Familiarity with television fast-food ads linked to obesity

"We know that children and adolescents are highly exposed to fast-food restaurant advertising, particularly on television. This study links obesity in young people to familiarity with this advertising, suggesting that youth who are aware of and receptive to televised fast-food marketing may be at risk for health consequences," said lead author Auden C. McClure, MD, MPH, FAAP, assistant professor in the Department of Pediatrics at Children's Hospital at Dartmouth, Dartmouth-Hitchcock Medical Center.

Previous research has shown that watching TV is associated with obesity. Dr. McClure and her colleagues sought to determine whether recognition of fast-food ads on TV is associated with obesity in adolescents and young adults.

The researchers surveyed a national sample of 3,342 youths ages 15 to 23 years. Participants were asked about their height, weight, age, gender, race, socioeconomic status, exercise, consumption of soda or sweet drinks, frequency of eating at quick-service restaurants, how many hours they watched TV each day, and whether they snacked while watching TV.

They also were shown 20 still images selected from television ads for top quick-service restaurants that aired in the year before the survey. The images were digitally edited to remove the brands. Individuals were asked if they remembered seeing the ad, if they liked the ad and if they could name the restaurant brand. In addition, they were shown 20 ads for alcohol.

Results showed that about 18 percent of participants surveyed were overweight, and 15 percent were obese. The percentage of youths who were obese was significantly higher among those who recognized more ads than those who recognized few ads (17 percent vs. 8.3 percent). Even after controlling for the variables listed above, youths who recognized many ads were more than twice as likely to be obese compared with those who recognized few ads.

"A similar association with obesity was not found for familiarity with televised alcohol ads, suggesting that the relationship was specific to fast-food advertising content," Dr. McClure said. "After accounting for overall TV time, TV ad familiarity was still linked with obesity suggesting that this finding is not simply due to increased sedentary time or an effect of TV programming."

However, eating more frequently at fast-food restaurants depicted in the ads was not associated with obesity.

"The relation between fast-food marketing and obesity is not simply that it prompts more quick-serve restaurant visits," said study co-author James D. Sargent, MD, FAAP, professor in the Department of Pediatrics at Children's Hospital at Dartmouth. Instead, "individuals who are more familiar with these ads may have food consumption patterns that include many types of high-calorie food brands, or they may be especially sensitive to visual cues to eat while watching TV. More research is necessary to determine how fast-food ad familiarity is linked to obesity," he added.

"Given the broad exposure of youth to advertising, the more we know about how media and marketing affect young people, the better equipped we are as pediatricians and parents to guide them in making healthy diet choices," Dr. McClure concluded.