Exercise Effects on the Neurobiology Underlying Stress-Related Eating Behaviors in Veterans

The prevalence of overweight or obesity among Veterans was recently estimated to be 78%. Given the associations between obesity and comorbid medical conditions, increased disability levels, and reduced quality of life, this represents a significant health concern for Veterans. A contributing factor is stress, which is associated with increased rates of obesity, diabetes, and cardiovascular disease. One mechanism by which this occurs is via stress effects on eating behaviors. Stress is associated with increased food cravings, overeating, and poor nutritional choices. Stress is known to alter brain function in multiple areas and networks involved in reward processing and inhibitory function, which are highly relevant to eating behaviors. As such, identifying intervention approaches that can support stress resilience in brain regions and circuits involved in eating behaviors may be particularly helpful in reducing unhealthy eating behaviors in response to stress. An attractive candidate for this purpose is exercise. While exercise has been associated with beneficial effects on stress responsivity, the effects of endurance exercise training on stress-related eating have not been investigated. Furthermore, exercise training effects on the neurobiology underling stress-related eating behaviors are unknown. As such, the proposed study will examine how exercise training impacts the neurobiological mechanisms underlying stress-related eating. The proposed project aims to determine the effects of 12 weeks of endurance exercise training (EX), compared to a wait-list control (WL), on eating-related neurobiology during “stressed” (following a psychosocial stress task) compared to “not stressed” conditions in Veterans with overweight/obesity who report chronic stress and stress-related eating behaviors. Brain response to visual food cues will be assessed via functional magnetic resonance imaging (fMRI) at baseline and post-intervention in each stress condition. We hypothesize that EX, compared to WL, will reduce the impact of stress on the neuronal response to food cues in brain regions associated with reward processing and inhibitory function. Additionally, we hypothesize that EX- associated neuronal changes will be associated with corresponding reductions in stress responsivity during the stress task (cortisol, heart rate, subjective stress), alterations in appetite-related peptides, and diminished appetite, food ratings, and ad libitum food intake following the stress task. Given that women represent the fastest growing Veteran population, and that previous studies have observed sex-based differences in eating behaviors, brain responsivity to food cues, and overall stress responsivity, sex differences in these effects will also be examined. The proposed study will improve both our understanding of the neurobiological mechanisms underlying stress- related eating, as well as the impacts of exercise training on this neurobiology. A better understanding of these effects will support development and optimization of obesity mitigation and treatment approaches for Veterans. Additionally, understanding sex differences in the neurobiology underlying stress-related eating, and how this is affected by exercise training, will provide a mechanistic background from which to develop sex-specific treatment approaches. Given the contribution of stress-related eating to weight gain and obesity, this proposal is highly relevant to Veterans’ health and addresses the CSRD priority research areas of health-risk behaviors and women Veterans’ health. Project Number: 1I01CX002752-01A2 | Fiscal Year: 2025 | NIH Institute/Center: Veterans Affairs (VA) | Principal Investigator: Kristina Legget | Institution: VA EASTERN COLORADO HEALTH CARE SYSTEM, Aurora, CO | Activity Code: I01 | Study Section: Special Emphasis Panel[ZRD1 ENDA-L (01)] View on NIH RePORTER: https://reporter.nih.gov/project-details/11052674