CNN discusses calorie restriction in an introductory fashion - it's a good article to give to your friends as general health advice. Calorie restriction has been proven to extend healthy lifespan in mammals, and there is strong evidence that does the same in humans. (It is surmised, for example that Okinawans have a form of mild calorie restriction to thank for their famed longevity). The article also mentions the large national CALERIE study, funded by the NIA - this study should soon be turning out more data in support of calorie restriction as the smart choice for living healthily for longer. Less calories, more life!