Kids With ‘Obesity Gene’ Are More Tempted by Junk Food Ads

A genetic trait related to obesity may make some children more susceptible to junk food commercials on TV, a new study published in the journal Proceedings of the National Academy of Sciences suggests.

Using brain scans, researchers at Dartmouth College discovered that children who were genetically at risk for obesity had greater activity in the brain reward centers while watching fast food commercials.

“By examining the still-developing brain and its reward-related structures, our findings help explain why children who are genetically at-risk for obesity may be prone to overeating unhealthy foods,” said first author, Kristina M. Rapuano, a graduate student in the Brain Imaging Lab in the department of Psychological and Brain Sciences at Dartmouth College.

Unlike previous studies that used only still images, the new study used television fast food advertisements to understand the brain’s response to food cues in the real-world. The researchers asked 78 children between the ages of nine and 12, to watch a children’s TV show while in an MRI scanner. Like at home, the TV show included 12 minutes of commercial breaks — half the advertisements were for fast food and the others were for non-edible items. The children were also checked for their risk for obesity based on the fat-mass and obesity-associated (FTO) gene.

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They found that in kids who were genetically predisposed to obesity, the region of the brain associated with reward craving became larger and had a stronger craving response to food commercials, compared to the children who were not at risk for obesity.

“About one-third of commercials children see on network television are food advertisements, and each one is a prompt to eat,” said senior author, Diane Gilbert-Diamond, assistant professor of Epidemiology at Dartmouth’s Geisel School of Medicine and member of the Norris Cotton Cancer Center. “We know from our prior work that children with this same genetic obesity risk factor are more likely to overeat after watching food advertisements on TV, even when they are not hungry. The brain scans suggest that these children may be especially vulnerable to food cues, and that limiting food advertising exposure could be an effective way to combat child obesity.”

Ruth Loos, director of genetics of obesity and related metabolic traits program at the Charles R. Bronfman Institute of Personalized Medicine in Mount Sinai in New York City, believes this study proves that weight gain isn’t just a matter of willpower.

“Genetic studies have shown that willpower might be controlled by people’s genetic make-up,” said Loos, who was not involved with the study. “The current study shows that, potentially, the reason why people with this genetic trait gain weight is because it is hard for them to resist food when they see it, compared to people who do not have the variant.”

Despite various government initiatives, childhood obesity remains a big problem in the United States. In 2014 alone, about 12.7 million children and adolescents were considered obese, according to the Centers for Disease Control and Prevention.