In this updated revision of his acclaimed book, Bursting with Energy, Dr. Frank Shallenberger makes a clear connection between the amount of energy you have and the amount of aging you do, pointing out that, in medical terms, aging refers to a loss of function, not chronology. A thirty-year old with no loss of function is identical to a twenty-year-old, he says. And the same is true for fully functional people in their sixties--they are the same as thirty-year-olds. According to Shallenberger, the loss of functions that result from aging are themselves the result of energy loss: more energy, less aging; less energy, more aging. When Dr. Shallenberger discusses anti-aging methods, he is actually talking about improving energy production. His work with patients over the years has proven that an energy deficit is the root cause of every disease and symptom, from cancer, to fatigue, to obesity.