Background: Obesity interventions are implemented at state or sub-state level in the United States (US), where only selfreported weight and height data for adults are available from the Behavioral Risk Factor Surveillance System (BRFSS). The prevalence estimates of overweight and obesity generated from self-reported weight and height from BRFSS are known to underestimate the true prevalence. However, whether this underestimation is consistent across different demographic groups has not been fully investigated. Methods: In this study, we compared the prevalence estimates of obesity (body mass index (BMI) X30 kg/m 2) and overweight (BMI X25 kg/m 2) in different demographic groups in the US from the National Health and Nutrition Examination Survey (NHANES) and BRFSS during 1999-2000. We also compared the rank orders of the obesity and overweight prevalence across different demographic groups from the two data sources. Results: Compared to NHANES, BRFSS underestimated the overall prevalence of obesity and overweight by 9.5 and 5.7 percentage points, respectively. The underestimation differed across different demographic groups: the underestimation of obesity and overweight prevalence was higher among women (13.1 and 12.2 percentage points, respectively) than among men (5.8 and À0.6 percentage points, respectively). The variation of underestimation was higher among men. A clear inverse association between educational attainment and obesity prevalence among non-Hispanic African American women was observed from BRFSS data. However, no such association was found from NHANES. While BRFSS can identify correctly the population with the highest obesity and overweight burden, it did not accurately rank the obesity and overweight prevalence across different demographic groups. Conclusion: Compared to NHANES, BRFSS disproportionately underestimates the prevalence of obesity and overweight across different gender, race, age, and education subgroups.

Branding and advertising have a powerful effect on both familiarity and preference for products, yet no neuroimaging studies have examined neural response to logos in children. Food advertising is particularly pervasive and effective in manipulating choices in children. The purpose of this study was to examine how healthy children’s brains respond to common food and other logos. A pilot validation study was first conducted with 32 children to select the most culturally familiar logos, and to match food and non-food logos on valence and intensity. A new sample of 17 healthy weight children were then scanned using functional magnetic resonance imaging. Food logos compared to baseline were associated with increased activation in orbitofrontal cortex and inferior prefrontal cortex. Compared to non-food logos, food logos elicited increased activation in posterior cingulate cortex. Results confirmed that food logos activate some brain regions in children known to be associated with motivation. This marks the first study in children to examine brain responses to culturally familiar logos. Considering the pervasiveness of advertising, research should further investigate how children respond at the neural level to marketing.