Energy-dense food consumption declines after Mexico's tax

In January 2014, Mexico passed an 8% tax on nonessential foods with energy density 275 kcal/100 g, including salty snacks, chips, cakes, pastries, and frozen desserts. Using a dataset that follows household food purchases over time, Taillie and colleagues examined whether the volume of taxed foods showed greater declines in the post-tax period than would be expected based on purchasing trends prior to the tax (2012-2013). They found that the mean volume of purchases of taxed foods in 2014 declined by 25 g per capita per month (95% confidence interval = -46, -11), or a 5.1% change beyond what would have been expected based on pre-tax trends. This shift was not seen in the purchase of untaxed foods. Low SES households' purchases of taxed foods declined (relative to pre-tax trends) by 10.2% (-44 [-72, -16] g per capita per month) and medium SES households by 5.8% (-28 [-46, -11] g per capita per month), whereas high SES household purchases showed no post-tax shift. There was no corresponding increase in the purchase of untaxed foods.

Key study limitations include the use of self-reported household data, limitation to urban households (which comprise 75% of expenditures), and the lack of a true control group, as the tax was implemented nationally. However, Taillie and colleagues' study provides an early snapshot of overall shifts in food purchasing one year after implementation of the nonessential food tax. The authors state, "[the] results can orient Mexican policymakers, who every year decide on the continuation of the tax, as well as policymakers from others countries currently considering the implementation of taxes on unhealthy foods."