The LEAP programme aims to understand the health, environment, social and economic effects of meat and dairy consumption to provide evidence and tools for decision makers to promote healthy and sustainable diets. The four year project (2017-2021) is a collaboration between the University of Oxford, the International Food Policy Research Institute (IFPRI), the supermarket group Sainsbury’s and The Nature Conservancy and is supported by the Wellcome Trust’s Our Planet Our Health Programme. The Challenge The global average consumption of meat and dairy are rising, driven by increasing incomes and population growth. The growing demand for meat matters as it’s consumption has significant effects on people’s health and livestock production can have major environmental impacts. Meat can be an important source of some nutrients, but there is also evidence that high meat consumption may increase the risk for some types of chronic disease. Livestock production is also a major source of greenhouse gases and other pollutants, increases water scarcity in some regions and can exacerbate soil erosion. However, livestock provides largescale employment and the trade in livestock and related food products is a core component of the economy of many countries. Policy makers are increasingly grappling with the economic, health and environmental consequences of rising meat consumption and these issues are particularly complex given the multiple narratives about eating meat and dairy that influence everyone’s behaviour.