Extreme calorie restriction is not a practice that most people should try. Too many people are likely to simply yo-yo out of any initial weight loss. And pregnant women and children should never attempt it, lest they hinder development.
But Harvard's Sinclair is hoping to develop pills that will mimic the benefits of calorie restriction—without depriving us of chocolate or crumpling our sex drive. In 2006, he published a much-heralded study in Nature on a compound from red wine called resveratrol. Obese mice that received concentrated doses were just as healthy as skinny mice. They also lived longer and had superior endurance. "They were Lance Armstrong mice, except they were fat," he says. In a study this year, lean mice on resveratrol also had less heart disease, fewer cataracts, stronger bones and better motor function—though they did not live longer than normal. To the extent that resveratrol mimics calorie restriction and exercise, it may be because all three activate a protein called SIRT1, a member of the sirtuin family of enzymes. SIRT1 increases the formation of new mitochondria, the power plants of cells, and it revs up existing ones. Last month Sinclair published a study showing that SIRT1 also repairs chromosome breaks, helping to keep youthful genes switched on and aging genes turned off.
