Momentary bio-behavioral predictors of loss of control eating and weight outcomes PROJECT SUMMARY/ABSTRACT Loss of control (LOC) eating is problematic for individuals with obesity due to its’ negative impact on weight loss efforts. Despite bariatric surgery being the most effective intervention for weight loss among this population, LOC eating following surgery has been repeatedly linked to poor weight outcomes. This highlights the importance of elucidating bio-behavioral mechanisms of LOC eating as an important step in improving weight outcomes following bariatric surgery. Theoretical and empirical evidence supports self-control (i.e., inhibitory control) as the mechanism through which negative affect (NA) prompts LOC eating. While traditionally measured among populations with eating disorders and obesity using retrospective self-report questionnaires, this mechanistic process has yet to be examined in real-time in the natural environment of bariatric surgery patients. Additionally, there is accumulating evidence that low blood glucose (i.e., hypoglycemia) may impact the relationship between inhibitory control and LOC eating among this population. Therefore, the proposed project seeks to test the prospective relationships between NA, inhibitory control, hypoglycemia, and LOC eating in real-time and examine their collective contribution on longitudinal weight outcomes post-bariatric surgery. Specifically, this project will test a moderated mediation model hypothesizing that momentary deficits in inhibitory control will mediate the relationship between NA and LOC eating. Further, it is hypothesized that hypoglycemia will moderate the effect between inhibitory control and LOC eating. Collectively, we anticipate that the more frequent and severe LOC eating resulting from the interplay between negative affect, inhibitory control, and hypoglycemia will then prospectively predict a poorer weight outcome over the following year. By identifying momentary mechanisms of LOC eating, this research has the potential to inform treatment intervention efforts aimed at reducing LOC eating post-surgery and promote more optimal weight outcomes.