Rapid urbanization and uneven development of the food retail environment

We investigate how the development of supermarkets and public markets in a large, rapidly urbanizing African city can shape the equitability of the food system. Using remotely sensed retailer location and population datasets, we analyze the spatial-temporal development of supermarkets and public markets in Lusaka, Zambia from 2004 to 2020. As Lusaka's population grew by 116%, we found that supermarkets increased from 9 to 54 (500%) while public markets increased from 52 to 65 (25%). Using SaTScan spatial-temporal analysis, we identified seven significant areas of high supermarket development (p < 0.05) clustered from 2013 to 2020 in lower density, higher income residential areas. During this period ten new community public markets were established, suggesting a lack of direct involvement by the government to establish public markets at a pace similar to population growth. Supermarket development without concomitant development of public markets can negatively impact food system equitability in two ways: 1) supermarket development is spatially uneven, favoring more food secure residential areas, thus limiting food access; 2) supermarket development is outpacing the establishment of public markets, which have more favorable food purchasing conditions for low-income households. Improving food security in rapidly growing Southern African cities will require policies that promote retailer diversity and aim to improve urban food system resilience and equitability.