Cutting calories to slow aging—without compromising health

Restricting calorie intake in species such as mice, rhesus monkeys, and fruit flies has been shown to extend their lifespans. In some cases, these animals not only live longer, but are also free of disease. But when pushed too far, calorie restriction can have negative impacts. Mice that undergo a 40% reduction in calorie intake, for example, are more susceptible to infections, less likely to reproduce, and experience stunted growth.