Unhealthy diet is the leading risk factor for chronic disease worldwide, and in high-income countries leads to many poor health outcomes, including overweight and obesity, type 2 diabetes, cardiovascular disease, cancer, dental decay, and mental health problems. How is it possible that, despite global agreement on the now critical need to improve population diet, little progress has been made? At the core of the problem lies the fact that eating unhealthy food is now easier than eating healthily.