(CNN) Determining what exactly is a "healthy" food has us all scratching our heads.
A new survey suggests that most Americans are confused about what counts as a healthy food choice.
About eight in 10 survey respondents said they have found conflicting information about what foods to eat and what foods to avoid -- and more than half of them said the conflicting information has them second-guessing the choices they make, according to the International Food Information Council Foundation's annual Food and Health survey, which was released Tuesday.
"I wasn't that surprised to see that 78% reported that they encountered conflicting information, but our follow-up question to that had, I think, a really interesting data point in it, and that was that about half -- so around 56% -- say that this conflicting information causes them to doubt the choices that they're making," said Liz Sanders, director of research and partnerships at the foundation and a co-author of the survey.
"I think that shows that for at least half of our respondents, this conflicting information was leading to some doubt that made it harder to sort through all the conflicting information," she said. "Americans rely on many different sources for their information when it comes to what foods to eat and what foods to avoid. Not all of these sources are really highly trusted, and it is likely that these sources share inconsistent information."
The survey involved 1,002 American adults, who completed it online in March. Nearly 60% of respondents ranked being "high in healthy components or nutrients" as one of the top three factors for a "healthy" food.
Slightly more than half of respondents ranked "free from artificial ingredients, preservatives or additives" among the top three factors, and nearly 50% ranked "part of an important food group that I need to build a healthy eating style" among the top three factors.
Factors such as "organic" and "non-GMO," or genetically modified, were less likely to be ranked.
The researchers found that there appeared to be much confusion about what eating habits are healthy and what aren't. Many respondents said they turn to their friends and family for guidance on food choices, even though they see dietitians and health care professionals as the most trusted sources for guidance.
"Trusted nutrition information is hard to find, and the public is inundated with conflicting messages, including from dubious sources," said Dr. Dariush Mozaffarian, dean of the Friedman School of Nutrition Science and Policy at Tufts University, who was not involved in the new survey.
"Looking at the survey results, it's positive that the public recognizes the importance of foods being high in healthy components, nutrients, and part of an important food group and correctly pay less attention to criteria like GMO or organic," he said.
When considering the healthfulness of individual specific components and ingredients, most survey respondents placed vitamin D, fiber and whole grains at the top of the list and saturated fats at the bottom.
When it comes to unsaturated fats, an age gap emerged in who found those fats to be "healthy." About 50% of survey respondents 65 and older called unsaturated fats healthy, whereas just 33% of those 18 to 34 did.
"The low recognition of the importance of healthy fats is disappointing," Mozaffarian said.
Older respondents were also more likely to label saturated fats as unhealthy, which most experts agree is correct, according to the survey.
The spread of conflicting information and even misinformation might be playing a role in America's obesity epidemic, said Dr. Roxanne Sukol, preventive medicine specialist at the Wellness Institute at Cleveland Clinic, who was not involved in the new survey. She did not find the survey results to be surprising.
"Two-thirds of us are overweight or obese," Sukol said.
"Fifty percent of Americans have either diabetes or prediabetes by age 65 now," she said, referencing data from the US Centers for Disease Control and Prevention (PDF). "That means that whatever we're doing, it's really not working. So it's proof that yes, in fact, people are confused. They're not making choices that benefit their health, and it's not because they're not trying."
As with any survey, there are limitations, and all of the data in this survey came from self-reports, Sanders said.
"We're limited because we can't really examine how people are behaving; we just know how they say they're behaving. So that is one limitation with any self-reported survey," she said. However, Sanders added that since this survey is conducted annually, the data allow trends to emerge.
"Our biggest trend over time has to do with purchasing factors, and we know that taste and price have always been the top two factors that have driven purchasing, with healthfulness following behind in the third spot," Sanders said. "In terms of what is healthy, we know that it doesn't always beat out what tastes the best or what has the best price, in terms of impacting a food purchase."
" 'Healthy' is a term that's at the core of so many of our conversations around food, but there's still a lot of debate about what is healthy, and we see this around the FDA's recent efforts to update guidelines for the term 'healthy' and its use in food labeling," Sanders said.
Last year, the US Food and Drug Administration launched a public process to redefine what the word "healthy" means when it's used on food labels.
For a food product to be marketed as healthy, it should have low levels of total and saturated fat, sodium and cholesterol, and have at least 10% of the daily requirements for vitamins, fiber and other nutrients, according to the FDA's current criteria (PDF).
The Cleveland Clinic's Sukol thinks the word "healthy" is confusing and should be replaced with the term "nourishing," as some processed foods have been marketed as "healthy."
"The big problem is that we've been told that we can nourish ourselves with these ultraprocessed foods, and we cannot. They don't nourish us. That's why I believe that obesity is (at least in part) a malnourished state, as opposed to the standard message being propagated in our society, which is that obesity is an overindulged state," Sukol said. "But if that were true, then diets would work."
While we can't seem to find a way to define what is "healthy," our brains innately respond to what is "nourishing," Sukol said. For instance, if you eat a big bag of candy at the movies and then go to dinner, you probably would still have an appetite for a meal.
"But if they sold roasted Brussels sprouts and grilled salmon at the movie theater, you wouldn't go out for dinner afterwards, because you would be satisfied. Your brain knows the difference," Sukol said. "If there's a conflict between what we think we know and what our brain is telling us. We don't trust our brain. We trust what we think we learned. So I'm not surprised at all that everyone is confused."
Sukol points to the way in which food products have been marketed as being associated with some of the confusion and conflicting messaging around what is "healthy."
"It's everything else around the food, too. Another great example is the way shopping carts are constructed. So, if shopping carts were designed to support our spending more time in the fresh produce section than anywhere else ... then they would have shelves in the front, and you would access each shelf individually and fill it with produce and then go to the next shelf," Sukol said.
"But it's not that way. Everyone uses the baby section for produce, and then when that's full, then we use the rest of the shopping cart to put boxes and cans and bottles in. In other words, all the processed stuff, with some exceptions," she said. "The shape itself is designed to carry boxes."
To get reliable information on which foods contribute to an overall healthy diet, Sanders recommended consulting the federal Dietary Guidelines for Americans, which are published every five years. The latest guidelines were published last year.
"That's kind of the gold standard in terms of consolidating everything we know from peer-reviewed research and getting expert opinion," she said.