Understanding the Role of Food Environments in Shaping Dietary Behaviour and Obesity Risk Among Urban Working Adults in Lagos State: An Ecological Study

The food environment, encompassing the physical, social, economic, and informational dimensions of food access and exposure, is increasingly theorised as a primary structural driver of dietary behaviour and obesity risk in urban settings. In Lagos State, where adult obesity prevalence has increased substantially over the past decade alongside rapid commercial food environment expansion, understanding these environmental determinants is critical for designing effective prevention policies. This thesis presents a comprehensive ecological study investigating the role of food environments in shaping dietary behaviour and obesity risk among urban working adults in Lagos State. The study employed a stratified spatial sampling design across fifteen local government areas stratified by socioeconomic level. A cohort of 980 working adults aged 25 to 55 years completed validated dietary diversity and ultra-processed food consumption questionnaires, provided anthropometric measurements, and underwent geographic positioning system activity tracking over fourteen days to map actual food environment exposure. Food environment audit data including outlet density, healthy food availability, pricing, and marketing exposure were collected at the neighbourhood level using standardised audit instruments. Multilevel regression models estimated associations between food environment characteristics, dietary outcomes, and body mass index. Results demonstrated significant neighbourhood-level variance in both ultra-processed food consumption (intraclass correlation: 0.18) and body mass index (intraclass correlation: 0.14). Fast food outlet density and proximity were independently associated with ultra-processed food consumption. Healthy food store density was protective against dietary diversity score below minimum adequacy. The study provides robust ecological evidence supporting food environment policy interventions in Lagos State. Keywords: food environment, dietary behaviour, obesity, urban adults, Lagos.