Beyond Proximity: Food Vendor Landscapes, Everyday Food Sourcing, and Dietary Diversity in Three Nairobi Neighborhoods.

Urban food environments in rapidly growing sub-Saharan African cities are shaped by informality, density, and income inequality, yet few studies integrate spatial analysis with participatory methods to explain how residents navigate these environments and how this relates to dietary diversity. We conducted a cross-sectional, descriptive mixed-methods study (August 2023-January 2024) across three income-diverse Nairobi neighborhoods: Westlands (high-income), Kasarani (middle-income), and Viwandani (low-income). We mapped 3548 food vendors and conducted photo-elicited interviews with 22 participants. Vendor clustering was assessed using Ripley's K-function, and dietary diversity was measured using Minimum Dietary Diversity for Women (MDD-W) from a 3-day photo-assisted recall. Informal vendors dominated across neighborhoods, with a higher share of formal outlets in Westlands. Vendors were significantly clustered in all three neighborhoods, with the strongest clustering observed in Kasarani and clustering occurring at fine spatial scales. Food sourcing differed by neighborhood: Westlands participants most often described supermarket use alongside informal vendors; Kasarani showed mixed sourcing across formal and informal outlets; and Viwandani relied predominantly on informal vendors, i.e., retail shops/kiosks and cooked-food street vendors. Dietary diversity was highest in Westlands (mean MDD-W = 5.19, SD = 1.03), moderate in Viwandani (4.61, SD = 0.39), and lowest in Kasarani (4.48, SD = 1.02). Narratives highlighted recurring determinants, e.g., nutrition/health, affordability, convenience/time, food safety, cultural background, and vendor relationships, showing that proximity and clustering alone did not ensure higher dietary diversity. Integrating spatial and narrative evidence suggests neighborhood food environments function as both geographic and social systems, where vendor distribution interacts with constraints and norms to shape diets across income contexts.