fMRI shows kids’ brains lighting up for unhealthy foods pushed on TV

Neuroscience isn’t needed to know that food commercials influence children’s choices of what to eat and how determinedly to demand it. If those ads for sugary, fatty, high-sodium, low-fiber and fun-to-eat products didn’t work, the food and beverage industry wouldn’t be spending $2 billion per year to create and place them.  

Nevertheless, a small but fascinating fMRI study has shown how such marketing may actually alter neurobiologic and psychological mechanisms in the brains of children making food decisions.

Amanda Bruce, PhD, of the University of Kansas and colleagues scanned the brains of 23 subjects between 8 and 14 years old as the youngsgters made food choices—“eat” or “not eat”—just after watching food and nonfood TV commercials.

The researchers also had the children rate the taste and perceived health value of 60 food items.

Sure enough, the ventromedial prefrontal cortex (vmPFC), a brain region associated with reward and value perception, showed increased activity at the time of food choice after watching food commercials compared with nonfood commercials.

“This shows that food commercials stimulate children’s brains in a way that nonfood commercials do not,” the authors write in a report slated for publication in an upcoming edition of the Journal of Pediatrics.

When they evaluated the children’s self-reported hunger levels in conjunction with the effects of the food commercials, the results were similarly confirming of the study’s hypothesis: The more hunger the child reported, the greater the vmPFC activity.

“These results suggest that when children are hungry, the effect of food commercials on brain activity may be particularly pronounced,” Bruce et al. write.

The team also compared how much time it took the children to make their choices. Here the results suggested that viewing food commercials may increase the propensity for children to make faster, more impulsive decisions.

Further, the failure of the foods’ respective health ratings to predict children’s choices contradicts previous findings in adult study cohorts, Bruce and colleagues point out.

“[I]n contrast to adults, children place more emphasis on the taste,” they write.

Food commercials “may prompt children to consider their liking and wanting of specific food items, irrespective of the lack of any health benefits,” the authors conclude. “This increased emphasis on taste may make it even more difficult for relevant caregivers to encourage healthy food choices. This evidence has implications for policies related to food advertising to children.”