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Journal of Obesity
Volume 2010, Article ID 171957, 4 pages
Clinical Study

Changes in Theory-Based Psychological Factors Predict Weight Loss in Women with Class III Obesity Initiating Supported Exercise

1Department of Wellness, YMCA of Metropolitan Atlanta, 100 Edgewood Avenue NE, Suite 1100, Atlanta, GA 30303, USA
2Bariatric Center, Southern Regional Health System, 33 Upper Riverdale Road SW, Suite 121, Riverdale, GA 30274-2642, USA

Received 25 November 2009; Revised 3 February 2010; Accepted 17 March 2010

Academic Editor: Serena Tonstad

Copyright © 2010 James J. Annesi and Srinivasa Gorjala. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Background. Psychological factors' effect on weight loss is poorly understood, in general, and specifically in the severely obese. Objective. To examine whether a behavioral model based on tenets of social cognitive and self-efficacy theory will increase understanding of the relationship between exercise and weight loss. Methods. Fifty-one women with severe obesity participated in a 24-week exercise and nutrition information treatment and were measured on changes in psychological factors and exercise attendance. Results. A significant portion of the variance in BMI change (adjusted for number of predictors) was accounted for by the behavioral model ( 𝑅 2 a d j = 0 . 2 3 ) . Entry of exercise session attendance only marginally improved the prediction to 0.27. Only 19% of the weight lost was directly attributable to caloric expenditure from exercise. Conclusions. Findings suggest that participation in an exercise program affects weight loss through psychological pathways and, thus, may be important in the behavioral treatment of severe obesity.