Knowing that fast food is not especially healthy may not be enough to weaken its appeal.
In two studies involving adults in Australia and the United States, people who said they liked familiar fast food and sugary drink brands more also reported eating foods high in fat and sugar more often. The relationship remained even after researchers considered how healthy participants thought the brands were.
The findings, published in the Journal of Health Communication, do not show that liking a brand causes someone to eat a poorer diet. The studies were based on surveys taken at one point in time, so it is also possible that people who already eat more fast food develop stronger attachments to the brands they encounter frequently.
Still, the results offer an interesting look at the gap between what people know about food and how they feel about it.
The researchers conducted two separate studies. The first included 114 Australian university students. The second, which was preregistered before the analysis began, recruited 190 U.S. adults online. After excluding people who failed attention checks, the American sample included 145 participants ranging in age from 18 to 77.
Participants saw logos from familiar fast-food and beverage companies and rated how much they liked the brands, how familiar they were with them and how beneficial they thought the brands were for health.
The U.S. group saw brands including McDonald’s, Burger King, Wendy’s, KFC, Domino’s, Subway, Starbucks, Dunkin’, Coca-Cola, Pepsi and Red Bull.
Participants also completed a questionnaire about how often they ate foods high in fat, sugar or both over the previous year.
Across both studies, stronger brand liking was associated with more frequent consumption of those foods. That association remained after researchers accounted for factors including age, gender and, in the U.S. study, education.
People who scored higher on a separate measure of reward-driven eating, which includes food cravings, eating for pleasure and feeling less control around food, also reported eating high-fat and high-sugar foods more often.
Those two factors appeared to matter independently. In other words, liking fast-food brands was associated with eating patterns even after the researchers considered a person’s tendency toward reward-driven eating.
One result surprised the researchers.
They expected people who liked a fast-food brand but recognized it as unhealthy to report eating less of those foods. That was not what they found.
How healthy participants thought the brands were did not weaken the relationship between brand liking and reported diet. And in both studies, people who liked the brands more also tended to rate them as healthier.
That does not necessarily mean people believe burgers, fries or soda are good for them.
The question asked participants to rate the health benefits of the brand as a whole, and the researchers acknowledge that brands sell a wide variety of foods. Someone’s opinion of a brand also does not tell researchers which specific menu items that person actually buys.
The findings instead raise the possibility that positive feelings about familiar brands may shape how people judge them.
Marketing is designed partly to create exactly those kinds of positive associations. Repeated exposure can make a brand feel familiar, enjoyable and trustworthy, whether it appears in an advertisement, social media post, sporting event or restaurant sign.
But this study cannot tell whether marketing created the brand attachment seen in the participants.
It also cannot determine which direction the relationship runs. People may eat more fast food because they like the brands, or they may like the brands because they eat there more often. Both could also be happening at the same time.
Other influences were not fully captured either. The researchers did not collect detailed information about household income, and they note that price, convenience and access can all influence how often people eat fast food.
The dietary measure was another limitation. Participants reported how frequently they ate certain foods, rather than the actual amounts they consumed. The researchers also did not collect detailed food records that would allow them to evaluate the nutritional quality of everything a participant ate.
That is why the findings are better understood as a link between brand attitudes and reported high fat and high sugar eating, rather than proof that liking fast food brands predicts every aspect of someone’s diet.
The study also found no consistent connection between brand liking and body mass index. In the U.S. sample, reward-driven eating was associated with higher BMI, but attitudes toward fast-food brands were not.
The broader finding is less about whether people understand nutrition and more about how food choices are shaped by competing influences.
Someone can know that a food is not particularly nutritious and still enjoy it, crave it or feel strongly attached to the brand selling it. This study suggests those positive feelings may be worth paying attention to when researchers try to understand why nutrition knowledge does not always translate neatly into eating behavior.
The research was supported by a University of Technology Sydney Graduate School of Health Seed Funding Grant and grants from the Australian Research Council.