Background paper for The State of Food Security and Nutrition in the World 2019 – The health and environmental consequences of our dietary choices impose costs on society that are currently not reflected in the price of those foods or diets that contribute to these detrimental impacts. This paper provides updated estimates of two major cost items: the healthcare-related costs associated with unhealthy diets, and the climate-change costs associated with the emissions attributable to diets and food production. Results suggest that the health and climate-change costs of current diets are substantial and projected to increase up to 1.3-1.7 trillion USD annually by 2030.