So what needs to be done? By reviewing around 500 obesity-reduction research trials around the world, MGI has identified 74 interventions to address obesity in 18 areas. These include subsidised school meals for all, calorie and nutrition labelling, restrictions on advertising of high-calorie food and drinks, and public health campaigns. There were sufficient data on 44 of these to be able to measure potential impact if scaled up to a national level. The systemic nature of the obesity challenge and the highly variable quality of the data that are available mean that this analysis is directional rather than perfect. Indeed, we see our analysis as analogous to a 16th century map that has islands missing and misshapen continents, rather than a perfect 21st century map of the full range of solutions.