Marshaling data from fields as diverse as physical anthropology, primatology, genetics and medicine, he now proposes a controversial new hypothesis: that the trend toward slower aging and longer lives began much, much earlier, as our human ancestors evolved an increasingly powerful defense system to fight off the many ...

The idea that early humans lived "so long" is a common misunderstanding rooted in a statistical anomaly: while the average life expectancy for early humans (Upper Paleolithic) was only about 30 to 33 years, this was due to an incredibly high rate of infant and child mortality. Those who survived the dangerous early years actually had the potential to live quite long—into their 60s and 70s. They lived long primarily due to their extreme physical fitness and "ancestral" diet. They were foragers and hunters, meaning their cardiovascular health was elite, and they were free from "diseases of civilization" like obesity, Type 2 diabetes, and processed-sugar related ailments. Additionally, contrary to the "brutal" caveman stereotype, archaeological evidence shows that early human tribes were highly social and cared for their elderly and wounded, sharing food and providing protection, which allowed elders to survive long after they could no longer hunt or gather for themselves.