"Diet-related chronic diseases are a major public health concern in most developed countries. Numerous policies aimed at stemming the rise in obesity, ranging from informational campaigns on diet and nutrition, to policies that aim to change the relative prices of certain foods using the tax system, as well as regulation on how food is produced, packaged and retailed. We aim at providing a deeper understanding of the impact that different types of taxation policy interventions are likely to have on the diet-related outcomes. A first objective will be to carry out ex ante analyses of the impact of a range of tax policies, including different forms of taxes on saturated fat and sugar. A comparison of the impact of policy reform across two large countries within the European Union, France and the UK, will be implemented. If taxation is to be used as a policy tool at the EU level, it will be important to understand how and why the effects will differ across countries due to differences in consumer preferences and habits, retail market structure and regulatory environment. Both French and British micro panel data are used to implement empirical analysis of these kinds of cross-national policy interventions. A second objective will consist of estimating flexible and precise consumer substitution patterns to realistically represent food and drink consumption behaviour, both within and between food product groups, and over time. This objective deals with several key methodological issues, including how to take into account variation in preferences across households over thousands of differentiated products, and how to introduce health management issue into consumers’ demand. A final objective will focus on the relationship between obesity and the demographic characteristics and food purchasing behaviour of households, to understand what factors affect obesity status and what nutrients are responsible for weight gain."