The growth in obesity and other diet related health problems in the UK over the past few decades is well documented. At this event we will present two pieces of research that help us better understand what is driving these changes. The first focuses on quantifying the importance of some of the main reasons why obesity levels have risen dramatically in the past 30 years, including changes in calorie intake and levels of physical activity. The second explores the impact that the recent ‘Great Recession’ has had on consumers’ food purchasing behaviour. The recession entailed shocks to consumers’ income and to food prices; how have these translated into changes in diets? Our research aims to shed light on these questions, and to help us better understand the broad factors which have driven changes in British diet quality.