PROJECT SUMMARY/ABSTRACT Elucidating the biobehavioral factors that lead to problematic eating, and ultimately increase the risk for weight gain, is critically needed given the epidemic of obesity in the United States. While the relationship between stress and problematic eating has been well-established, other factors that impact this association remain poorly understood. One important variable that appears to impact the stress-eating relationship is the manner in which one responds to stressful situations. Stress reactivity is commonly assessed by the manner in which cortisol changes in response to a stressor. For those who tend to be highly reactive to stress, in moments of high stress, they appear to be more likely to overeat. Evidence suggests that the gut microbiota influences stress reactivity, and this appears to be an important biological factor that influences the stress-eating relationship. Additionally, individuals who place a high reward value on food may be more impacted in moments of stress and may ultimately overeat or make problematic food choices in those instances. In this study, we propose to pair biological and behavioral assessment to examine the novel Biobehavioral Model of Stress-Related Eating. Through a combined laboratory and naturalistic approach, we will investigate the extent to which specific taxa and genes of the gut microbiota, stress reactivity, and the reward value of food moderate the stress-eating relationship. Through this multi-method approach, we will also use a combination of momentary and daily assessment to collect real-time data on stress and its association with dietary intake. This study will overcome limitations of prior research through its use of momentary data collection and novel pairing of biological and behavioral variables. Elucidating key factors that lead to problematic eating in moments of high stress has the potential to lead to personalized treatment approaches for weight reduction and the prevention of obesity.

PROJECT NARRATIVE The proposed project will elucidate psychological and biological variables, including stress, reward, cortisol, and the gut microbiome, that impact the day-to-day pattern of problematic eating behavior among individuals with overweight and obesity. The knowledge gained from this study will directly inform both prevention and intervention targeting problematic eating behavior that may ultimately contribute to obesity.