As we age, it becomes easier to gain weight and harder to maintain muscle. Thus, our waistlines tend to fatten, our muscles weaken, and the physical tasks that once seemed trivial now seem tiring. The deterioration of mitochondria, the microscopic power plants within every cell responsible for converting food into biochemical fuel, has been implicated as a major cause of these changes. The loss of mitochondrial efficiency and number over time deprives us of living a longer, healthier life. It may come as no surprise to learn that mitochondrial biogenesis, the natural process in which your cells build new mitochondria, may hold the key to delaying the deterioration in your body's appearance, performance, and even aging. The Secret Life of Mitochondria seeks to explain the role of mitochondria as a major component of the beneficial health effects of exercise and to provide a simple, but scientifically sound, template for using nutrition to maximize the body's inherent ability to produce new mitochondria.