Food Reinforcement, Attentional Bias, and Inhibitory Control as Mechanisms of Energy Compensation with Exercise

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ABSTRACT : Food Reinforcement, Attentional Bias, and Inhibitory Control as Mechanisms of Energy Compensation with Exercise Over 70% of Americans are either overweight or obese, putting them at risk for many chronic diseases such as cardiovascular disease, diabetes, and certain cancers. Effective weight loss and weight loss maintenance strategies have thus become a prime public health importance, with exercise becoming the most common weight loss treatment. However, weight loss efforts through exercise are often thwarted by compensatory responses working to conserve energy. This act of energy compensation is a way the human body maintains energy homeostasis, resisting maintenance of the negative energy balance required for weight loss. Compensatory responses are evolutionarily conserved traits, where the human body assumes a negative energy balance is indicative of food shortage and thus a threat to survival. This was indeed a desirable trait in times of food shortage; however, these responses currently resist the much needed weight reduction in our modern obesogenic environment. Therefore, exercise-induced weight loss is often much less than expected. Our preliminary research, in agreement with others, point to increases in energy intake as the primary compensatory response when exercising for weight loss; however, mechanisms promoting this behavior have yet to be fully elucidated. With the prevalence of obesity and its related comorbidities continually rising, novel and innovative research is needed to expose factors contributing to weight loss resistance and the regain of lost weight. The purpose of this pilot study is to identify novel mechanisms working to influence energy intake when exercising for weight loss. A commonly assumed mechanism responsible for the increased drive for greater energy intake with exercise is increased hunger. However, research on the influence of exercise on hunger and appetite-regulating hormones is mixed; with evidence demonstrating long-term exercise actually improves the satiety response to a meal. Compensatory increases in energy intake have also been observed independent of changes in hunger, pointing to other factors that increase the drive to eat as likely mechanisms responsible for this compensatory response to an exercise-induced energy deficit. The reinforcing value of food is a strong predictor of body weight and energy intake independent of hunger, although not previously studied as a factor in energy compensation with exercise. A greater attentional processing towards food, termed attentional bias, is integral in the development of food reinforcement. Overeating occurs when the motivational wanting of food exceeds the capacity for inhibitory control for eating. As such, impaired inhibitory control strengthens the positive relationship between food reinforcement, attentional bias and greater energy intake. Elucidating the role these behavioral mediators of energy intake play in energy compensation to an exercise-induced energy deficit could lead to the development of novel, evidence-based interventions that work to attenuate the compensatory response to exercise, improving its efficacy for weight control and thus offering a more effective obesity treatment option. The present study will use a counterbalanced cross-over design to assess food reinforcement, attentional bias and inhibitory control for food cues before and after an acute bout of exercise and an acute bout of sedentary activity on two separate visits. Differences in food reinforcement, attentional bias and inhibitory control for food cues will be determined between conditions (bout of exercise vs bout of sedentary activity), time (before exercise vs. after) and sex (male vs. female). This will demonstrate if acute exercise influences the purported compensatory mechanisms and if outcomes differentiate by sex. Our central hypothesis is that engaging in an acute bout of exercise will evoke greater food reinforcement, attentional bias, and lower inhibitory control for food cues. Based on previous literature, these changes would be expected to result in greater energy intake and thus uncover novel mechanisms working to maintain energy homeostasis when exercising for weight loss. Identification of novel factors influencing weight loss with exercise are needed in order to improve exercise as an obesity treatment strategy. This need is based on the current obesity epidemic and continued lack of success in reversing this trend. Successful completion of the proposed pilot project will serve as an initial investigation into these compensatory mechanisms and set the stage for development of novel obesity treatment strategies. This pilot study is intended to serve as preliminary data to support follow-up studies demonstrating longitudinal changes in these behavioral mediators of energy intake and if these changes cause greater energy intake and impede weight loss from an exercise intervention. Additional future research will feature an exercise intervention alongside a behavioral training treatment that has been effective in attenuating attentional bias and food reinforcement or treatments known to improve inhibitory control. Successful completion of these future studies will fulfill our long-term goal, which is to make exercise a more effective weight loss treatment to reduce the incidence of obesity by developing interventions that will attenuate compensation for the energy expended through exercise. Completion of the present pilot study will be the necessary first step in this long-term goal.
StatusFinished
Effective start/end date2/1/217/31/21

Funding

  • National Institute of General Medical Sciences

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