More evidence to back a sugar tax to prevent obesity and diabetes has emerged from Mexico, where a tax on sugar-filled drinks has helped reduce consumption over three years.

In 2014, Mexico implemented an excise tax of 1 peso per litre (approximately 10% increase in price) on sugar sweetened drinks aimed at reducing consumption.

The move has already been shown to be associated with reductions in household purchases of sugary drinks, but now a new study published in the BMJ has also shown benefits at an individual level in reduced consumption related to the sugar tax.

Researchers assessed sugary drink consumption in 1770 Mexican health workers from 2004 to 2018, covering the periods before and after the tax was implemented.

Participants self reported their food and drink consumption over the previous 12 months, and were categorised as either a non-consumer, low consumer (less than one serving of 355 mL a week), a medium consumer (at least one serving a week but less than one serving a day) or a high consumer (at least one serving a day).

After the implementation of the tax, the probability of becoming a non-consumer increased by 4.7 percentage points, and the probability of being a low consumer increased by 8.3 percentage points.

What’s more, the probability of being in the medium and high levels of soft drink consumption decreased by 6.8 percentage points for medium consumers and 6.1 percentage points for high consumers.

Stronger associations were seen in participants with secondary school and higher education than in those with elementary school or less.

The study investigators cautioned that the results were from an observational study and from a health worker’s cohort that may not reflect the behaviour of the general population.

Nevertheless, they believed the findings together with other published evidence, “indicate that a fiscal measure such as taxation can be effective in helping to reduce intake of sugar sweetened drinks in the population.”

“These results have an important public health implication, as they add to the much needed evidence for the short term and longer term effects of sugar sweetened beverages taxation on sales and consumption that has been requested by policy makers and industry stakeholders.

“Our findings show the continuous role that taxation might play in reducing intake of soft drinks three years after implementation. Further research to understand the longer term implications that these changes could have for body weight or metabolic diseases is needed,” they wrote.

Meanwhile, the success of the sugar tax in Mexico has led to calls to increase it to 20%, to further reduce consumption of unhealthy drinks.