Evaluating the efficacy of internet based motivational interviewing group treatment for weight loss

The Internet has the potential to reach large numbers of the population and has shown great potential for use in the area of weight loss. The overarching goal of this dissertation was to explore the use of motivational interviewing (MI) to enhance Internet behavioral weight loss programs. This investigation included two distinct studies, one eight-week pilot, and one sixteen-week intervention. In the eight-week pilot, the use of MI in online chat sessions was found to be feasible and acceptable and to produce self-motivational statements. A values discussion in addition to other MI techniques was not found to have an effect on weight loss, self-motivational statements, or autonomous motivation. The average number of self-motivational statements uttered by participants was correlated with an increase in autonomous motivation over the eight weeks (r = 0.58, p=0.05). Higher autonomous motivation at eight-weeks was associated with greater weight loss (r = -0.51, p<0.05). In the sixteen-week intervention, sixty-six females were randomized to one of two interventions, which are entitled "Minimal MI" and "Enhanced MI" throughout the description that follows. In both interventions MI techniques were used to lead an initial face-to-face weight loss session. Both groups then received a 16-week Internet behavioral weight loss program. The Enhanced MI group also received weekly online chats led using MI techniques. Weight was measured in the clinic at baseline and 16 weeks. Both study groups lost weight over time (p<0.001), the Minimal MI group lost 5.22kg (4.72) and the Enhanced MI group lost 3.71kg (4.46). Autonomous motivation measured at four weeks was a strong predictor of adherence to self-monitoring throughout the study (r=0.40, p<0.01). Self-monitoring and years of previous Internet experience predicted a significant amount of variance in 16-week weight loss (adjusted R2=0.41). These studies demonstrated the acceptability and efficacy of the use of MI in Internet behavioral weight loss interventions. Future studies should consider the use of MI to build motivation for weight loss and adherence to study procedures. (PsycINFO Database Record (c) 2010 APA, all rights reserved)