News Release

Naturally healthy: How much do adolescents know about food?

Adolescents—like nutrition experts—use “naturalness” to judge a food’s healthiness

Peer-Reviewed Publication

Max Planck Institute for Human Development

How natural a food product is plays a key role in how healthy it is perceived to be—not only by nutrition experts, but also by adolescents and young adults. At the same time, there is considerable variability in adolescents’ ratings of food products. These are the results of a new study conducted by researchers at the Max Planck Institute for Human Development and Aarhus University, published in the Journal of Experimental Psychology: Applied.

Any trip to the supermarket involves countless decisions. There are over 10,000 products on the shelves of an average German store, and even within a single product category the choice is staggering: Consumers often have the choice of some 400 meat products and 200 bakery items. Finding your way around this complex everyday environment calls for good intuitive decision making. Previous research has shown that children’s perceptions of the quality and healthiness of individual food projects are still hazy. But what about adolescents, who may already be responsible for buying groceries and who often spend their pocket money on things to eat?

The researchers compared the food perceptions of 36 adolescents aged between 13 and 16 years with those of 68 food experts (e.g., dietitians and nutrition students). A third group consisted of young adults with an average age of 30 years. All participants were shown pictures of 43 common food products and asked to rate each product on 17 characteristics, including their fat, sugar, and protein content, level of processing, origin, and packaging. In addition, participants were asked to indicate how “healthy” they thought each product was.

Based on the participants’ patterns of responses, the researchers identified dimensions along which participants structured their perceptions of foods. They found that the adolescents’ and experts’ assessments had much in common. “In all groups, a key factor guiding perceptions was how natural a food was. Foods that have less packaging, contain fewer additives, and are less processed were perceived as similar and grouped together,” says Thorsten Pachur, Senior Research Scientist in the Center for Adaptive Rationality at the Max Planck Institute for Human Development, and principal investigator in the study. “Naturalness was also crucial to how healthy the food was judged to be. The higher the score on the naturalness dimension, the healthier a food was rated as being.” This simple rule for judging the healthiness of foods was applied by the adolescents and young adults—and even the nutrition experts seemed to follow it. Overall, healthiness ratings were similar across the three groups. Apples, water, bananas, and milk were perceived as very healthy, sun-dried tomatoes and muesli bars as fairly healthy, and chocolate bars and cookies as least healthy.

But there were also some interesting differences between the three groups. The adolescents rated some foods—such as orange juice and fish sticks—as being significantly healthier than the experts did. It seems likely that their judgments were informed by the perception that oranges and fish are healthy. But orange juice has a high sugar content, and the breading on fish sticks is high in fat and calories, canceling out the benefits of fish being high in minerals and omega-3 fatty acids. Only the experts seemed to be aware of this. What’s more, the adolescents’ mental classifications of foods seemed to involve a “sweet versus salty” distinction—that is, a simple taste component. In the other groups, perceptions were structured solely by ingredients—primarily, cholesterol, fat, and protein. The adolescents also used the taste component to assess foods’ healthiness, rating sweet foods as less healthy than salty foods.

Another difference between the groups was in the variability of their answers. Whereas the expert ratings were largely consistent, the adolescents’ ratings were much more varied. This indicates that some adolescents lacked the relevant food knowledge and guessed at some of the answers. For example, individual assessments of salmon and ketchup or, more generally, nutrients such as “good” fats, fiber, and cholesterol varied markedly.

The results show that aspects of naturalness help consumers to navigate the complex food environment and intuitively assess how healthy a food is. Adolescents already have this intuition—and, as it is also used by experts, naturalness indeed seems to provide effective clues for identifying healthy foods. At the same time, the study suggests that nutrition education for adolescents needs to target their knowledge about food ingredients. This would be beneficial, as findings from other studies show that better knowledge about food and nutrition is linked to healthier consumer choices. Overall, however, a foundation for good intuitive food decisions seems to be laid.

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