With 2017 just around the corner, many of us will soon be trawling grocery stores in the search for healthful foods to kick-start the New Year's resolution of losing weight. But according to new research, you should avoid looking at the prices - it might skew your perception of what foods are good for you.
Study co-author Rebecca Reczek, from the Fisher College of Business at Ohio State University, and colleagues found that people often perceive healthful foods to be more expensive, despite there being no evidence to support this view.
The team found that consumers make food choices based on this belief, and the price of foods may also influence how important we perceive certain health conditions to be.
Reczek and colleagues came to their findings - published in the Journal of Consumer Research - by conducting five experiments on different groups of participants.
The aim of the study was to get a better understanding of "lay theories" in relation to the cost of healthful foods. In simple terms, lay theories are ideologies that people use to make sense of their social environment.
One common lay theory is that healthful foods are more expensive than less healthful foods. The researchers point to one example of this popular theory - the nickname given to the health foods store Whole Foods, which is "Whole Paycheck."
While there are certain types of health foods that are more expensive - such as organic and gluten-free products - Reczek notes that it does not always cost more to eat healthily.
Costly food products perceived as more healthful in experiments
For their study, the researchers tested people's perceptions of the price of healthful foods in a series of experiments.
In one experiment, the team provided participants with information on a "new" food product called granola bites. Some subjects were told the product was a health grade A- (a healthful food), while the remaining participants were told the product was a health grade C (less healthful).
When each participant was asked how much they thought the granola bites cost, subjects who were told they were a health grade A- thought the bites were more expensive than subjects who were told they were a health grade C.
This finding offers support to the popular belief that healthful foods are costlier. This relationship was further confirmed in another experiment, in which participants rated a breakfast cracker as more healthful when told that it was more expensive than a cheaper, identical cracker.
For the next experiment, the team set out to investigate whether this lay theory influences people's behavior when it comes to choosing foods.
Participants were asked to imagine that a work colleague had asked them to order his or her lunch. Half of the subjects were told that their co-worker had requested a healthful lunch, while the remaining subjects had no instruction.
Next, participants were offered two choices of food product on a computer screen: a chicken balsamic wrap and a roasted chicken wrap. Ingredients were listed for both products.
The price was also shown for each product. However, the chicken balsamic wrap was listed as more expensive for some subjects, but for others, the roasted chicken wrap was costlier.
The researchers found that participants who were instructed to choose a healthful product were significantly more likely to opt for the more expensive wrap, regardless of which wrap it was. This suggests that our food choices may be influenced by the lay belief that healthful products cost more.
"People don't just believe that healthy means more expensive - they're making choices based on that belief," notes Reczek.
Testing how price cues influence health perceptions
In the final two experiments, the team sought to gain a better understanding of how food prices influence peoples' perceptions of what is good for us.
Firstly, the researchers asked participants to imagine that they were in a grocery store to purchase trail mix and told to choose from four differently priced products.
One of the mixes was called the "Perfect Vision Mix." For some subjects, this mix was promoted as being "rich in vitamin A for eye health," while for others, the product was hailed as "rich in DHA (docosahexaenoic acid) for eye health."
The team notes that both vitamin A and DHA are believed to be beneficial for eye health, but DHA is less familiar.
For some participants, the Perfect Vision Mix was shown at an average price, while for others, it was more costly than the other three mixes.
When asked about their perceptions of the "key" ingredient in the Perfect Vision Mix, participants thought that vitamin A was equally important for a healthful diet, regardless of how much the mix cost.
However, when DHA was promoted as the key ingredient, subjects were more likely to think that it was an important part of a healthful diet when it was shown as more expensive, compared with when it was an average price.
"People are familiar with vitamin A, so they feel they can judge its value without any price cues," explains Reczek. "But people don't know much about DHA, so they go back to the lay theory that expensive must be healthier."
The team was further surprised during the experiment in which the subjects were told that DHA helped to prevent macular degeneration. When the DHA-containing mix was more expensive, participants were more likely to rate macular degeneration as a popular health issue, compared with when the product was an average price.
Findings are 'concerning'
In the last experiment, participants were presented with a new product called the "Healthiest Protein Bar on the Planet."
Some subjects were told that the bar would be priced at $0.99, while the remaining participants were told it would cost $4. All participants were given the opportunity to read reviews before giving their own opinions on the product.
When subjects were told that the bar would be priced at $0.99, the researchers found that they were much more likely to read reviews, compared with when they were told that the bar would cost $4.
"People just couldn't believe that the 'healthiest protein bar on the planet' would cost less than the average bar," says Reczek. "They had to read more to convince themselves this was true. They were much more willing to accept that the healthy bar would cost twice as much as average."
All in all, Reczek and team believe that their results are a worry for consumers.
"It's concerning. The findings suggest that price of food alone can impact our perceptions of what is healthy and even what health issues we should be concerned about."
However, the researchers suggest that by being aware of the common misconception that healthful foods are always more expensive and by using "objective evidence" to assess food products, we can overcome this lay theory.
"It makes it easier for us when we're shopping to use this lay theory, and just assume we're getting something healthier when we pay more. But we don't have to be led astray," says Reczek. "We can compare nutrition labels and we can do research before we go to the grocery store. We can use facts rather than our intuition."