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Metabolism Roundup

February 29, 2008

Artificial sweeteners cause rats to slow down their metabolism and gain weight.

Transcript

BOB HIRSHON (host):
The benefits of heavy lifting. I’m Bob Hirshon and this is Science Update.

While jogging builds a kind of muscle fiber called Type 1, sprinting and weightlifting build Type II muscle fiber. Researchers at Boston University have found that at least in rats, Type II fibers do more than make you look muscular. Rats that had been genetically modified to have a lot of Type II muscle fiber stayed strong and fit, even when overfed, while normal rats got sick and obese. And while you can’t get genetically engineered like the rats, you can lift weights and build type II fiber the old fashioned way.

In related news, Purdue researchers found that rats fed foods with artificial sweeteners actually gained more weight than rats fed food sweetened with sugar. When the sensation of sweetness was followed by no calories, the rats slowed their metabolism and lost their ability to control how much they ate. I’m Bob Hirshon for AAAS, the Science Society.