Can modern food retailers improve diets and nutrition in urban Africa? Empirical evidence from Zambia

In many developing countries, food environments are changing rapidly, with modern food retailers – such as supermarkets and convenience stores – increasingly replacing or complementing traditional food retailers. In comparison to traditional food markets and shops, modern retailers often sell a different range of products, at different prices and packaging sizes, and in different shopping atmospheres, thus affecting people’s food environments and potentially also their food choices, diets, and nutrition. Understanding the dietary and nutrition effects of a modernizing retail sector is important, as many countries in Africa suffer from a double or even a triple burden of malnutrition – i.e., the coexistence of undernutrition, micronutrient deficiencies, and overweight or obesity within the same communities, households, and even individuals – with serious negative health consequences. Recent research suggests that access to and affordability of healthy diets remain formidable challenges in many developing countries. However, empirical studies analyzing the effects of modern retailers on consumer diets, dietary costs, and nutrition remain scant. A few recent studies showed that the growth of modern retailers, especially supermarkets, in developing countries contributes to higher consumption of ultra-processed foods and rising rates of overweight and obesity among adults. For children, research on the links between modern retailers and child nutrition is still limited; the few existing studies found mixed results. In any case, the available evidence suggests that modern retailers may have different effects on dietary quality and nutrition among adults and children. One major drawback of existing studies is that they analyzed individual-level anthropometric data, yet without having individual-level dietary data to explain some of the underlying mechanisms. Therefore, none of the previous studies analyzed the effects of modern retailers – such as supermarkets – on dietary quality (i.e., nutrient intake) with individual-level dietary data to account for intra-household food distribution. Another drawback is that previous studies mostly focused on supermarkets, without accounting for the fact that other types of modern retailers – such as convenience stores and fast-food restaurants – are also gaining in importance as sources of food in urban Africa. Finally, the role of supermarkets and other modern retailers on the affordability of nutritious diets was not analyzed in any of the existing studies. We make several contributions to the existing literature by addressing the highlighted research gaps in the three papers of this dissertation. In the first paper, we examine the relationships between consumers’ socioeconomic status, use of different modern and traditional retailers, and dietary patterns. The analysis uses household survey data from urban Zambia. We surveyed a total of 475 urban households in 2018. Results show that two-thirds of the households use modern and traditional retailers simultaneously, but that richer households are more likely than poorer ones to use supermarkets and hypermarkets. Use of modern retailers is positively associated with higher consumption of ultra-processed foods, after also controlling for income and other socioeconomic factors. However, the use of traditional stores and kiosks is also positively associated with the consumption of ultra-processed foods, suggesting that modern retailers are not the only drivers of dietary transitions. In the second paper, we provide the first empirical study that analyzes effects of modern retailers on dietary quality and nutrition with individual-level food-intake/dietary and anthropometric data in a developing country. We collected data from 475 randomly selected households that use modern retailers at different intensities in Lusaka, Zambia. In these households, individual-level anthropometric and food-intake data were collected from 930 adults and 499 children. The data are analyzed with control function regression models to address potential endogeneity problems associated with food purchases made in modern retailers. We find that use of modern retailers is positively associated with overweight in adults, but not in children. For children, we find a positive effect on body height, also after controlling for income and other relevant factors. Use of modern retailers increases dietary diversity, calorie, protein, and micronutrient intakes among both adults and children. Effects on protein and micronutrient intakes are channeled primarily through higher consumption of meat and dairy products. In the third paper, we analyze effects of using supermarkets on the affordability of recommended nutritious diets and dietary quality. We use individual-level food-intake data and food price data from our household survey conducted in Lusaka, Zambia, and control function regression models to account for the likely endogeneity of supermarket food purchases. We find that the cost of a recommended nutritious diet is US$1.22 per day, of which the largest share is the cost of starchy staples (68%), followed by fruits (11%), and meat, eggs, and fish (9%). However, this diet is not affordable to 41% of low-income group. Meat, fish, and dairy products are more expensive in supermarkets than in traditional retailers. Nevertheless, buying food in supermarkets increases dietary diversity and intake of nutritious diets, with varying effect sizes among demographic cohorts: men, women, boys, and girls. The positive effects of supermarkets on dietary quality largely come from animal source foods. We draw several conclusions and policy implications from the three papers in this dissertation. The findings underline that the growth of modern food retailers in developing countries influences people’s diets and nutrition; the effects can be both positive and negative. The positive effects on child nutrition and dietary quality of both children and adults imply that further modernization of food environments should be promoted. However, due to higher quality food products and safety standards, modern retailers – such as supermarkets – offer higher prices for meat, fish, and dairy products than traditional retailers. Thus, the results suggest a need to shift food policy from focusing on energy-dense foods to affordable nutritious foods. Modern retailers could be one of the platforms to make nutritious foods – i.e., meat, fish, eggs, milk, and other dairy products – more affordable especially among poor households. Lower prices could come from improvements in local production, higher efficiency in procurements, marketing and trade, and infrastructure developments especially cooling facilities and warehouses. On the other hand, the increasing effect of modern retailers on the consumption of ultra-processed foods and adult overweight is undesirable and calls for certain policy regulations. Possible policy interventions include regulation of advertisement and promotional campaigns for unhealthy foods, regulation of health labels and portion/packaging sizes, taxes on ultra-processed foods and beverages with high contents of fats, added sugars and salts, among others. While the results cannot be generalized, effects may be similar also in other parts of Africa. Nevertheless, further research is needed to better understand the diet and nutrition effects of changing food environments in different geographical and socioeconomic contexts, and also focusing on long-run dynamics