Spatial Relationship Between Diet Diversity, the Food Environment and Transport: A Case Study in South Africa

Food and nutrition insecurity are prevalent issues in South Africa with health consequences. The country is seeing a paradox of diet quality resulting in the double-burden of malnutrition. While affordability and food preferences contribute to diet behaviour, the food environment influences diet patterns and food purchasing behaviour. This study examined the spatial relationship between nutrient security, purchasing behaviours and accessing the food environment. This study focused on Worcester, South Africa, a secondary city about 112 km from Cape Town. Through household surveys (n = 657), demographic, diet log within the last 24 h, food purchasing and transport behaviour data were collected. All surveys included GPS coordinates of the residence. Diet diversity score, measured by the diet log, was used as a proxy to measure nutrient security, with scores less than 4 indicating nutrition insecurity. In addition, all food retailers in the area were codified by type (supermarket, spaza, produce market, etc.) and geocoded. All minibus taxi ranks and routes were mapped. Regression and spatial analyses were performed using R Statistical Software and ArcGIS Pro. Diet Diversity scores averaged at 4 with little variation by income type. Results showed neighbourhood-level clustering of food and diet patterns with an overlapping density of spaza shops. Further, there was a spatial relationship of supermarket and spaza proximity whereas diet is more diverse near supermarkets while spazas provided a protection against food insecurity. While many residents walked to shops, taxi ranks were commonly used for larger purchases. Results from this study can inform local economic and planning officials on the relationship between the transport, food environment and nutrient security, thus providing evidence to support strategies aimed at improving healthy food availability in areas with higher rates of nutrient insecurity. These findings can help planners in prioritizing areas for healthy food accessibility.