Food environments are defined as the collective physical, economic, policy and socio-cultural surroundings, opportunities and conditions that influence people’s food and beverage choices and nutritional status (1-3). The effect of unhealthy food environments on children's nutrition is particularly worthy of investigation given the formation of food habits and preferences in childhood. Unhealthy food environments, characterised by a concentration of food outlets often selling energy dense, nutrient poor foods and ubiquitous fast-food marketing, have been shown to lead to unhealthy diets and excess energy intake which have life-long consequences with respect to morbidity and mortality (4). However, the evidence is US centric, inconsistent in effect and often cross-sectional (5).

Neighbourhood-level deprivation has been shown to be the stronger predictor of poor dietary behaviours and increased body mass during childhood, rather than neighbourhood food environments (6,7). High rates of housing mobility may result in differing 'exposure' to unhealthy food environments across childhood. In New Zealand, households in which young children live are mobile, with residential addresses changes occurring frequently during early childhood (8). Alongside this mobility, household vulnerability to factors that have an adverse effect on child health also varies during early childhood (9,10).

By using Growing Up in New Zealand data, this project has the potential to disentangle the contributions of household poverty, housing mobility and the food environment to childhood diet and obesity. Using data linked from three studies, this research aims to investigate the longitudinal relationship between exposure to unhealthy neighbourhood food environments (characterised by different outlets and advertising), household mobility, household deprivation, dietary behaviours (intake of takeaways and fizzy drinks) and excess body size for children aged 4 to 8 years.