Many policies have been proposed and enacted to help improve public health by changing their diet and preventing obesity. Among the most prominent, our efforts to reduce consumption of sugary beverages, ranging from programs that educate consumers about risks to the most dramatic approach: taxing such beverages. Evaluating these other policies is critical and understanding how governments can best move ahead. Leading the charge was such evaluation as our guest today on the Leading Voices in Food Dr. Christina Roberto from the University of Pennsylvania.
Christina Roberto joined the faculty at the Perlman School of Medicine at the University of Pennsylvania in 2015 having served previously on the faculty at the Harvard School of Public Health. She's a highly productive scholar, having done pioneering work on, for example, evaluating the impact of placing calories on restaurant menus in front of package labeling schemes and other policy interventions and has another entire body of research on eating disorders. Christina received joint Ph.D. Degrees in psychology and epidemiology from Yale University.
You run the Psychology of Eating and Consumer Health (PEACH) Lab at Penn. Would you explain some of the work you're doing with your students and colleagues?
Sure, so the mission of the PEACH Lab, as we call it, is to identify policies and interventions to promote healthy eating. And we work across six broad areas. We think a lot about the psychology of eating and along the lines of how do you design nutrition information so that it's really accessible to people. We do work on the economics of eating - so thinking about beverage tax policies and the influence they have some work around culture and eating. Issues like why does a country like Japan have a 4% obesity rate and other countries have 30%, and then some work around mental wellbeing with a focus on eating disorders. And, we're moving more and more into questions around planetary health - so win/wins like reducing red meat consumption, it's good for people's health, but it's also good for the planet's health. So we really work across a broad range of areas.
You received a large grant to study sugar-sweetened beverage intake Guatemala. So it's well known in the United States about the high risks of sugary beverage consumption and the high rates of consumption, but what's the picture in other countries and why would Guatemala be of particular importance?
Guatemala is a really, it's an interesting country. So it's a classic example of the double burden of disease. So, on the one hand, you have 47% of kids have childhood stunting that's due to malnutrition. And then you've got 30% of kids increasingly struggling with overweight and obesity. And so Guatemala is a country where they're on this really worrisome upward trajectory where you get these rising rates of obesity, even in the context of malnutrition. And so people are really concerned and really starting to think about policy changes there to try to prevent them from continuing on this. And in terms of sugar-sweetened beverages, there's not a lot of data from Guatemala, but there is some survey research that suggests that about 80% of kids drink a sugar-sweetened beverage at least once per week. So it's obviously a prime target to want to change behavior around that on the sooner side.
So what does your project involve?
We've been working with a team in Guatemala, a terrific group led by Joachim Barnolia, and the project has two goals. So the first one is to do a field experiment where we would test a policy of placing warning labels on sugary drinks in school stores. So we would randomize different schools, two different kinds of labels and then try to understand how those labels would influence the types of drinks kids are purchasing at the school store. And we're testing labels like text-based warning labels that literally would say something like drinking beverages with added sugar, contributes to obesity, diabetes and tooth decay. And then we're using some graphic images. So what happens if you display the teaspoons or sugar cubes of sugar. And then we're going to test a symbol that's very similar to the symbol being used in Chile--sort of a stop sign like symbol that would just alert consumers to the high amounts of sugar. We'll be able to look at kids' purchases, and we'll also do some survey work with them to see if this is a policy that might really be able to move the needle on behavior.
So there are a lot of things one could possibly do to reduce sugary-beverage consumption. You're talking about warning labels. One could also imagine broad education campaigns through the media. One could imagine taxes. Why have you chosen the warning labels as a place to start?
So it was a combination of, um, something that we did think would be impactful but also feasible. If you ask me right now to list the number one policy you could pick to try to move the needle, I would tell you taxes. But I think working with local partners has been really critical and they felt like there might be an opportunity policy wise around labels and that we'd really need an evidence base. And I do think something like a warning label has different psychology to it than just a typical food label. We've learned that the word warning really comes with a sort of an extra, an impactful punch when you're trying to get a message out there. So I'm quite curious about these labels and think they could be pretty promising.
So is there a certain segment of the population you think might be most responsive to labels? Would it be parents, older adults, younger adults, children? What do you think about that?
