Warning consumers away from sugary drinks

In the ongoing battle against excess sugar - identified as a contributor to a national epidemic of obesity, diabetes, and tooth decay - research at the University of Pennsylvania shows that warning signs on the labels of sugary beverages hold promise.

The project, led by Christina Roberto, an assistant professor of medical ethics and health policy at the Perelman School of Medicine, found that parents may be much less likely to buy a sugar-sweetened drink for their children if there were warning labels, versus no labels, or even labels specifying the calorie count.

The results were published in a recent edition of the journal Pediatrics, one week after the U.S. Department of Agriculture issued new guidelines recommending that added sugar - as opposed to the sugar already in, say, a piece of fruit - should be limited to 10 percent or less of a person's daily caloric intake.

Roberto spoke to us recently about the research, funded with a $35,000 grant from the Robert Wood Johnson Foundation.

With added sugar in so many foods, why focus on sugar-sweetened beverages?

There has been rising concern about the intake of sugar-sweetened beverages, and policymakers are interested in doing something about that. Bills have been introduced in California and New York. In San Francisco, officials were interested in putting warning labels on advertisements for sugary drinks, instead of product containers. Most recently, Baltimore officials also announced that they are interested in pursuing a bill to put labels on sugary drinks.

The one question that comes up a lot is, why single out sugar-sweetened beverages specifically? Obesity is a complex problem, and certainly there are a lot of factors that contribute to it.

But there are lots of reasons. First, sugary drinks are the largest sources of added sugar in the American diet. Also, we now have a growing body of research that links sugary drinks with a number of health consequences - weight gain, diabetes, tooth decay.

The other interesting and unique thing about sugary drinks is that, really, all of the calories are just coming from sugar. They don't offer any other nutritional benefits. Whereas other foods - think about a Snickers bar - might have a lot of calories, but at least you're getting some benefit from the nuts.

The fourth reason: There is some research to suggest we don't compensate for calories from liquids the way we do from solid foods. If you have a lot of calories at lunch, you might not eat as much as dinner. But sugary drinks may be different. That is an emerging worry.

What did the study involve?

When the bills I mentioned before were introduced, there wasn't really a lot of data on how these warnings might impact consumers. We wanted to take the very first step to understand it.

We recruited 2,381 parents for an online study. They had to imagine they were out shopping with their kids, and they had to decide what kind of drink to buy from a vending machine. We had the usual range of offerings - sugary drinks, drinks with less sugar, and drinks with no sugar.

We randomized the parents to view no labels, calorie labels - right now, the American Beverage Association prints calories per bottle on the labels - and then had four different versions of a warning label.

And the results?

Basically, what we saw is that when there were no labels, about 60 percent of parents chose a sugary drink for their kids. When calorie labels were on there, 53 percent of parents chose a sugary drink. Statistically, that wasn't significantly different from the control group. But when the warning was on the label, that number dropped to 40 percent. The warning label - regardless of the specific wording - had a big impact on that choice.

We think there are two reasons why the labels might shift behavior. Some would say, "Doesn't everyone know that soda has a lot of sugar in it?" But research shows that although many people know a can of soda has a lot of sugars, many people don't know that other beverages, such as sports drinks, certain flavored waters, or fruit drinks, also have a lot of added sugar in them.

There's also the idea that parents do have that information, but the warning label provides a reminder at the moment.

Were any results particularly surprising?

I was surprised by how many people supported the warning-label policy - 73 percent. It was true across political affiliations - 73 percent Republicans, 66 percent independents, and 79 percent Democrats.

Some policies can be controversial, and this seems to be one that has broad appeal. I do think consumers tend to be more in favor of policies that are about educating people and arming them with the information they need to make healthier choices.

What does this study suggest about Philadelphia's failed proposal to tax sugary beverages?

What this study suggests is that the warning-label policy might have beneficial effects, and we should gather more data. One way would be to implement the policy in a small city and gather real-world data. That would help show if we should pursue this on a national level.

But obesity is a complicated problem, so no one policy is going to fully address it. We think about warning labels as one tool to try to improve the quality of what people are eating. Taxes would be another one. Restrictions on food marketing would be another. For example, in the United Kingdom, food has to meet a certain nutritional standard to be advertised on children's television programming. Instituting school policies that increase the quality of food in schools is another tool. Many need to be pursued to get a handle on obesity.

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