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Brown fat is supposed to be the friendly kind of fat. But making the days longer with artificial light may turn brown fat into an enemy in the battle against obesity, a mouse study suggests.

Compared with mice experiencing normal light cycles, mice exposed to longer periods of light gained fat — not because they were eating more or moving less, but because their brown fat wasn’t working efficiently. Brown fat in these mice converted fatty acids and glucose to heat more slowly than brown fat in mice experiencing normal days, researchers report May 11 in the Proceedings of the National Academy of Sciences. 

Finding a way to boost brown fat’s activity may combat the negative effects of extended time spent in artificial light, the scientists suggest.

photo of Ashley Yeager

Ashley Yeager is the associate news editor at Science News. She has worked at The Scientist, the Simons Foundation, Duke University and the W.M. Keck Observatory, and was the web producer for Science News from 2013 to 2015. She has a bachelor’s degree in journalism from the University of Tennessee, Knoxville, and a master’s degree in science writing from MIT.

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