“We’ve known for a long time that if you reduce the calorie intake of rats or mice, they live much longer,” says Mark Mattson, chief of the laboratory of neurosciences at the National Institute on Aging (NIA) in Baltimore.
What happens in species closer to humans is more complicated. Rhesus monkeys fed 30 percent fewer calories lived longer in a study at the University of Wisconsin, but not in a study at the NIA.
Why the different results? One possibility: The Wisconsin monkeys were fed fewer calories than monkeys fed as much high-sugar, high-fat food as they wanted. In contrast, the NIA monkeys were fed fewer calories than monkeys fed as much (low-sugar, low-fat) food as they needed to maintain their weight.