Obesity-gene may prompt kids to respond more to fast food ads

The overt response of your kids to advertisements of burgers, pizzas and french-fries may be the result of a key obesity gene influencing their brain to respond more to food advertisements and other cues to eat, a study has found.

The study showed that children with the fat-mass and obesity-associated (FTO) gene -- which strongly predicts obesity across the lifespan -- had greater activity in brain reward centres when watching fast food commercials.

The nucleus accumbens, a region in the brain commonly associated with reward craving, was not only physically larger in children with the obesity-risk FTO genotype compared to genetically low-risk children but also showed a stronger craving response to the 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 over-eating unhealthy foods," said lead author Kristina M. Rapuano, a graduate student at Dartmouth College in New Hampshire, US.

Previous studies have showed 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.

For the study, the team examined 78 children, aged nine to 12 years old, who watched a children's television show in an MRI scanner, which included 12 minutes of commercial breaks -- half were advertisements for fast food and the other half for non-food items. 

The brain scans suggest that these children may be especially vulnerable to food cues and that limiting food advertisement exposure could be an effective way to combat child obesity.

"About one-third of commercials children see on network television are food advertisements, and each one is a prompt to eat," added Diane Gilbert-Diamond, Assistant Professor at Dartmouth College.

The findings are published in the Proceedings of the National Academy of Sciences (PNAS).