In industrialized nations, our sedentary lifestyles have led to skyrocketing rates of obesity and diseases like diabetes. The answer, we are told, is exercise – voluntary physical activity for the sake of health. However, most of us struggle to stay fit, and our attitudes to exercise are plagued by misconceptions, finger-pointing, and anxiety. Drawing on over a decade of high-level research, Lieberman shows that, in fact, we never evolved to exercise. We are hardwired for moderate physical exertion throughout each day. Offering fascinating and illuminating insights from evolutionary biology and anthropology, he explains why and how exercise can promote health, debunks persistent myths about sitting, speed, strength, and endurance, and points the way towards how we can be more physically active in the modern world.