The Devil's in the details with labels. There are definitely ways to design labels where they can have a broader reach across the whole population. It's pretty well established that when you're talking about a label, like the standard nutrition facts label we see in the US, that has lots of numbers and percentages and lots of information, you tend to get higher socioeconomic status folks using them and then lower socioeconomic status folks not using them. And so, the wave of new kinds of labels where you're talking about traffic lights or stop signs or these really intuitive symbols - the hope, we don't have very good on it yet, but the hope is that that's going to cut across a broader segment of the population and really resonate with most people.
You mentioned some numbers about how frequently beverages, sugary-beverages are consumed by children. But why pick sugary beverages as the target for warning labels? Are there other parts of the food supply that would have been logical candidates as well?
I think sugary beverages are really a special product and there's a special case to be made to focus on them specifically. So certainly in the US, we see that they're the largest source of added sugar in the diet. There are data to suggest that when you drink calories in liquid form, it doesn't keep you as full than if you eat the same number of calories in solid form. And so I think that makes them uniquely problematic. And they just have no nutritional value, right? So, it's pretty much all coming from sugar where you could imagine even some candy bars have nuts in them or sort of other redeeming qualities. So I think for all those reasons, plus the really strong scientific evidence base that links them in particular to weight gain suggests that it just makes a boatload of sense to focus on them.
Has the industry in Guatemala, the beverage industry, started in the mobilize against these policies?
It's interesting. I mean, these are multinational companies, and so they're obviously working across the globe in a variety of ways to try to, for all intents and purposes, undermine these policies. I think part of the reason you haven't seen much action in Guatemala is some worry about that. But I will say Latin America is a really interesting place right now for food policy because some of the most progressive, interesting work is happening on the policy front. And Chile is a good example of that where they've done food marketing restrictions and taxes and really aggressive labeling. So a lot's happening there, and we really need to pay attention to what they're doing and evaluate it.
So a little closer to home, another major project you have underway is the evaluation of the soda tax in Philadelphia. In an earlier podcast, we had Dr. Thomas Farley, the health commissioner in Philadelphia, as a guest and he explained the rationale for the tax and answered some of the same questions you have on why soda for example. He outlined the structure of the tax and the industry response, which has been considerable. What are you learning about the impact that tax?
We've been doing this fairly large evaluation that's funded by Bloomberg Philanthropies where we're able to study the tax from a bunch of different angles. And the first component is looking at what's happened to tax beverage sales and large chain retailers. So supermarkets, fast merchandisers, and pharmacies where beverages are being sold. And we have some really, I think important and exciting results. So there are two issues to think about with the tax. The way it's structured in Philadelphia is that the tax is on distributors. And so what that means is that a distributor and makes a decision of how much of tax to pass on to a store and then the store decides how much of that tax to pass onto the consumer. And the store could absorb all of the tax, or they could pass it all on, and there would be really considerable price increases.
And so the first thing we've learned from our evaluation is that that the passthrough has differed based on the store types. So in supermarkets, about 43% of the tax has been passed on. It's 58% of mass merchandisers, and pharmacies have actually passed on 104% of the tax. So we're seeing the biggest price increases there. Now what we're really interested in is how that translates into volume sale reductions. And so what we're seeing in our data is that overall there's been a 51% reduction in the volume sales of tax beverages in Philly. And this is when you do a natural experiment. So we have a control site in Baltimore so we can be really confident in these results. Now there is one other piece to this story, which is something called cross-border shopping, right? So when you tax things, they're going to be some people who hopped the border and try to buy products over there. And we do see some of that. But only about a quarter of the taxes offset by that. So at the end of the day, we see reductions over the city of about 38% of tax beverages. And the last piece is you get some variability across store types. So the biggest effects are in supermarkets. It's a 59% drop there. It's 40% mass merchandisers, and then a little bit smaller, it's 13% in pharmacies.
So that's counterintuitive because the pharmacies passed along more tax than the other places. Why do you think that's happening?
Yes, exactly. So when we dig into the data, what we see is that the real action here, and what's really changing, are the larger size beverages. So your 2-liters, your 12-packs or 24-packs--that's where, and it makes sense, their price increase is more salient. And so that's what's driving a lot of this effect. And pharmacies are selling many fewer of those types of large-sized beverages. You see that much more in supermarkets. And so we think that's what's explaining that difference.
