HOW DID MEXICO’S SUGARY DRINKS AND JUNK FOODS TAX CHANGE SHOPPING BEHAVIORS, OVERALL AND ACROSS STORE TYPES?

In Mexico, the obesity and diabetes epidemiological emergencies prompted the government to implement a tax on sugary drinks and non-essential high-calorie foods in 2014. While previous evidence showed that these taxes were linked to declines in purchases of taxed foods and beverages, little is understood about how the taxes relate to other types of food purchasing behavior, including shopping across different store types. Understanding store-type shopping patterns is important for informing point-of-purchase policies to improve the healthfulness of purchases in Mexico. In addition, previous tax evaluations have not examined whether the tax led to declines in actual calories and sugar purchased, critical steps on the path to obesity prevention. Using packaged food and beverage purchasing data from a panel of Mexican households in 2015, first we used k-cluster analyses to classify Mexican households into multiple store-type shopping patterns and used multinomial logistic regressions to examine the socio-demographic characteristics associated to each pattern. We found 4 distinct shopping patterns for beverages and 3 shopping patterns for foods, each driven by the store-type where most purchases were made. Low -SES households had the highest probability of clustering into shopping patterns in which most taxed and untaxed beverages and foods were purchased at traditional stores, whereas high-SES households had the highest probability of clustering in shopping patterns in which most purchases occurred at supermarkets. Second, using beverage purchasing information from two years before (2012-2013) and three years after (2014-2016) the tax implementation from the same panel of Mexican households, we used fixed effects and inverse probability weighting, to examined changes in volume, calories and total sugar of packaged beverages overall and across store-types. Overall, we observed a reduction of 108 ml (-37%), 18 Kcal (-21%) and 5g of sugar (-23%) from purchases of taxed beverages between 2012 and 2016. Our findings showed that significant reductions happened in the first two years after the tax (2014-2015), but that the trend plateaued 3 years after the tax. Across most store-types, a decreasing trend in volume, calories and sugar from taxed beverages was also observed. While traditional stores were the main source of taxed beverages, supermarkets showed the steepest relative and absolute decline in taxed beverage purchases in the first post-tax year (2014). This suggests the tax effect was less pronounced at traditional stores, which contributed the most to taxed beverages, than it was at other store-types. Changes in calories and sugars across other store-types were minimal. In conclusion, there is variation in the combination of store-types where Mexican households purchase packaged foods and beverages, which is highly influenced by the households’ socioeconomic characteristics. Nevertheless, taxed beverages are mainly purchased at traditional stores regardless of store-type shopping patterns and SES status. Our results show that the Mexican tax on SSBs achieved its intended goal of lowering the purchases, calories and sugar of sugary beverages overall and across store-types even 3 years after the tax implementation. However, these trends plateaued by 2016 and overall reductions in calories and sugar from taxed beverages were small. In addition, mild changes were seen at traditional store types, where the most taxed beverages are purchased. These results suggest that policymakers should strengthen the SSB tax and consider implementing store-specific interventions to further reduce SSBs purchases in order to achieve the caloric and sugar reductions required to drive changes in the obesity epidemic.Doctor of Philosoph