To estimate changes in taxed and untaxed beverages by volume of beverage purchased after a sugar-sweetened beverage (SSB) tax was introduced in 2014 in Mexico.

We used household purchase data from January 2012 to December 2015. We first classified the sample into four groups based on pre-tax purchases of beverages: (i) higher purchases of taxed beverages and lower purchases of untaxed beverages (HTLU-unhealthier); (ii) higher purchases of both types of beverages (HTHU); (iii) lower purchases of taxed and untaxed beverages (LTLU); and (iv) lower purchases of taxed beverages and higher purchases of untaxed beverages (LTHU-healthier). Next, we estimated differences in purchases after the tax was implemented for each group compared with a counterfactual based on pre-tax trends using a fixed-effects model.

Areas with more than 50 000 residents in Mexico.

Households (n 6089).

The HTLU-unhealthier and HTHU groups had the largest absolute and relative reductions in taxed beverages and increased their purchases of untaxed beverages. Households with lower purchases of untaxed beverages (HTLU-unhealthier and LTLU) had the largest absolute and relative increases in untaxed beverages. We also found that among households with higher purchases of taxed beverages, the group with lowest socio-economic status had the greatest reduction in purchases of taxed beverages.

Evidence associating the SSB tax with larger reductions among high purchasers of taxed beverages prior to the tax is relevant, as higher SSB purchasers have a greater risk of obesity, diabetes and other cardiometabolic outcomes.

To describe trends across the intake distribution of total, manufactured and homemade sugar-sweetened beverages (SSB) from 1999 to 2012, focusing on high SSB consumers and on changes by socio-economic status (SES) subgroup.

We analysed data from one 24 h dietary recall from two nationally representative surveys. Quantile regression models at the 50th, 75th and 90th percentiles of energy intake distribution of SSB were used.

1999 Mexican National Nutrition Survey and 2012 Mexican National Health and Nutrition Survey.

School-aged children (5–11 years) and women (20–49 years) for trend analyses (n 7718). Population aged >1 year for 2012 (n 10 096).

Over the 1999–2012 period, there were significant increases in the proportion of total and manufactured SSB consumers (5·7 and 10·7 percentage points), along with an increase in per-consumer SSB energy intake, resulting in significant increases in per-capita total SSB energy intake (142, 247 and 397 kJ/d (34, 59 and 95 kcal/d) in school-aged children and 155, 331 and 456 kJ/d (37, 79 and 109 kcal/d) in women at the 50th, 75th and 90th percentile, respectively). Total and manufactured SSB intakes increased sharply among low-SES children but remained similar among high-SES children during this time span.

Large increases in SSB consumption were seen between 1999 and 2012 during this pre-tax SSB period, particularly for the highest consumers. Trends observed in school-aged children are a clear example of the nutrition transition experienced in Mexico. Policies to discourage high intake of manufactured SSB should continue, joined with strategies to encourage water and low-calorie beverage consumption.