The way doctors treat illness today "is simple," wrote S. Jay Olshansky, a demographer at the University of Illinois. "As soon as a disease appears, … - David A. Sinclair

Hoelzel made it to 74, despite having subjected himself over the years to experiments that included swallowing gravel, glass beads, and ball bearings to study how long it would take for such objects to pass through his system. And people say I'm crazy.

Over fifty years, Goldman estimated, the potential economic benefits of delayed aging would add up to more than $7 trillion in the United States alone. And that's a conservative estimate, based on modest improvements in the percentages of older people living without a disease or disability. Whatever the dollar figure, though, the benefits "would accrue rapidly," Goldman's team wrote, "and would extend to all future generations,"

Trading reproduction for repair, the sirtuins order our bodies to "buckle down" in times of stress and protect us against the major diseases of aging: diabetes and heart disease, Alzheimer's disease and osteoporosis, even cancer. They mute the chronic, overactive inflammation that drives diseases such as atherosclerosis, metabolic disorders, ulcerative colitis, arthritis, and asthma. They prevent cell death and boost mitochondria, the power packs of the cell. They go to battle with muscle wasting, osteoporosis, and macular degeneration. In studies on mice, activating the sirtuins can improve DNA repair, boost memory, increase exercise endurance, and help the mice stay thin, regardless of what they eat. These are not wild guesses as to their power; scientists have established all of this in peer-reviewed studies published in journals such as Nature, Cell, and Science.