Study: Seattle's sweetened beverage tax shows reduction in BMI

Study of Seattle's sweetened beverage tax shows reduction in BMI among children

The contentious sweetened beverage tax in Seattle is proving to show healthy results.

SEATTLE - The contentious sweetened beverage tax in Seattle is proving to show healthy results.

The tax took effect in 2018. It was designed to cut down on consumption of sweetened drinks and use the funds to help local families by expanding access to healthy foods and early learning programs.

A study was conducted by researchers with the University of Washington, Seattle Children's Hospital, and Public Health-Seattle and King County. The researchers found a reasonable reduction in body mass index (BMI) among children because of the sweetened beverage tax.

"The tax in Seattle seemed to be associated with a greater decline in BMI for children exposed to the tax by living in Seattle compared to a well-matched sample of children living in the surrounding cities that do not have a tax," said Jesse Jones-Smith, a professor at the University of Washington’s School of Public Health, and lead author of the study.

The sweetened beverage tax was not a sales tax charged directly to consumers, but rather a tax on distributors to pay more money per ounce for sugary drinks. However, distributors put the cost and burden back onto customers by raising prices. Business owners said this caused sales of juices and sodas to fall flat.

"I feel every single day my sales are declining because people stop buying drinks," said one store owner in Seattle during a news conference in 2018.

Sammy Abera and his family have owned a convenience store in Seattle’s Central District for more than 20 years. During a visit to the store in 2018, Abera said, "I’ve noticed a decline. More and more people are shopping outside city limits and not actually going to small corner stores like we have here, because I mean they can get it a lot cheaper."

Questions arose about if the tax could indeed make an impact on the future of public health. Jones-Smith and other local researchers put it to a test.

"Children, and particularly adolescents, are some of the largest consumers of sugary beverages. So, we first thought that we might see an impact on children more so than adults just because adolescents have such high consumption of sugary beverages," said Jones-Smith.

From August 2022 to March 2024, researchers studied 6,313 children in Seattle and neighboring cities.

"We used advanced statistical techniques to make sure we got a very well-matched comparison sample. So, we looked at kids who were basically trending on the same level in BMI. So, they were growing at the same rate in BMI before the tax, and then we look at how their rates differed after the tax," said Jones-Smith.

Jones-Smith said the research suggested the tax was associated with a reasonable reduction of body mass index in kids. Researchers said this information could be lifesaving for children if addressed early, as BMI is associated with serious health consequences.

"BMI has been so closely tied to increased risk of other chronic conditions like diabetes, and as you mentioned, getting diabetes younger. We used to rarely see diabetes in children, and now it’s just become way more prevalent, and this is highly related to the obesity epidemic," said Jones-Smith.

Researchers said BMI is also triggering menstruation cycles at a much younger age for girls.

Jones-Smith said they are currently conducting the same study among adults in Seattle. They hope to publish the results within the next year.