The pros:
[…]Seat belts, vaccines, clean tap water, and other modern miracles have dramatically boosted average life expectancies, to be sure—reducing annually the percentage of people who die before reaching the maximum life span—but CR alone demonstrably raises the maximum itself. In lab studies going back to the thirties, mice on severely limited diets have consistently lived as much as 50 percent longer than the oldest of their well-fed peers—the rodent equivalent of a human life stretched past the age of 160. And it isn’t just a mouse thing: Yeast cells, spiders, vinegar worms, rhesus monkeys—by now a veritable menagerie of species has been shown to benefit from CR’s life-extending effects. Despite the mounting evidence, however, the link between CR and longevity remained for many years a medical curiosity, its implications for human health intriguing, certainly, but unexplored.
[…] In 1991, however, the proposition was simplified somewhat when a team of eight bioscientists sealed themselves up for a two-year stint inside a giant, airtight terrarium in the Arizona desert—and promptly discovered that the hypothetically self-sustaining ecosystem they’d settled into could barely grow enough food to keep them alive. This revelation might have doomed the experiment (known as Biosphere 2) but for the fact that the team’s physician, UCLA pathologist Roy Walford, had been studying the Calorie Restriction phenomenon for decades and convinced his fellow econauts that—as long as they all ate carefully enough to get their daily share of essential nutrients—a year or two of near starvation wouldn’t hurt. When at last the Biosphere 2 crew emerged from their bubble, tests proved them healthier in nearly every nutritionally relevant respect than when they’d gone in, and the case for Calorie Restriction in humans was no longer purely circumstantial. [“The Fast Supper”, Julian Dibbell, New York Magazine]
For some more pros — and some of the cons — see the article at New York Magazine.