Obesity is a significant public health concern due to the increased risk of adverse co-morbid health outcomes and associated economic strain. Weight loss is indicated for overweight/obese individuals, but unfortunately weight loss and maintenance of weight loss are challenging and often unsuccessful due to bio-behavioral adaptations which promote weight regain. There is a need to better understand the mechanisms underlying energy balance regulation so that more effective and targeted strategies can be developed. Neuroimaging techniques, specifically functional magnetic resonance imaging (fMRI), have recently been utilized to uncover information on the central-peripheral regulation of food intake behaviors in obesity and weight loss. Exercise is a promising candidate for enhanced weight loss and weight loss maintenance as it influences both energy expenditure and energy intake. However, there is insufficient research on how exercise modality, particularly resistance training, influences appetite and energy intake regulation in overweight/obese adults. Furthermore, the effects of exercise on energy intake and expenditure, and thus body mass vary greatly between individuals. It is likely that differences in the bio-behavioral indices of appetite regulation can explain this variability. The overall goal of the proposed project is to determine the effects of a 12-week resistance training intervention on neuronal, hormonal, and behavioral indices of appetite regulation and energy intake in previously sedentary, overweight/obese adults. To achieve this goal, the following measures will be completed pre- and post- intervention: 1) neuronal response to visual hedonic and non-hedonic food cues in brain regions associated with food-intake and reward processing, and intrinsic resting state networks; 2) appetite ratings; 3) appetite- related peptides; 4) eating-related behaviors; and 5) ad libitum energy intake. A secondary goal is to compare outcomes between Compensators (those in lowest tertile of fat mass loss) and Non-Compensators (those in the highest tertile of fat mass loss) in order to begin to identify factors which predict the response variation seen with body mass and appetite-related indices in response to exercise interventions. Finally, results of the present proposal will be compared to findings from an ongoing trial in our laboratory evaluating appetite regulation and energy intake in response to a 12-week aerobic exercise and non-exercise control condition in a similar population (ADA 1-14-TS-07). This will provide insight on how exercise and/or weight-loss modality may differentially influence indices of appetite and energy intake regulation. Overall, this study will provide important information on the effects of exercise, particularly resistance training, on the complex neuro-endocrine and behavioral interactions controlling food intake and energy balance, and differences between Compensators vs. Non-Compensators. This knowledge will be crucial to the development of effective and individualized weight maintenance treatment strategies and clinical guidelines for obesity management.
In order to decrease the high prevalence of obesity and its related co-morbidities, a better understanding of the bio-behavioral mechanisms affecting appetite and food intake regulation is crucial. Exercise has great potential to improve weight management efforts, but it is unknown how resistance training influences appetite regulation in overweight/obese adults. This project will determine how a 12-week resistance training intervention impacts neuronal, hormonal, and behavioral indices of appetite regulation and food intake, providing important evidence for clinical weight management guidelines and treatment strategies.
