Background: Overweight and obesity represent a major public health problem. While some studies indicate that a clinic-based, healthy-lifestyle program can result in significant weight loss, a systemic review of major commercial weight loss programs concluded that the evidence to support the use of such programs is minimal. While few argue for the need for weight loss in obese individuals it is important to identify factors associated with successful weight loss. These factors could include financial incentives, frequency of intervention sessions, use of adjunctive weight loss medications and supplemental diet products, and availability of group vs. individual therapy sessions. In addition, pretreatment levels of perceived and actual engagement in healthy lifestyle behaviors (self-monitoring, exercise and diet) and psychosocial factors could potentially influence weight loss success.

Purpose:The purpose of this study was to: (a) investigate whether an intensive weight management program that included funding for program expenses and use of a patient contract was associated with clinically significant weight loss in obese and morbidly obese patients and, (b) identify environmental or psychological factors associated with successful weight loss.

Methods: We compared the amount of weight loss among patients who contracted to participate in a 26-week intervention including funding to offset program expenses and a signed participation contract (called the intervention group) to the results of patients who were offered the intervention without funding support or the contract requirement (called the comparison group). Patients in both groups were referred by their physician or self referred. Archived data from patient medical records was reviewed and analyzed. We included male or female patients, 21 to 75 years of age with BMI of >30 kg/m2. The intervention group was offered funding for a wide spectrum of treatment classes except $25 material fee per 8 week class (total of $75) and signed an agreement to attend weekly treatment sessions for 26 weeks. This group also was asked to complete five questionnaires addressing psychosocial factors (Weight Loss Behaviors Perceived to be Important, Frequency of Engaging in Specific Behaviors, Social Readjustment Rating Scale, and The Hassles and Uplifts Scale). The comparison group was not offered the funding support or contract, and chose the frequency and type of intervention sessions depending on their willingness to pay and attend the treatment sessions. Assessments at baseline and end of follow-up (weeks 0 and 26) include demographic, anthropometric. lifestyle, and co-morbidity measures. During the programs, the number of therapy sessions attended, adjunctive medication use, and supplemental diet products purchased were assessed. The main outcomes were percent change in weight, BMI, and waist circumference.

Results: There were 23 men and 104 women in the intervention group (total N=T27; mean BMI=40.5 ±8.7 (SD) and 36 men and 118 women (total N=154; BMI= 39.3±7.1 (SD) in the comparison group. Both groups experienced significant decrease in weight (7.60 kg, or 6.68% from baseline for the intervention group vs. 6.23 kg or 5.84% for the comparison group) at 26 weeks using intent-to-treat analysis. Those who started with higher weight (p0.0001), attended more sessions (p=0.0050) and used adjunctive weight loss medication (p=0.0144) lost more weight. There was no significant difference in percent weight loss (p=0.7686) and percent change in BMI (p=0.7686) between the intervention and comparison groups.

In the intervention group 100 of 127 (79%) participants completed the questionnaires. Multiple regression models showed that of five psychosocial and behavioral measures only frequency of engaging in weight loss-promoting behavior (self monitoring, diet, and physical activity) (p=0.0455) were significant and independent predictors of weight loss after adjusting for baseline weight. Major life change events, frequency and intensity of daily positive and negative events (uplifts and hassles), and perceived importance of weight loss promoting behaviors did not predict outcomes.

Discussion: We found that both weight management programs successfully promoted significant weight loss (>5%) over a period of 26 weeks. The program that offered a financial incentive and required an attendance contract did not promote greater weight loss than a comparison program, but several predictors of success were identified.


School of Public Health

First Advisor

Susanne Montgomery

Second Advisor

Serena Tonstad

Third Advisor

Colwick Wilson

Fourth Advisor

Sylvia Cramer

Degree Name

Doctor of Public Health (DrPH)

Degree Level


Year Degree Awarded


Date (Title Page)




Library of Congress/MESH Subject Headings

Obesity -- Prevention; Overweight persons -- Attitudes; Weight loss -- Counseling of; Obesity, Morbid -- prevention and control; Weight Reduction Programs.



Page Count

xiii; 153

Digital Format


Digital Publisher

Loma Linda University Libraries

Usage Rights

This title appears here courtesy of the author, who has granted Loma Linda University a limited, non-exclusive right to make this publication available to the public. The author retains all other copyrights.


Loma Linda University Electronic Theses and Dissertations

Collection Website



Loma Linda University. Del E. Webb Memorial Library. University Archives