You might not care about the fast-food commercial shots of juicy burgers or creamy milkshakes, but they might change your beliefs about these items, whereas shots of fresh salads and berries might not, according to a new study.

University of Michigan researchers found that in adults who did not already hold strong beliefs about how foods affect their emotions, fast-food TV ads for cheeseburgers, chicken nuggets and milkshakes increased their beliefs that they would feel positive emotions while eating those types of food.

However, there was no evidence that ads for salads and yogurt parfaits changed beliefs about feeling positive emotions while eating fruits and vegetables.

This research is one of the first studies to test the effects of food advertisements on food-related emotional expectations. The study, which involved 718 participants, tested how food ads affect food-related emotional expectations in adults and whether effects differed by individual levels of “food addiction” symptoms.

Food addiction is marked by strong cravings for highly processed foods, diminished control over their intake, overconsumption despite negative consequences including clinically significant distress and diet-related disease, and stronger food-related emotional expectations, previous research has shown.

Participants were randomly assigned to watch 15-second video advertisements for highly processed foods, minimally processed foods, both food groups, or cell phones (control). They completed questionnaires about their beliefs, feelings and behaviors.

For participants with fewer symptoms of food addiction, watching video ads for highly processed foods increased expectations that one would feel positive emotions while eating those foods, the study showed.

“Many people think that eating highly processed foods like cheeseburgers and French fries will make them happier, and these beliefs are especially strong in people struggling to control their intake of highly processed foods,” said Jenna Cummings, lead author and former U-M research fellow. “Regulating fast-food advertisements and changing beliefs about how highly processed foods affect emotions could help people eat more nutritious foods.”

Participants viewed the video for a short duration. Cummings, who is a psychology lecturer at the University of Liverpool, said it will be important for future research to examine how longer exposures to food ads change beliefs about the emotional effects of food, how long any changes in beliefs endure, and how quickly any changes in beliefs affect someone’s typical eating behavior.

The research, which appears in the Journal of Health Psychology, was written by U-M psychology graduate student Lindzey Hoover and Ashley Gearhardt, U-M associate professor of psychology.