Study of Nutrition and Activity in Kids

While a substantial body of research suggests that RRV is related to obesity, there is very little research on factors that contribute to the RRV of food, particularly how patterns of eating can increase or decrease the motivation to eat specific foods. Previous work has demonstrated that a subset of individuals with obesity show increases in RRV of food after repeated consumption of large portions of high energy density (HED) snack foods, which has been conceptualized as sensitization. Preliminary data suggest that sensitization of the RRV of HED food is a predictor of weight gain over time. However, more work needs to be done to address this relationship using a planned, prospective study design, using adolescent research subjects, and examining potential moderators of this relationship. The purpose of this study is to identify risk and protective factors to excess zBMI change in adolescents over time. Aim 1 was to measure the relative reinforcing value (RRV) of a preferred HED and low energy density (LED) snack food before and after 2-weeks of daily exposure. Aim 2 was to assess the RRV of exercise and sedentary activity. Hypotheses include 1) sensitization to HED food will be associated with greater zBMI at the time of testing as well as greater zBMI change over time 2) sensitization to LED food will be associated with lower zBMI at the time of testing in adolescents and less zBMI change over time. 3) Greater RRV of exercise will be protective against zBMI increases over time.