Almost one in four people in OECD countries is currently obese. This epidemic has far-reaching consequences for individuals, society and the economy. Using microsimulation modelling, this book analyses the burden of obesity and overweight in 52 countries (including OECD, European Union and G20 countries), showing how overweight reduces life expectancy, increases healthcare costs, decreases workers' productivity and lowers GDP. The report makes the urgent economic case to scale up investments in policies to promote healthy lifestyles and tackle this growing global public health problem. The book evaluates a number of policies which could significantly improve health outcomes while being an excellent investment for countries.