Abstract: Food insecurity, or the lack of sufficient food in both quality and quantity for an active and healthy life, is a pressing health issue in the United States with over 18% of adults being food insecure. Food insecurity is a risk factor for multiple chronic diseases, including obesity. Importantly, both food insecurity and obesity are more prevalent in African American (AA) women compared to other groups. Further, food insecurity is considered a `cyclic phenomenon' with episodes of food adequacy (i.e., enough food to eat) and food shortage (i.e., not enough food to eat). More research is needed to better understand why food insecurity is linked to obesity, including acknowledging the episodic nature of food insecurity as a stressor and identifying underlying mechanisms. To this end, we will examine the potential role of psychological and physiological parameters in the food insecurity-obesity linkage and do so in a health disparate population, AA women. The objective of this exploratory/developmental study is to investigate the episodic nature of food insecurity as a stressor via responses in body weight and psychological and physiological parameters longitudinally. We will enroll 30 food insecure and 30 food secure AA women (age 18-65 y) with obesity (BMI 30-50 kg/m2) to measure 1) daily body weight remotely over 22 weeks and 2) psychological and physiological parameters via clinic assessments at the beginning and end of 22 weeks. Further, we will assess episodes of food insecurity and stress on a weekly basis. All participants will be offered ride-sharing as a transportation option to and from all clinic visits. We hypothesize that food insecure AA women with obesity will demonstrate increased body weight and changes in psychological and physiological endpoints, whereas food secure AA women with obesity will not. We will also examine associations between changes in psychological and physiological parameters and changes in body weight. Psychological questionnaires will assess stress; executive function, decision-making, and motivation; and affect and non-homeostatic eating. Physiological measurements will include cortisol, DHEA-S, c-reactive protein, thyroid hormones, glucose, HbA1c, insulin, and allostatic load. We believe this will be the first study to examine changes in body weight and psychological and physiological factors in food insecure AA women with obesity during episodes of food insecurity. Findings from this study will provide a range of novel data that will be translated into well-powered follow-up grants. This study also has significant public health implications by addressing the cyclic nature of food insecurity to identify underlying mechanisms that can be targeted to mitigate the adverse relationship between FI and obesity and reduce health disparities in minority populations.