A new estimate of the health impact of soda taxes in Mexico sheds some light on what's at stake in ballot measures coming to a vote in three Bay Area cities and Boulder, Colo. next week. In cases of heart disease and diabetes averted, the model suggests that, in Mexico, those levies are on track to save close to a billion dollars and powerfully improve lives.
After a tandem run-up in consumption of sugar-sweetened beverages and obesity, Mexico has become one of the fattest countries on Earth. In 2014, it adopted a 10% excise tax on the sale of sugary drinks.
The beverage producers claimed that soda taxes would do little to reduce consumption. But market surveys show that Mexicans reduced their purchases of sugar-sweetened beverages by an average of 6% in 2014 per household.
And by December 2014, that drop in purchases was at 12%.
If Mexicans sustain this pattern of consuming fewer sweetened beverages, the model developed by researchers predicts that over 10 years, the 10% excise tax could prevent 189,300 new cases of Type 2 diabetes, 20,400 strokes and heart attacks, and 18,900 deaths among adults 35 to 94 years old.
From 2013 to 2022, the reductions in diabetes alone could yield savings in projected healthcare costs of $983 million dollars, the researchers concluded.
Among the largest beneficiaries of these tax-related health benefits are Mexico's substantial population of younger adults — those 35 to 44 — whose consumption of sugar-sweetened drinks is the highest. In this group, half of the new diagnoses of diabetes projected for the study's 10-year period could be averted. That same group would see the greatest reductions in coronary heart disease diagnoses as well.
On the whole, men — who in 2012 consumed close to nine servings per week of sugar-sweetened beverages — would see the greatest health gains from the 10% excise tax, the researchers concluded. Women, who consumed about six servings a week before the tax was levied, would see more modest health improvements.
The model was devised by a team led by UC San Francisco internal medicine specialist Kirsten Bibbins-Domingo and reported this week in the journal PLoS Medicine. In their projections, the researchers assumed that Mexicans would compensate for their reduced sugary-drink consumption by taking in 39% of those lost calories in some other form, such as milk.
Its projections of the health impact of Mexico's soda taxes are "likely conservative," the authors of the model write. While the model predicted the taxes' effects on adults older than 35, Mexico's fast-growing population and the country's heaviest citizens — also its heaviest consumers of sugary soft drinks — are younger than that.
As this younger generation ages, the impact of reducing their sugar intake — and close to half of added sugars come from sweetened drinks, experts say — could dwarf predictions pertaining to their elders.
If some combination of excise taxes and other public health measures could drive sugary soda consumption down further — by 20% of 2012 consumption levels — the model predicted that diabetes diagnoses would drop by 9.5% for a total savings of nearly $1.9 billion dollars.
Whether Americans would respond to a tax on their sugary drinks as Mexicans have is open to debate. Unlike in Mexico, where the soda tax is national and consumers cannot travel to neighboring towns to avoid it, Americans have resisted such taxes.The beverage industry and its allies have quashed or defeated many soda-tax proposals at the state or federal level. So soda-tax initiatives have largely been taken up at the local level.
Next Tuesday, California voters in San Francisco, Albany and Oakland and those in Boulder, Colo., will vote to levy taxes on the sale of sugar-sweetened drinks. If backers of those initiatives succeed against fierce opposition from the $73-billion soda industry, those cities will join Philadelphia and Berkeley, Calif., in imposing such taxes.
According to Healthy Food America, a group that advocates for soda taxes and other anti-obesity measures, soda taxes adopted in the Bay Area could drive down soda consumption by 20%, prompting a 4% drop in new cases of diabetes after a few years. They could reduce cases of obesity by 6,000 by the end of 2025 and yield healthcare savings of $54.9 million over 10 years.
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