The New York Times reports that calorie restriction, which extends the life spans of worms, flies, fish, and mice, may do the same for rhesus monkeys. In research at the Wisconsin National Primate Research Center, monkeys fed 30 percent fewer calories than a standard diet provides are healthier, and their mortality rate so far is lower. If the results are like those seen in mice, the lean and hungry monkeys could live as much as 40 percent longer.
Although "several thousand" Americans—including Mike Linksvayer, "a 36-year-old chief technology officer at a San Francisco nonprofit group" (right)—already have embarked on restricted-calorie diets, there is no human-specific experimental or epidemiological evidence that they will live longer as a result (it may just seem longer). In fact, the study on which the CDC relies for its current estimate of the death toll due to obesity found that thin people tend to die earlier than pudgy (but not obese) people, while the super-thin (such as Linksvayer, who is six feet tall and weighs 135 pounds) fare even worse. That finding is not definitive because it's hard to control for all the variables that might be associated with both thinness and higher mortality. Even tracking people like Linksvayer would not yield conclusive results, because they're a self-selected group who may be healthier (or less healthy) to begin with and probably have atypical lifestyles in other respects.
But let's assume, for the sake of argument, that what works in worms, flies, fish, mice, and (maybe) monkeys also works in people, and let's leave aside the possibility (discussed in the Times article) of a pill that can achieve the same results without all the hunger. In that case, minimizing morbidity and mortality would mean getting everyone to live like Mike Linksvayer, who subsists on a a diet of 2,000 or so calories a day that features delicacies such as fermented soybeans for breakfast, tofu and carrots for lunch, and vegan sausage, kale, and salad for dinner, supplemented by occasional weekend fasts. Linksvayer says he feels better than he did before he started this regimen six years ago, and if he happens to live longer too, that would just be icing on the cake (which I assume he does not otherwise get to enjoy). But under the expansive understanding of "public health" that is now almost universally accepted by academics and public officials, if the Linksvayer lifestyle really does postpone death, it's the government's duty to cajole, hector, tax, and regulate everyone into following it. Given how resistant Americans are to meeting the current weight recommendations, this is a project that should keep the government busy for a long time.