Harvard research shows soda tax might work

Bottles of soda with strawThe debate over whether or not a tax on soda and other sugary drinks would actually discourage people from drinking them has been going on for some time. People who support the idea often point to alcohol and tobacco taxes as examples of how price increases for health-harming products can reduce their use. Anti-soda taxers say that comparing soda to things as harmful as booze or cigarettes is inaccurate, and question whether a soda tax would unfairly target specific populations.

But amidst the points and counterpoints, name-calling and finger-wagging, researchers at Harvard Medical School/Harvard Pilgrim Health Care conducted a real-life study at Brigham and Women’s Hospital to see if a soda tax would help reduce soda consumption. And as it turns out, it did.In an intervention staged by researchers to try to measure the effectiveness of a soda tax, one of the hospital’s cafeterias saw soda sales slump by 26 percent, after a 35 percent tax on all regular, full-calorie soda was enacted. The sale of reduced or calorie-free diet sodas, which wasn’t taxed, rose by 20 percent during the taxation period.

“The concept of a soda tax is very controversial here in America and it’s an issue that has yet to be resolved” says John Block, MD, of Harvard Medical School’s Department of Population Medicine, and lead author of a paper that reported the study’s findings in American Journal of Pediatrics. “The implications of our study are that price intervention may be an effective strategy towards a reduction in soda consumption and it should be part of the conversation when you discuss whether or not taxes can have legitimate effect in public health policies.”

John Block, MD
John Block, MD

One of the most intriguing findings from the study showed that, unlike changes in price, educational information about soda and obesity didn’t seem to influence consumers. During a portion of the study when soda was being taxed, researchers posted fliers in the cafeteria that let diners know by skipping just one regular soda a day they could lose up to 25 pounds a year. Results showed that educational information didn’t seem to affect soda sales. Block says that data was one of the study’s more surprising findings.

“There didn’t seem to be any clear independent effect from the educational intervention aspect of the study,” he says. “That’s not to say that education doesn’t work, it has to be tested in a variety of different ways, but still that aspect was surprising to us.”

While Block says the results of the price intervention study prove that there could be merit in imposing a soda tax to reduce soda consumption, he’s not sure the country is fully ready to embrace the idea.

“There are a lot of issues that come up when you talk about taxation. In terms of settled policy, the idea of taxing cigarettes or alcohol is something we’ve come to terms with in this country but I don’t think we’re there yet for soda,” he says. “But the argument will come up more and more now that there is such national momentum surrounding childhood obesity and I think the idea of a soda tax should be on the table. I’m not sure it’s necessarily the correct strategy, but I think it’s worthy of debate.”

Boston has also launched a Soda-free challenge this summer.