A survey of more than 2,500 adults living in low-income, high-foot traffic commercial areas of Berkeley and neighboring cities of Oakland and San Francisco conducted over the course of a year before and after the tax was enacted revealed the “greater than expected” drop, according to the study published Aug. 23 in the American Journal of Public Health.
The decrease is even more notable when compared to the 4% increase in consumption of sugar sweetened beverages in Oakland and San Francisco, which do not have similar excises taxes on the beverages, despite failed attempts by San Francisco to follow Berkeley’s lead.
The drop also is significantly higher than those observed in other countries with similar excise taxes.
In Mexico, for example, a 1 peso per liter excise tax on sugar sweetened beverages, which is equivalent to about a 10% price increase, resulted in a 12% reduction in purchase of taxed beverages.
Likewise, France saw a 6.7% reduction in demand for regular cola in the first two years after it enacted an 11 euro-cent per 1.5 liter excise tax on sugar sweetened beverages, which is equal to about a 6% price increase, according to the study.
Will the impact last?
The strong initial success of the excise tax, which works by increasing the price of sugar sweetened beverages paid by consumers after being “passed through” by manufacturers, could decrease slightly overtime and will require long-term monitoring to assess impact, acknowledged the researchers.
They explain, “The magnitude of our results may also reflect an early reaction to the tax that could rebound and settle closer to a 10% reduction in consumption.”
However, they add, “Mexico’s reduction in SSB purchases increased over the year following the tax.”
They also acknowledge the risk that consumption may appear lower than in reality if consumers simply are going to cities without an excise tax to buy sugar sweetened beverages.
This likely does not account for a significant portion of the current drop, through. The researchers point out that only 2% of the Berkeley residents polled reported buying sugar sweetened beverages outside the city intentionally to avoid the tax.
The impact of social awareness campaigns
The drop in consumption might not all be due to the higher prices for the tax, the study acknowledged.
Rather, it could also reflect the effects of the campaign surrounding the tax, “which may have shifted social norms and thus reduced consumption,” according to the study.
It explained, “Campaign messages focused not only on health harms of SSBs, but also on inappropriate behavior by the SSB industry. Campaign exposure, knowledge that the tax passed by a high margin (76%) of voters, or awareness of widespread support for the tax may have altered social norms.”
The researchers add that they can’t draw firm conclusions, however, because they did not assess social norms in this study. They suggest this would be good for future research.
They also suggest future research look at the beverage industry’s response to evolving consumer demand to fully understand the potential public health impacts.
Consumers reach for more water
The study also revealed that consumers’ shift away from sugar sweetened beverage is associated with a substantial uptick in purchases of bottled water, which they deemed as a “very good sign.”
Berkeley residents surveyed reported a 63% increase in drinking bottled water or tap water, while residents in Oakland and San Francisco reported a 19% rise in water consumption.