The study sample of 171 teens aged 13-16 viewed unhealthy fast food commercials with cheeseburgers and French fries; healthier commercials with salads, grilled chicken sandwiches; and nonfood commercials in a functional magnetic resonance imaging (FMRI). The participants were able to consume food featured in the commercials that varied in nutrition in a simulated fast food restaurant.
The study found that teens who had greater responses in reward centers of the brain when viewing commercials for unhealthy foods like cheeseburgers and milkshakes from fast food restaurants ate more junk food in a simulated fast food restaurant.
Surprisingly, teens who had heightened brain responses associated with reward, memory and visual attention to commercials for healthier foods like salads and smoothies from fast food restaurants were also prone to eat more junk food.
The study also found that more neural activation in the brain's "reward" region predicted greater total food intake; healthier commercials from fast food restaurants are unlikely to encourage healthy food consumption; and the restaurant logos and branding trigger cues associated with the sale of predominantly unhealthy foods.
Teens who showed less activation in a brain region associated with visual attention to unhealthy fast food commercials had more healthier food intake, the study showed.
"The ability of fast food commercials to prime these brain systems, potentially outside of the conscious awareness, may make it particularly challenging for adolescents to defend themselves against the negative effects of food marketing," said Ashley Gearhardt, UM associate professor of psychology and the study's lead author.
Reducing the overall amount of food advertising viewed by teens is an important target for improving health, Gearhardt suggested.
The findings have been published in the American Journal of Clinical Nutrition.
Xinhua
