Food critic Giles Coren takes up three extreme regimens in an effort to push the limits of life expectancy and meets people from around the world whose pursuit of longevity is an obsession that dominates every aspect of their lives. He undertakes the calorie restriction diet, before going on one that consists only of foods hunted, fished or gathered by mankind's Paleolithic ancestors and ends with another made up almost entirely of fruit. Throughout the process, Giles's health is monitored by his doctor, who assesses the impact these dietary habits are having on his body.
