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The first tax in the country on sugar-sweetened beverages appears to be working. It went into effect last year in Berkeley, Calif., and a new study says consumption of sugary drinks at least in some neighborhoods is down enough that it could reduce the rates of obesity and diabetes. NPR's Dan Charles reports.
DAN CHARLES, BYLINE: In the fall of 2014, voters in two different cities on opposite sides of the San Francisco Bay were seeing TV ads on behalf of ballot proposals to tax sugar-sweetened drinks. It would be one extra penny per fluid ounce of regular soda or sweetened juice.
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UNIDENTIFIED MAN: Just one soda a day leads to an average weight gain of ten pounds a year. But just one cent of tax can help reduce consumption, childhood obesity and Type 2 diabetes.
CHARLES: And meanwhile, Kristine Madsen from the University of California, Berkeley, was getting ready to measure whether such a tax would make any difference. She and a small army of collaborators were out on the streets asking questions. They targeted low-income neighborhoods in both cities.
KRISTINE MADSEN: We asked about how often they drink various beverages.
CHARLES: And they waited for the vote. The tax did not pass in San Francisco, but it did in Berkeley. So sugary drinks became more expensive in one city, not in the other one. Madsen and her collaborators went back to the same neighborhoods with the same questions.
MADSEN: How often do you drink regular soda like a Coke or a Sprite?
CHARLES: Before the vote, the answers had been very similar in both cities. The average person drank about one and a quarter sugary beverages per day. But now in San Francisco where there was no tax, people said they were drinking slightly more sugary beverages. It was a hot summer.
In Berkeley, though, reported consumption of sugar-sweetened drinks went down by 20 percent. Madsen says that would be enough to reduce rates of obesity and Type 2 diabetes in years to come.
MADSEN: This would have a huge public health impact if it were sustained.
CHARLES: She's not sure it will be sustained. People may have reacted more to the tax when it was just new. Her study appears this week in the American Journal of Public Health. John Cawley, a professor of public policy and economics at Cornell University, says a 20 percent drop is more than economists would have predicted.
JOHN CAWLEY: It makes complete sense that when prices go up, people buy less. That's the law of demand, and so I did expect to see some kind of decrease in consumption. But this is a very large decrease.
CHARLES: Cawley says it'll be interesting to see if these results are confirmed by other kinds of data - for instance, from retailers. Dan Charles, NPR News.
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