When the city of Berkeley, California, considered a soda tax in 2014, the soda industry spent more than $1.6 million trying to convince voters that it was a bad idea. The campaign didn't work, and the tax passed. Now—while the industry sinks another $9.5 million into ads in nearby San Francisco, Oakland, and Albany—a new study shows how Berkeley's tax has worked so far.
The study, from researchers at the University of California-Berkeley, shows that sales of soda and other sugar-sweetened beverages have dropped 21% in low-income neighborhoods in the city since the tax went into effect.
"I think that there's a lot of interest in this because there's a big debate around the value of taxes," says senior author Kristine Madsen. "We're certainly not pro-tax; we're pro effective public health tools, and we're really interested in the evidence in what seems to be most effective in helping people choose healthier foods in general and healthier beverages."
The researchers surveyed shoppers on the street in low-income neighborhoods both before and after the tax; data from stores wasn't available. "The corner stores, which are really prevalent in low-income neighborhoods, rarely have electronic data, so it's really hard to get objective data," she says. "Those few stores that do are usually not interested in sharing."
While people reported drinking fewer sugary drinks in Berkeley after the tax, others in Oakland and San Francisco reported drinking slightly more. Berkeley shoppers also reported drinking 63% more tap water or bottled water after the soda tax.
As San Francisco and Oakland consider similar taxes now, industry ads have positioned the policy as a "grocery tax" on poor people. "It's completely inappropriate...the tax is only on sugar-sweetened beverages," says Madsen. "I appreciate that the industry is nervous about losing market share, but that is not how they should be prioritizing their messaging. They need to be moving towards healthier products rather than trying to really undermine efforts by using false language."
The tax targets soda distributors, who can decide whether or not to pass it on to retailers. Retailers can choose to spread the tax out among other items, but that's not the intent of the policy. In Berkeley, researchers previously found that the tax did boost soda prices, not the cost of food in general.
The new study doesn't prove that the tax was solely responsible for the change in habits—it's possible that public health campaigns have also had an impact. Future studies may make that link clearer. But if the rate of decrease can be sustained, it's likely to truly change public health.
Drinking a can of soda a day, with 22 teaspoons of sugar, is roughly equivalent to gaining 15 pounds. "If you reduce that by 20% across the population—we're talking millions and millions of pounds—this actually has the potential to have a huge public health impact," Madsen says.
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