A cautious popular science article on calorie restriction: "Caloric restriction as a research discipline has actually been around for ages. The first demonstration of extending lifespan and improving health in rats by cutting calories was back in 1934, and since then the finding has been repeated in numerous species up to and including non-human primates. Animals subjected to caloric restriction while maintaining adequate vitamin, mineral, and protein intakes not only live longer, healthier lives, they also maintain vitality to an older age and have fewer visible signs of aging - such as white fur - compared to better-fed siblings. It is worth noting that we are not just talking about shedding a few pounds here. Animal studies show that, almost up to the point of frank starvation, the more calorie restriction the better when it comes to extending lifespan and health. ... Virtually every animal study ever done on caloric restriction has shown benefits for health and longevity, and now we have emerging studies showing that even intermittent caloric restriction may be beneficial, so it would be almost surprising if humans turned out to be the only species to have a negative response. Unlike research animals, however, humans don't live alone in pre-paid houses with the right kind of food carefully provided by scientists, so if caloric restriction is to be a feasible strategy for maintaining health as we age it has to be feasible to implement - in other words, doable and practical in real lives in the real world." People who write about calorie restriction without having made a serious attempt at trying it invariably exaggerate the difficulty. Practicing calorie restriction is both "doable and practical," and requires no more investment of time and willpower than any modestly challenging hobby.

Link: http://www.thedailybeast.com/articles/2011/06/18/caloric-restriction-the-science-of-eating-less-and-living-longer.html