Changes in Food at Home Purchases in Mexico Associated With the North American Free Trade Agreement: An Interrupted Time Series Analysis

ABSTRACT International trade affects food systems, modifying the availability and prices of foods. This study evaluates the association between the implementation of the North American Free Trade Agreement (NAFTA) with changes in the quantity of food and beverages purchased by Mexican households between 1984 and 2018. Two‐part models were used to adapt interrupted time series analysis, considering an inflection point in 1994 (when NAFTA came into force). We found that immediately after implementation of NAFTA there were reductions in purchases of milk (−11.4 ml/AE) and basic foods (−37.9 g/AE), together with increases in purchases of sugar‐sweetened beverages (+94 ml/AE) and nonessential energy‐dense foods (+7.3 g/AE). The post‐1994 trend shows positive average differences in purchases of cereals (+13.7 g/AE) and nonessential energy‐dense foods (+9.4 g/AE), together with a negative difference in tortillas (−10 g/AE) and plant‐based foods (−11.1 g/AE) compared to pre‐intervention trend. These findings suggest that NAFTA was associated with lower purchases of healthier food and beverages such as basic foods and milk, together with an increase in purchases of nonessential energy‐dense foods and sugar‐sweetened beverages.