Will a tax on sugary sodas force people to start drinking more healthy drinks?  Evidence from Mexico seems to suggest that it will, particularly among the lower socioeconomic groups in the country.

Mexico adopted an peso-per-liter tax on sugary drinks beginning January 1, 2014, and a new study says the tax is associated with an average decline in consumption of sugar sweetened beverages of six percent after one year, according to a report on medpagetoday.com.

The evidence is also suggesting the decline is growing, with a 12 percent decline noted in December of 2014, as compared to what would have been purchased had the tax not been implemented, says Shu Wen Ng, PhD at the University of North Carolina Gilings School of Global Public Health in Chapel Hill and his research colleagues.

The authors of the study looked at data from Nielsen Mexico’s Consumer Panel Services for the period of January 2012 through December 2014, including households in 53 Mexican cities.  Consumption of the beverages decreased across all socioeconomic groups, but the lowest group recorded the biggest drop at nine percent for the year and a 12 percent decrease in December.

The drops in consumption were greater in non-carbonated drinks when compared to carbonated drinks, causing the authors of the study to theorize since non-carbonated drinks are often more expensive, they were more easily replaced.

The group pointed out that about 70 percent of adults in Mexico are either overweight or obese, with a high prevalence of diabetes in the country, and the reduction in sugary drink consumption would likely have an affect on those rates over time.

The researchers cautioned their study was done only in cities that had a population of 50,000 or more and data on dairy drinks was incomplete prior to October of 2012.  The team added they believe the reductions would be even more dramatic in rural households, but without actual data, that was purely speculative.

They also said the purchases of sugary drinks at a restaurant or from a street vendor were not recorded in the survey data as well.

In the United States, the city of Berkeley, California, is the only area that has adopted a sugar tax.