Field Notes

Soda Taxes Help Change People's Minds

It wasn't that long ago when cigarettes and soda were go-to convenience store vices, glamorized in movies, and marketed toward, well, everyone.

Then, lawmakers and voters raised taxes on cigarettes, and millions of dollars went into public education campaigns about smoking's harms. Decades of news coverage chronicled how addictive and dangerous cigarettes were and the enormous steps companies took to hide the risks and hook more users. The result was a radical shift in social norms that made it less acceptable to smoke and pushed cigarette use to historic lows, especially among minors.

New University of California (UC), Berkeley research suggests sugar-sweetened beverages may be on a similar path.

The city of Berkeley's first-in-the-nation soda tax a decade ago and more recent Bay Area tax increases on sugar-sweetened drinks not only have led to reduced sales but also are associated with significant changes in social norms and attitudes about the healthfulness of sweet drinks, says Kristine A. Madsen, MD, MPH, a professor at UC Berkeley's School of Public Health and senior author of a paper published in the journal BMC Public Health.

Over the span of just a few years, taxes coupled with significant media attention significantly affected the public's overall perceptions of sugar-sweetened beverages, which include sodas, some juices, and sports drinks. Such a shift in the informal rules surrounding how people think and act could have major implications for public health efforts more broadly, Madsen says.

"Social norms are really powerful. The significant shift we saw in how people are thinking about sugary drinks demonstrates what else we could do," Madsen says. "We could reimagine a healthier food system. It starts with people thinking, 'Why drink so much soda?' But what if we also said, 'Why isn't most of the food in our grocery stores food that makes us healthy?'"

Madsen and colleagues from UC San Francisco and UC Davis analyzed surveys from 9,128 people living in lower-income neighborhoods in Berkeley, Oakland, San Francisco, and Richmond. Using data from 2016 to 2019 and 2021, they studied year-to-year trends in people's perception of sugar-sweetened beverages.

They wanted to understand how the four taxes in the Bay Area might have affected social norms surrounding sugary beverages—the unwritten and often unspoken rules that influence the food and drinks we buy, the clothes we wear, and our habits at the dinner table. Although social norms aren't visible, they are incredibly powerful forces on our actions and behaviors.

Researchers asked how often people thought their neighbors drank sodas, sports drinks, and fruity beverages. Participants also rated how healthful several drinks were, which conveyed their attitudes about the beverages.

The researchers found a 28% decline in the social acceptability of drinking sugar-sweetened beverages.

In Oakland, positive perceptions of peers' consumption of sports drinks declined after the tax increase, relative to other cities. Similarly, in San Francisco, attitudes about the healthfulness of sugar-sweetened fruit drinks also declined.

In other words, people believed their neighbors weren't drinking as many sugar-sweetened beverages, which affected their own interest in consuming soda, juices, and sports drinks.

"What it means when social norms change is that people say, 'Gosh, I guess we don't drink soda. That's just not what we do. Not as much. Not all the time,'" Madsen says. "And that's an amazing shift in mindsets."

The research is the latest from UC Berkeley that examines how consumption patterns have changed in the decade since Berkeley implemented the nation's first soda tax. A 2016 study found a decrease in soda consumption and an increase in people turning to water. Research in 2019 documented a sharp decline in people turning to sugar-sweetened drinks. And earlier this year, Berkeley researchers documented that sugar-sweetened beverage purchases declined dramatically and steadily across five major American cities after taxes were put in place.

The penny-per-ounce tax on beverages, which is levied on distributors of sugary drinks—who ultimately pass that cost of doing business on to consumers—is an important means of communicating about health with the public, Madsen says. Researchers tallied more than 700 media stories about the taxes on sugar-sweetened beverages during the study period. That level of messaging was likely a major force in driving public awareness and norms.

It's also something Madsen says future public health interventions must consider. It was part of the progress made in cutting cigarette smoking and seems to be working with sugary drinks. And it's those interventions that can lead to individual action. "If we change our behaviors, the environment follows," Madsen says. "While policy really matters and is incredibly important, we as individuals have to advocate for a healthier food system."

— Source: University of California, Berkeley

 

Dark Chocolate Linked With Reduced Risk of Type 2 Diabetes

Consuming dark, but not milk, chocolate may be associated with lower risk of developing type 2 diabetes (T2D), according to a new study from Harvard T.H. Chan School of Public Health.

"Our findings suggest that not all chocolate is created equal," says lead author Binkai Liu, a doctoral student in the department of nutrition. "For anyone who loves chocolate, this is a reminder that making small choices, like choosing dark chocolate over milk chocolate, can make a positive difference to their health."

There is an existing body of research on the relationship between chocolate and T2D but findings have been inconsistent, and few studies have differentiated between chocolate subtypes (dark vs milk).

The researchers sought to fill this gap using data from the Nurses' Health Studies I and II and the Health Professionals Follow-up Study. Over the course of 30+ years, 192,000 adult participants who were free of diabetes at the study's outset reported on their food habits, including chocolate consumption, as well as their diabetes status and body weight. By the end of the study period, nearly 19,000 of the total participants reported being diagnosed with T2D. Of the nearly 112,000 who reported specifically on their dark and milk chocolate intake, nearly 5,000 were diagnosed with T2D.

The study found that participants who consumed at least 5 oz of any type of chocolate per week had a 10% lower risk of T2D compared with those who never or rarely consumed chocolate. Dark chocolate had an even bigger impact: Participants who consumed at least five servings of this chocolate per week showed a 21% lower risk of T2D. The researchers also observed a 3% reduction in risk for every serving of dark chocolate consumed per week. Consumption of milk chocolate, meanwhile, was not associated with reduced T2D risk. Increased consumption of milk chocolate, but not dark chocolate, was associated with long-term weight gain, a potential contributor to the development of T2D.

"We were surprised by the clear split between dark and milk chocolate's impact on diabetes risk and long-term weight management," says corresponding author Qi Sun, MD, an associate professor in the departments of nutrition and epidemiology. "Even though dark and milk chocolate have similar levels of calories and saturated fat, it appears that the rich polyphenols in dark chocolate might offset the effects of saturated fat and sugar on weight gain and diabetes. It's an intriguing difference that's worth exploring more."

— Source: Harvard T.H. Chan School of Public Health