Karen Lee is a force for good around the world, secretly helping people to improve their diets, get in shape and live longer. In the vital but poorly understood world of public health, this Canadian woman is an international superstar. In the early 2000s, she went to the US to head a team of "health detectives" for the Centers for Disease Control and Prevention. By then, smoking was in decline thanks in part to the CDC's efforts and so its attention turned to the next biggest causes of premature death: over-eating and under-exercising. Her zeal in seeking out the root causes of the problem⁠—in schools, restaurants, in an environment that in general encouraged a sedentary, calorie-packed way of life⁠—was matched by her inspired approach to finding solutions. Going from strength to strength, she was next recruited by the City of New York⁠—where she helped introduce the calorie counts that are now on menus everywhere. In many other ways, her influence has since spread around the world. Karen has always known that health education and public service announcements are not enough. The world around us needs to change to encourage us to take the steps (literally and figuratively) to save our own lives. Working with civic leaders, city planners and architects, she has been a hugely influential pioneer in helping communities and organizations use our buildings, streets and neighbourhoods, and the amenities in them to address today's leading health problems, such as heart disease, stroke, cancers and diabetes. Fit Cities is a riveting memoir of that work⁠—the story of how Karen and her many teams of brilliant collaborators uncovered, and set about eradicating, the causes of a pandemic of unhealthy living. It is a story of hidden forces conspiring against our health, and of the battle against them. And every step of the way, it offers readers invaluable information and advice on how to live a healthier life.