A young adult in the U.S. could add more than a decade to their life expectancy by changing their diet from a typical Western diet to an optimized diet that includes more legumes, whole grains and nuts, and less red and processed meat, according to a new study publishing February 8th in PLOS Medicine by Lars Fadnes of the University of Bergen, Norway, and colleagues. For older people, the anticipated gains to life expectancy from such dietary changes would be smaller but still substantial.