Changes in the healthfulness of food and beverage purchases from 2006 to 2020 in formal, mixed, and informal outlets in Mexico

Abstract Background: To better inform retail food environment policies in the global south, it is necessary to further understand the healthfulness of food and beverages purchased by type of food outlet over time. Methods: Using repeated cross-sectional data from the National Income and Expenditure Survey (ENIGH) in Mexico (2006 to 2020), we categorized food outlets as formal (supermarkets, chain convenience stores), informal (street markets, street vendors, acquaintances), fiscally mixed (public markets, small neighborhood stores, specialty stores), and others. We estimated the proportion of total purchases in each food outlet and the percentage of the types of foods purchased by outlet for the overall sample and stratified by education level and urbanicity. Results: In 2006, the food outlets with the largest proportions of ultra-processed foods purchases were chain convenience stores (49%), small neighborhood stores (37%) and supermarkets (35%). In contrast, the outlets with the highest proportions of minimally processed food purchases were street markets (83%), public markets (81%), and specialty stores (75%). Over time, households improved the proportion of expenditure in minimally processed foods in supermarkets and small neighborhood stores (49 to 56% and 46 to 48%, respectively). Conversely, the proportion of expenditures in minimally processed foods decreased from 70 to 63% in street vendors. Households without formal education and residing in rural localities increased their minimally processed food purchases in supermarkets and specialty stores, but decreased in street vendors, acquaintances and public markets. Households with higher education and residing in more urbanized areas increased their purchases of minimally processed foods in supermarkets and small neighborhood stores and decreased in street vendors. Households in metropolitan cities also decreased purchases of minimally processed foods in chain convenience stores and specialty stores. Conclusions: Over time, purchases from informal outlets were healthier compared to purchases from the formal and mixed sectors, but no outlet sold only healthy or unhealthy foods. To ensure access to healthy foods, food policies should consider where the largest proportion of food purchases is being made, where the healthiest purchases are, and why some purchases from certain food outlets are becoming healthier, while in others they are becoming less healthy.