Obese kids' brains may respond more to food logos than normal weight children

Children who are obese may be more vulnerable to food advertising, a brain scanning study suggests.

Obese children showed much less brain activation than healthy weight children in control regions

Food companies market to children to establish brand recognition and loyalty. (Ted S. Warren/Associated Press)

Children who are obese may be more vulnerable to food advertising, a brain scanning study suggests.

Food and beverage companies market to children to establish brand recognition, brand preference and loyalty. Previous studies found preschoolers said foods tasted better wrapped in branded packaging than plain packaging and kids were more likely to try to influence their parents' purchases when exposed to ads.

Researchers in the U.S. suspected that children who are obese would show greater activation to food logos in the "drive" regions of the brain compared with healthy weight children.

Amanda Bruce of the psychology department at the University of Missouri-Kansas City and her colleagues looked at 10 healthy children and 10 obese children aged 10 to 14 using questionnaires measuring self-control and functional magnetic resonance imaging of brain activity.

Other corporate logos and blurred images were also tested.

Obese children showed more activation in some reward regions of the brain than the healthy weight children when shown food logos.  But that wasn't the case for the control regions of the brain.

"When shown food logos, obese children showed significantly less brain activation than the healthy weight children in regions association with cognitive control," the study's authors concluded in Friday's issue of The Journal of Pediatrics.

"This provides initial neuroimaging evidence that obese children may be more vulnerable to the effects of food advertising."

The reward areas that were activated weren’t the ones common in published research. Rather, the regions were found in older structures like the midbrain, Bruce's team said.

The researchers noted that a recent study of adults who had bariatric surgery for weight loss showed decreased activation in the midbrain in response to pleasurable food images, which those investigators thought might be related to changes in how patients perceive the reward value of food after surgery.

Bruce and her co-authors said their neurorimaging data complement the findings of behavioural studies that suggested obese children ate significantly more calories of brand-name foods compared with unbranded items, which wasn’t the case in normal weight children.

They cautioned that the study was small and the findings should be considered preliminary.

In brain scanning studies, decreased brain activation does not necessarily mean the region is working less since reduced activation occasionally shows more efficient processing. But in this case, the self-reported impulsivity scores corroborated the fMRI findings.

The research was supported by the University of Kansas Medical Center Research Institute's Clinical Pilot Program.