Orbitofrontal cortex response to food portion size is linked with obesogenic appetitive profile in children
Authors: English Laural K. , Fearnbach S. Nicole , Lasschuijt Marlou , Wilson Stephen J. , Tanofsky‐Kraff Marian , Rolls Barbara J. , Keller Kathleen L. 
Published: June 2021

Previous neuroimaging studies have identified that obese children respond to food cues with hyperactivity in the orbitofrontal cortex (OFC), a brain region thought to function in higher order food processing, food motivation, and decision making. A risky appetitive trait profile characterized by low satiety responsiveness, faster eating rate, greater emotional overeating, and high food enjoyment is associated with obesity in children. ‐‐Some of these appetitive traits have also been previously associated with increased intake in response to large portion sizes. An important next step for obesity prevention is to identify differences in both brain and behavioral responding to food portion sizes based on appetitive traits prior to the development of obesity. A clearer understanding of these differences may also aid in the tailoring of obesity treatment efforts. We tested the hypothesis that children's satiety responsiveness, slowness in eating, emotional overeating, and food enjoyment would predict brain response in the OFC to images of food varying in portion size. Functional magnetic resonance imaging (fMRI) assessed whole‐brain activation to food images varying by portion size (Large, Small) in healthy‐weight children (n = 36, 7–10 y). Child appetitive traits were assessed with the Children's Eating Behavior Questionnaire. Random‐effects GLM was used to extract blood‐oxygen level‐dependent (BOLD) activation from the OFC in response to the contrast of Large > Small portions. The extent to which children's appetitive traits predicted OFC activation in response to Large > Small portions was tested using multiple linear stepwise regressions, adjusted for potential confounders such as BMI z‐score and rated pre‐scan fullness level. Faster eating (β = −0.45) and higher emotional overeating (β = 0.60) scores predicted greater fMRI BOLD activity to Large > Small portions in the left OFC (F=5.2, P < 0.05). Faster eating (β = −0.54) scores were also associated with the response to Large > Small portions in the right OFC(F=4.8, P < 0.05). Overall, appetitive traits (e.g., faster eating, higher emotional overeating) explained between 12 – 24% of the variance in response to portion size in the OFC. Children who were rated by parents as faster and more emotional eaters had increased activation to large portions in the OFC, a region thought to function in food decision making and motivation. Results show that the OFC response to large food portions is associated with certain appetitive traits and this could be part of the explanation for variations in susceptibility to overeating large portions of food.

Support or Funding Information

Penn State Social Sciences Research Institute. This study was supported by the National Center of Research Resources and the National Center for Advancing Translational Sciences, NIH, Grant UL1TR000127. The content is the sole responsibility of the authors and does not necessarily represent official views of the NIH. The doctoral training of the lead author was supported by the USDA Childhood Obesity Prevention Training Grant #2011‐67001‐3011. Imaging was conducted at the Penn State Social, Life, & Engineering Sciences Imaging Center (SLEIC), 3T MRI Facility