It is undeniably the case that both diet and exercise influence the course of aging, though the size of the beneficial effect, even in the case of optimal lifestyle choices, is nowhere near as large as we’d all like it to be. Animal studies show calorie restriction extending maximum life span in mice by up to 40%, as well as lesser effects from various other forms of dietary strategy. Exercise meanwhile doesn’t extend life span in mice, but does postpone age-related dysfunction and disease. Unfortunately, the effects on life span due to any of the strategies that are based on the metabolic effects of exercise and reduced calorie intake scale down as species life span scales up. These lifestyle choices upregulate stress response mechanisms, such as the cellular housekeeping systems of autophagy, resulting in more functional, less damaged cells. Yet calorie restriction, while extending mouse life span significantly, adds no more than a few years at most to human life spans.
That said, the beneficial effects of a good diet and regular moderate exercise are highly reliable, and they cost nothing beyond the time and willpower needed to