Objective: To identify factors associated with food purchasing decisions and expenditure of South African supermarket shoppers across income levels.
Design: Intercept surveys were conducted, grocery receipts collated and expenditure coded into categories, with each category calculated as percentage of the total expenditure. In-supermarket food quality audit and shelf space measurements of foods such as fruits and vegetables (F&V) (healthy foods), snacks and sugar-sweetened beverages (SSB) (unhealthy foods) were also assessed. Shoppers and supermarkets were classified by high-, middle- and low-income socio-economic areas (SEA) of residential area and location, respectively. Shoppers were also classified as "out-shoppers" (persons shopping outside their residential SEA) and "in-shoppers" (persons shopping in their residential SEA). Data were analysed using descriptive analysis and ANOVA.
Setting: Supermarkets located in different SEA in urban Cape Town.
Participants: Three hundred ninety-five shoppers from eleven purposively selected supermarkets.
Results: Shelf space ratio of total healthy foods v. unhealthy foods in all the supermarkets was low, with supermarkets located in high SEA having the lowest ratio but better quality of fresh F&V. The share expenditure on SSB and snacks was higher than F&V in all SEA. Food secure shoppers spent more on food, but food items purchased frequently did not differ from the food insecure shoppers. Socio-economic status and food security were associated with greater expenditure on food items in supermarkets but not with overall healthier food purchases.
Conclusion: Urban supermarket shoppers in South Africa spent substantially more on unhealthy food items, which were also allocated greater shelf space, compared with healthier foods.
Keywords: Food expenditure; Food security; Retail food environment; Shelf space allocation; Shopping behaviours.