Why Making Healthful Foods Cheaper Isn't Enough
Bucks for broccoli or cash for carrots? Financial incentives aimed at encouraging healthier choices are catching on from New Zealand to the Philippines. Workplaces in the United States have been offering incentives for weight loss. In a London-based study, dieters got paid when they dropped pounds. Now researchers are interested in understanding how food price manipulations may influence what ends up in mothers' grocery carts. Does increasing the cost of sugary items mean fewer people buy them? Would more people buy veggies if they were more affordable?
To create successful incentives, says Yale behavioral economist Dean Karlan, a policy needs to specifically target the people whose behavior its trying to change. "So in the case of broccoli you'd want to find out who's not eating broccoli and then pay them to eat it," he says. You don't want to necessarily make broccoli cheaper for those who are already buying plenty of it, you want to target those who don't buy enough fruits or vegetables. It could be very tricky to structure such an incentive.
To find out how prices influence choices, researchers at the University of Buffalo set up an experiment where they could control food prices and see how shoppers responded. For their study, they recruited a bunch of moms to shop for groceries in the simulated supermarket and gave them each the same amount of money. In the first shopping trip, the food prices were identical to what was being offered at the local grocery chain.
But then the researchers manipulated prices several different ways. First they discounted the prices of healthful foods — making items such fruits and vegetables much cheaper. They tried a 12.5-percent discount, then a 25-percent discount.
"Then we looked at the purchasing patterns of these mothers," explains Len Epstein, a professor of pediatrics at the University of Buffalo who was involved in the study. He says the mothers' choices were somewhat predictable. When the costs went down, "they did buy more of the healthy foods."
A Surprising Effect
But since the healthful items now cost a lot less, the moms had money leftover. Esptein says they used it to buy more junk food.
"When you put it all together, their shopping baskets didn't have improved nutrition," says Epstein — they had the same amounts of fats and carbohydrates.
If subsidizing healthful foods leads to the unintended consequence of people spending more on junk, might there be another way to structure incentives?
The researchers tried a different price manipulation: They basically placed a hefty tax on high-calorie, low-nutrient foods. They found that that moms stopped buying so much junk.
The researchers say their findings suggest that the taxes were more effective than subsidies. This conclusion doesn't surprise Karlan. He sites the theory of loss aversion: "People are just more responsive to price increases than decreases."
Karlan says a "sin tax" — charging more for unhealthful foods — would not change families' diets or approach to nutrition overnight. But it could serve as a first step in raising awareness of bad habits, alerting us to the kinds of things we choose to snack on.
Effecting Change In The Real World
All kids love a treat. And the students at the Argenziano School in Somerville, Mass., are no exception.
Some of their favorites? "Skittles" calls out one seventh-grader. "Doritos," says student Marcos Azerbido. "I used to bring Doritos every day."
But not anymore. These days, fresh fruit is the only choice for their mid-morning snack. On their way out the door for recess the kids reach into bins filled with apples and bananas and other fruits depending on the season. The fruit is funded through a USDA grant, and free to the students.
"Once they get it every day, they'll eat like three bananas," says teacher Sharyn Lamer, who has tried for years to enforce a healthful snack rule in her classroom. She says when parents were sending their kids to school with chips or sugary treats it was tough.
"But now it's the rule in the entire school. And the kids are into it," says Lamer. "It's not me being the mean teacher who's not letting them have their Doritos!"
As habits change it school, Lamer says the students may think differently about their choices at home.
LINDA WERTHEIMER, host:
This is MORNING EDITION from NPR News. I'm Linda Wertheimer, in for Steve Inskeep.
RENEE MONTAGNE, host:
And I'm Renee Montagne.
Today in Your Health, we have news that comes from research about kids and families. In a moment, a story about how earaches can shape how the brain learns to hear. First, NPR's Allison Aubrey reports on how to get kids and families to eat better.
ALLISON AUBREY: The first incentive is financial. Let's call it bucks for broccoli, or cash for carrots. Can you make people buy healthier food? Would that work? I put the question to Dean Karlan, a behavioral economist at Yale University.
Professor DEAN KARLAN (Behavioral Economist, Yale University): So in the case of broccoli, you want to find out who's not eating broccoli, and then pay them to eat broccoli.
AUBREY: But Karlan says financial incentives for food purchases could be tricky. For instance, how much cash is needed to get people's attention? Researchers at the University of Buffalo have just finished a study looking into this. They recruited a bunch of moms to shop for groceries in a simulated supermarket, and gave them each the same amount of money. The researchers manipulated the prices a couple of different ways. First, they made the healthy foods - items such fruits and vegetables - a lot cheaper.
Dr. LEN EPSTEIN (Pediatrics, University of Buffalo): And then we looked at the purchasing patterns of these mothers, as if they were purchasing these foods for their family for the week.
AUBREY: Researcher Len Epstein says the moms' choices were somewhat predictable.
Dr. EPSTEIN: They did buy more of the healthier foods.
AUBREY: But here's the rub: Since the healthy foods cost a lot less, the moms had money left over. And what did they do with it? Well, Epstein says they used it to buy more junk food.
Dr. EPSTEIN: So when you put it all together, their shopping baskets didn't have improved nutrition. They had basically the exact, same percentage of fat and percentage of carbohydrates.
AUBREY: So if subsidizing healthy foods leads to the unintended consequence of people spending more on junk, might there be another way to structure incentives?
Well, when the researchers tried a different price manipulation - basically, placing a hefty tax on junk food - they found that this stopped people from buying so much of it. So are taxes more effective than subsidies?
Dr. EPSTEIN: That's what our data looks like.
AUBREY: And behavioral economist Dean Karlan says the findings are not a big surprise.
Prof. KARLAN: No, not at all. People are more responsive to price increases than decreases.
AUBREY: Karlan says a junk food tax would not change families' diets overnight. But it could serve as a first step to raise awareness of bad habits, such as the kinds of things we choose to snack on. For example, kids like sweets.
Unidentified Child #1: Skittles.
Unidentified Child #2: Skittles.
Unidentified Child #3: Yeah, Skittles.
Unidentified Child #4: Skittles.
AUBREY: But research shows that limiting kids' choices can really make a difference. These middle-schoolers in Somerville, Massachusetts, are not allowed to bring Skittles to school. In fact, they can't bring snacks at all.
Mr. MARCOS AZERBIDO (Student, Argenziano School): I used to bring Doritos every day. But then they gave us juicy fruit.
AUBREY: Fresh fruit is the only option Marcos Azerbido, and all of his classmates, have for snacks these days.
Unidentified Child #5: Bring an apple.
Unidentified Child #6: There are green ones and red ones and yellowish ones and, like, orangey ones.
AUBREY: On their way out the door for morning recess, the kids reach into bins filled with apples and bananas.
Ms. SHARYN LAMER (Teacher, Argenziano School) Once they get it every single day, once it's right in front of their face, yeah, they'll have like, three bananas. They'll eat a ton.
AUBREY: Seventh grade teacher Sharyn Lamer says she couldn't convince many kids to eat fruit at snack time when parents were sending them chips or sugary treats.
Ms. LAMER: But now that it's the rule all the way across, the kids are really into it. And then it's not me being the mean, bad teacher that's making them not eat their Doritos.
AUBREY: Lamer says as the whole school culture has changed, kids may start thinking a little differently about food choices at home.
Allison Aubrey, NPR News. Transcript provided by NPR, Copyright NPR.