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Schmidt

Most individuals trying to lose weight will increase physical activity as part of their strategy. For many, however, adding structured exercise does not result in weight loss. Compensatory increases in eating and decreases in non-exercise physical activity appear to be significant factors limiting the effectiveness of exercise interventions.

University of Georgia College of Education researcher Michael Schmidt is now leading a study to determine whether a number of psychological and eating behavior traits predict these compensatory behavior changes – information that could be used to help tailor and target weight management exercise interventions.

The multidisciplinary study, funded by a $408,375 federal grant over two years from the National Heart, Lung and Blood Institute, is led by Schmidt, an assistant professor and graduate coordinator of the exercise science program in the COE’s department of kinesiology. Co-investigators include James MacKillop, an associate professor in Franklin College of Arts & Sciences’ department of psychology; Ellen Evans, an associate professor of exercise science in the COE’s department of kinesiology; and Stephen Rathbun, an associate professor in the College of Public Health’s department of epidemiology and biostatistics.

Evans, MacKillop and Schmidt are participants in the Obesity Initiative at UGA. Launched in January 2012, the project advances research efforts on adult and childhood obesity and its related diseases with the aim to improve the health of Georgia’s citizens and decrease the cost of health care in the state.

While 150-250 minutes per week of moderate-intensity exercise is recommended for preventing weight gain and promoting modest weight loss, substantial inter-individual variability has been observed in the effectiveness of structured exercise to achieve expected levels of weight loss due to compensatory responses.

The multidisciplinary study is being funded by a $408,375 federal grant over two years from the National Heart, Lung and Blood Institute.

For each individual, the type and magnitude of these compensatory responses will predict the effectiveness of exercise to prevent weight gain or promote weight loss and, ultimately, cardiovascular health. Recent research has focused on the timing and magnitude of these compensatory changes in different population subgroups and across different intensities and durations of exercise. However, few studies have sought to identify the characteristics and traits that predict individual differences in the magnitude and direction of these compensatory behaviors.

The UGA study aims to: 1) identify psychological predictors of compensatory changes in diet and non-exercise physical activity in response to initiating a structured exercise program; 2) assess the relative importance of diet and activity changes in the total compensatory response; and 3) evaluate the influence of baseline body composition on compensatory changes in energy intake and expenditure.

To meet these aims, a uniformity trial comprised of a series of four identical 8-week moderate-intensity walking interventions will be conducted in a community-based sample of 120 sedentary, premenopausal women. Psychological characteristics and traits known to be related to other health behaviors (e.g. smoking, substance abuse) will be assessed at baseline and compensatory changes in energy intake and energy expenditure will be measured over the course of the intervention.

Multiple regression modeling will then be used to identify the psychological and physiological factors that explain substantial individual differences in compensatory behaviors among these women.

“The knowledge generated from this study will position the team to design a larger weight management intervention trial to explore the efficacy of a tailored approach that recognizes and attempts to manage identified psychological characteristics and traits among individuals differing in weight status,” said Schmidt