With the tobacco companies, as tobacco taxes have been raised a number of times, over the years, there have been occasions where the tobacco companies have actually passed along a higher increase in price than what the tax would dictate. Like the 104% you mentioned for pharmacies. Why don't you think the soda industry has done that? Do you think that deferring taxes across venues will even out over time because consumers will just learn where the soda is cheaper?
We've got one year of data, and obviously, it's curious to see what happens beyond that. We're going to look at two-year results. We know the past through occurs pretty early on, sort of very soon after January 1st and starts then. And so at least our one-year long term data suggests they are holding pretty stable at these price increases. So I don't know if that would even out over time. And yes, you do sometimes see this over shifting in economic terms where some places capitalize on it, and they just raise prices even more. It is interesting on the ground in Philly because a lot of retailers have put signs up basically saying to consumers - 'Look don't blame us, this isn't our fault. Your soda is more expensive because of the tax.' And so I think part of the reason they didn't pass all of it on all of the tax is there was a real worry of losing customers, of losing revenue, and that they were a little hesitant to do that. I do think there's kind of a potentially interesting effect of the signage that it actually makes the tax more salient. And so I wonder if that might boost the behavioral impact of it.
Something that some individuals had predicted would happen has come true, according to Tom Farley in that the soda industry has not been able to fight the taxes in the courts and in other ways. So they are now putting money into political campaigns so they can try to shift over the composition of the city council in hopes that they can vote down a tax. Do you have any sense of where that stands, how the public is reacting? Is it clear who the soda companies are supporting and not, and how's that playing out?
I don't have a sense about how it's ultimately going to play out. So certainly, you know, that's happening, and there's a worry about it. I do think it's mixed. It really depends who you talk to, right? So there are store owners who really don't like the tax, but we do survey work with people, and oftentimes when they hear that their revenue is being used to expand Pre-K, that can really shift people's thinking on the tax. So their first reaction is, oh a tax, I don't like it. Oh wait, this is being used to really help some very low-income areas in Philadelphia and expand education opportunities? And people tend to get behind it for that reason. And so I think that's part of the reason it passed, that there is a lot of support and enthusiasm for that particular goal. And that might really help people running for city council to make that case for the importance of this tax sort of irrespective of this other public health effect that it likely has.
So then there could be a strong political price to pay for anybody who wants to repeal the tax if the consumers and the citizens are valuing the use of the revenue.
Yes, absolutely. I think that's right.
As you think ahead to the future of policies to prevent obesity and to improve diet overall, what do you think are some of the ways things might go? If you could fast forward five years, what do you think the picture might look like?
I think there's a lot of promise and a lot to be hopeful for because I think we're starting to see action. Particularly if you look at this in a global way. I think everyone who works in this space feels like there is no one policy that's going to solve this problem, and that we really need a suite of policies. And I think you have examples of certain countries which are now finally doing that. And so I think as you get some success stories like a country like Chile, as some of these beverage taxes have success, I think that kind of data could be very persuasive. And we'll start to see ripple effects of lots of places doing labeling, doing these kinds of tax policies. And also, not just the policy front but sitting down with industry and making plans around reformulation. We've got the national salt reduction program in this country. The UK has done some of this and engaging across sectors. I think we just hope that something like beverage taxes that has stalled out a little bit in the US, and so I hope that once some more evidence comes out that that'll pick up again. I think there's a lot to be excited about, you know, and, and happening in the next five years.
You mentioned reformulation. Do you think if a food industry, for example, gradually reduced the salt across a number of products or within a category like soup, for example, do you think consumers can get used to having less salt, less fat, less sugar, and things?
Oh, absolutely. I mean, I think it's pretty well documented that with sodium, in particular, consumers can get used to it. And then there are benefits to not necessarily advertising that it's happening. It was funny, I was talking to a colleague in the UK where they have lower sodium levels, and he says every time he comes over here, the food is just so salty and he can't stand it. I do think there are exciting ways to do this and there are folks also working on the sugar front to figure out can we do it with sugar as well.
Do you think it's best to let consumers know these shifts are happening or not?