Posted on: Saturday, June 5, 2004

Mammalian protein could 'fool' body into losing fat

By Elizabeth Weise
USA Today

Researchers at the Massachusetts Institute of Technology say they have discovered a protein that controls whether mammals store fat or shed it.

Biology professor Leonard Guarente found that when the protein — called Sirt1 — senses short-term famine, it turns off the receptors that keep fat stored in fat cells. When the protein turns those genes off, the body is prevented from storing fat, at least in the mice that were studied. The research by Guarente's team, paid for by the National Institutes of Health, is published in Wednesday's online edition of the journal Nature.

Near-starvation diets have been shown to extend life and prevent disease in many mammals. Whether it works in people is unclear, but lab findings on calorie restriction are fueling many studies of human longevity.

Researchers worldwide are looking for ways to chemically mimic starving without the inconvenience of actually missing meals. "It's easy to put rodents on a spartan diet. With people it's not so easy," Guarente says. "If we could make a drug that would bind to Sirt1 and fool the body into thinking that it needed to release that fat, then maybe people could get the benefits of calorie restriction without the side effects."

But even if such a drug were discovered, it turns out there's no such thing as a calorie-free lunch. Guarente suspects that to get the full benefits, vigorous exercise also would be required.