A customer shops for fresh produce at Whole Foods in Ann Arbor, Mich. (Rebecca Cook/Reuters)

Forget the nutrition facts label, the ingredients list and the say-so of experts: A new study finds that shoppers think a food is healthy only when it costs them more.

The study, forthcoming in the Journal of Consumer Research, is the latest evidence that your brain may work against you when it comes to choosing healthy foods. Researchers say our subconscious association of cost with health — what they call the “healthy = expensive intuition” — can prompt shoppers to not only spend more money but also to make uninformed health decisions without realizing it.

“We often ask how consumers process information about what they should eat,” said Kelly Haws, a processor of marketing at Vanderbilt University and a co-author of the new paper. “The truth is, we give them a ton of information — and they don’t process it all.”

Haws and other researchers in the realm of behavioral economics have a name for this phenomenon: It’s called heuristics, and it basically describes any sort of mental shortcut that we use to simplify decisions. Instead of consciously evaluating all of the information we have about a product — its calorie count, its ingredients, its brand, its location in the store — our brains rely on simple assumptions, such as the belief that healthy foods always cost more.

These assumptions can be deeply flawed, particularly when they’re applied to an overbroad set of situations. And we do apply them broadly when it comes to food: A 2013 study published in the journal Appetite concluded that heuristics, not rational choice, are the basis for most of our food decisions.

Given that prevalence, Haws said, a heuristic like “healthy = expensive” can have profound implications for consumer choice and, by extension, public health — particularly since the “healthy = expensive” intuition appears to be so persuasive to the consumers who depend on it.

To test the power of the heuristic, Haws and her two co-authors — Rebecca Reczek at Ohio State, and Kevin Sample at the University of Georgia — ran five experiments on several hundred college undergrads. In the first two experiments, participants were shown a “new” food product and asked to guess either its price or health value. In both iterations of the experiment, participants assigned higher prices to healthier products, and better health grades to more expensive foods.

In the third, participants were asked to order the more healthy of two sandwiches; they consistently picked the more expensive one, even when the researchers switched the prices. In the fourth, subjects rated an unfamiliar vitamin, DHA, as more important to a healthy diet when it was advertised as part of an expensive trail mix, rather than an average-priced one. “Consumers over-apply their belief that healthy = expensive … suggesting that the intuition can bias perceptions of what ingredients are ‘healthy,’ ” the authors write of that experiment’s conclusions.

In the final trial, participants were asked to evaluate reviews of a new, super-healthy protein bar, which cost either 99 cents or $4. They spent far more time reading the reviews of the 99 cents bar — a sign, the researchers suggest, that most couldn’t believe a “healthy” item would cost so little.

“Our results suggest that consumers have this really overwhelming sense that healthy equals expensive,” Haws said. “And that has a big impact on their food decisions.”

The United States government once considered butter and margarine as one of seven food groups to consume daily. Look back at other advice that, sadly, is no longer a part of the USDA's dietary guidelines. (Jayne W. Orenstein/The Washington Post)

Specifically, health-conscious shoppers are potentially overspending, and on products that aren’t necessarily all that good for them. Budget-minded shoppers may ignore their grocery store’s plethora of cheap, healthy options. And all consumers are at risk of forming opinions about promotional health and nutrition claims — such as the importance of DHA — based on nothing but the price of the item.

That’s not all, Haws said. The healthy = expensive intuition is just one of “a universe of mental shortcuts” that we rely on to choose food, and many of those shortcuts also appear to be flawed. Previous research has described a “supersize bias,” for instance, in which consumers ignore calorie counts and other health information when presented with a meal that seems like a good value. The majority of Americans also embrace what’s called the “unhealthy = tasty intuition” -- the belief that food must be unhealthy to taste good.

Even the shape of a food’s package plays a role: Researchers in the Netherlands recently found that consumers think foods in thin packages are healthier.

“Are they reading the labels, processing the information? Probably not,” said Deborah Cohen, a senior natural scientist at the Rand Corp. and the author of “A Big Fat Crisis: The Hidden Influences Behind the Obesity Epidemic — and How We Can End It.” “The problem with shopping is that it requires lots of decisions, and consumers have limited processing capacity. Every person has a limit on how many good decisions they can make before they start taking mental shortcuts” -- such as assuming that pricey food is healthy.

Unfortunately for health-minded consumers, rewiring these sorts of heuristics is difficult; they are, after all, a normal part of our psychology. That is why advocates such as Cohen have advocated for more oversight of in-store food marketing, which Cohen said exploits consumers’ mental exhaustion.

Some behavioral economists — such as Antoinette Schoar of MIT and Saugato Datta of ideas42 — have advocated for public health programs that rely on heuristics, themselves. Traditional interventions typically involve in-depth nutrition education: The Agriculture Department’s suggested nutrition lesson plans for high school students comprise 84 pages.

“Everywhere, policy seeks to improve complex decisions by providing people with commensurately complex information,” Schoar and Datta wrote in 2014. “Rather than inundate them with a mass of complex information, we argue that such policy interventions should concentrate on developing, testing and disseminating simple but effective rules of thumb, or ‘heuristics.’ ”

One common technique, when it comes to diet, involves creating (and sticking to) simple nutritional edicts: “eat a salad with every dinner,” for instance, or “never eat chocolate.”

Haws has a heuristic of her own: “Expensive does not equal healthy.” For consumers, she said, the easiest solution to the healthy = expensive intuition is to simply remind themselves that it isn’t true while they’re shopping or dining. Haws and Cohen both suggest arriving at the grocery store with a prepared shopping list, the better to defend yourself against your own mental shortcuts. Haws also cycles through a mental list of cheap and healthy foods while she’s moving through the grocery store.

“You’ve probably heard of mindless eating. This is the same idea,” Haws said. “All you need is awareness: Just stop, take a second, and think about it.”

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