Public health advocates are cheering as an excise tax has been credited with bringing down soda consumption in one northern California city.
After a penny-per-ounce tax was levied on sugary drinks in Berkeley, a University of California Berkeley study has shown a 21% drop in consumption in some of the city’s low-income areas.
The study was published Tuesday in the American Journal of Public Health. Berkeley was the first American city to roll out a soda tax in March 2015, while similar measures failed to make it past the ballot in San Francisco and Oakland. Those cities have since seen a 4% increase in soda consumption, according to the study.
See also: Philadelphia Passes Game-Changing Soda Tax
Perhaps even more encouraging is that residents seem to be switching to water. Respondents said they drank 63% more bottled or tap water than they previously had, while residents of Oakland and San Francisco indicated only a 19% increase.
Only 2% of Berkeley residents said they actually made the trek across city lines to buy tax-free soda.
“Not only was the drop in sugary drink consumption in Berkeley greater than we expected, the apparent shift to less harmful products like water is a very good sign,” said Kristine Madsen, an associate professor of public health at UC Berkeley who co-authored the paper.
See also: What the Soda Tax Means for Consumers
To carry out the study, researchers said they surveyed 2,500 people “in low-income, high-foot-traffic commercial areas of Berkeley, Oakland, and San Francisco.”
Their methodology was criticized by Brad Williams, an economist who consults for the American Beverage Association. Man-on-the-street surveys are “inherently unreliable,” he told The Wall Street Journal.
Madsen said her team is “looking for tools that support people in making healthy choices, and the soda tax appears to be an effective tool.”
“While Berkeley is just one small city, this is an important first step in identifying tools that can move the needle on population health,” she added.
