Several proteins are now known to influence longevity, energy use and the response to caloric restriction, including sirtuins (thought to help the body ride out famines), receptors for insulin, IGF-1, and TOR (“target of rapamycin”) — an antimicrobial that was recently found to extend lifespan significantly, even when given to mice at an advanced age).

Four active clinical trials of sirtuin activators (drugs that mimic resveratrol) are under way by Sirtris Pharmaceuticals.