Poor diet, insufficient physical activity, and obesity are leading causes of premature mortality worldwide. Efforts to improve population diets, increase physical activity, and reduce obesity rates are hampered by: limitations in the measurement of dietary intake and physical activity levels; lack of quantification of the long-term impact of promising behaviour change interventions on population health; and lack of comparable estimates of cost-effectiveness for interventions. This multidisciplinary joint exchange programme will integrate research from well-established teams in the United Kingdom, Republic of Ireland, New Zealand and Australia, to consolidate complementary expertise, expand research boundaries, and develop joint capability. Our research exchange programme has three work packages, centred on the goal of improving knowledge about physical activity, diet and obesity and the impact of interventions aimed at improving population outcomes for these behaviours. Work Package 1 focuses on developing and validating new technologies to measure diet and physical activity behaviours. Work Package 2 focuses on modelling the impact of fiscal interventions on diet and nutrition and subsequent health outcomes in European, Australian and New Zealand (ANZ) populations. Work Package 3 focuses on developing a method for producing comparable estimates of the cost-effectiveness of policy and practice-relevant obesity interventions, including both individual treatment options and environmental change interventions. Above all, the programme will strengthen research links between European and ANZ partners to grow expertise and capacity in this important area.