Denise Wilfley, Ph.D.
Project Overview:
Over the past two decades, obesity in youth and adults has been rising in the United States at an alarming rate with current data estimating that 31% of children and adolescents ages 6-12 are classified as overweight or at risk for overweight. In spite of growing attention to this epidemic problem, little translational research has been done in the area of pediatric obesity – that is, research on how basic biological processes underlying obesity inform behavioral approaches to its treatment and prevention. Existing research on the treatment of obesity can be supplemented with basic laboratory studies exploring the biological processes that bring about dysregulated eating in obese youth. The proposed research is a translational study on habituation, a basic biological process that influences ingestive behavior in obese youth. Potential implications of the study would include applying knowledge of the habituation process to enhance and refine the eating-regulation component of existing treatment and prevention strategies.
Over a six-month period, 30 8- to 12-year-olds who are overweight (Body Mass Index [BMI] greater than the 95th percentile for age and sex) and 30 normal-weight 8- to 12-year-olds (BMI less than the 85th percentile for age and sex) will be recruited from the St. Louis metropolitan area. .Participants will be randomly assigned to one of three groups: controlled search task, automatic search task and no task. It is hypothesized that participants in the controlled search task will not habituate to food, whereas those in the automatic or no task will show a decrease in habituation across trials. In addition, we expect an interaction such that the difference among groups will be more pronounced in obese participants as compared to normal-weight participants.
Final Report:
Despite the rising prevalence of pediatric overweight, minimal research has been conducted to understand the basic biological processes underlying overweight in children. The present translational study assesses changes in physiological response (i.e., salivation) to food over time. The primary aims were to examine whether salivation patterns in children vary based on weight status and/or allocating attention to a distracter task. Participants were 30 normal weight and 30 overweight children ages 9-12. All children were presented with nine one-minute trials of a food stimulus (French fries). During each intertrial, participants either listened to sequential one-minute presentations of an audio book (distracter task) or listened to white noise (no-distracter-task control). Rates of salivation were measured using a validated procedure (the Strongin-Hinsie Peck method) and analyzed via repeated measures ANOVA. The rate of change in salivation over trials differed significantly by weight status (p = .04) but not by distracter task condition (p > .10). Specifically, regardless of distracter task condition, normal weight children habituated to food cues while overweight children did not. Results suggest that children’s physiological response to food is related to weight status. Such atypical habituation patterns could potentially lead to overconsumption, thus serving as a possible causal or maintaining factor in childhood overweight. Implications and future directions are discussed.
