1. Introduction Obesity rates have reached epidemic proportions, with rates nearly doubling over the last four decades. Obesity increases individuals’ risk for myriad health problems and results in tremendous healthcare costs. Research on cognitive behavioral and acceptance-based treatments for weight management has shown promising results. However, further investigation is needed to uncover the complex mechanisms involved in unhealthy food-related behaviors. The present study examines the impact of emotion regulation on affect and eating behavior. Methods Participants 75 adults, ages 19 to 65, with BMI ranging from 19 to 50. Participants were excluded for self-reported diagnoses of anorexia or bulimia, active psychosis, or use of medications that affect hunger. Procedure Participants were randomly assigned to one of four emotion regulation conditions: Acceptance, Suppression, Cognitive Reappraisal or No Instruction/Control. Following an emotion induction procedure (writing a detailed narrative of their most upsetting life experience), participants were instructed to apply the appropriate strategy to cope with difficult emotions that arose. The interaction of BMI and suppression of emotions significantly predicted increased positive affect (b =.269, t(63) = 3.023, p =.004). Eating Behavior BMI and emotion regulation condition significantly predicted eating behavior, F(4, 65) = 4.718, p =.002, R 2 =.225. The interactions of BMI and emotion regulation condition did not significantly add to the model (R 2 change =.056). When BMI is held constant, suppression and cognitive reappraisal of emotion were each significant predictors of increased eating behavior compared to the No Instruction reference group (b=.592, t(65) = 4.214, p <.001; b =.368, t(65) = 2.817, p =.006). The relationship between BMI and suppression of emotion significantly predicted increased eating behavior (b =.299, t(62) = 2.167, p =.034). Discussion Participants in the suppression condition experienced increased positive affect as a function of increased BMI. This may suggest that eating is used as a strategy to suppress negative emotion and increase positive affect. This is supported by the finding that participants in the suppression condition exhibited the highest rates of eating behavior. Interestingly, irrespective of BMI, suppression and reappraisal both lead to increased eating behavior These findings suggest acceptance-based emotion regulation strategies may be particularly useful in targeting food and eating behavior Measures Pre and post measures of positive and negative affect were obtained using the Positive and Negative Affect Scale (PANAS). Eating behavior was assessed by counting the number of pieces of candy eaten by participants during the session. Participants were not informed until after completion of the session that their eating behavior was being measured. Analyses Regression analyses were conducted to assess the role of BMI and emotion regulation condition, and their interactions, in predicting the dependent variables of negative affect, positive affect, and eating behavior. When PANAS was used as the dependent variable, baseline PANAS scores were entered as covariates in the first step of the analyses. BMI (centered) and Emotion Regulation condition (dummy coded with no instruction as the reference group) were entered into the second step and the interaction terms entered into the third step. Results Positive and Negative Affect The overall model was significant with BMI, emotion regulation condition, and the BMI x condition interactions significantly predicting positive affect F(3, 63) = 3.226, p =.028. The model accounted for 70.5% of the variance in scores on the post PANAS for positive affect (R 2 =.705), with the interaction of BMI and emotion regulation condition accounting for a significant increase of 4.5% (R 2 change =.045) Impact of Emotion Regulation Styles on Affect and Eating Behavior Taryn L. Gammon, B.S., Kristin D. Whelan, M.A., Lauritz McCutcheon, M.A., Michelle E. Lopez, Ph.D., Janina Scarlet, Ph.D., Jill A. Stoddard Ph.D. California School of Professional Psychology at Alliant International University