The PRIDE study demonstrated effective weight maintenance outcomes at 18 months with similarly positive results achieved by the traditional skill-based approach and the novel motivation-focused program. The final 18-month weight loss average of −5.5% among women in the skill-based group is comparable to outcomes reported for the Diabetes Prevention Program (40
) and other behavioral obesity programs (5
). Thus, the skill-based approach implemented in the current study reflected best practices of obesity treatment clinical trials, and the finding that the motivation-focused approach was as effective as the successful standard skill-based method suggests that this novel weight maintenance program offers a viable evidence-based alternative approach for weight maintenance.
The pursuit of strategies to enhance weight maintenance has been a pressing challenge for obesity researchers. Although the novel maintenance program did not result in superior outcomes than the standard skills approach, the success of this new motivationally-based approach provides clinicians and researchers with an attractive intervention alternative to utilize when addressing the challenge of sustaining weight loss. To maximize the clinical utility of this novel approach, further research is warranted to identify whether some women prefer one approach over the other and if congruence between preference and treatment approach has any implications for success in weight maintenance.
Prior studies have examined specific motivational components in weight loss or weight maintenance programs, but to our knowledge, this is the first study to examine a theory-based weight maintenance program that incorporates multiple motivational strategies. The intervention demonstrated some of the anticipated benefits in targeted motivational constructs in the program. The specific focus on eliciting personalized reasons for behavior change, a central feature of the motivation-focused program, resulted in sustained autonomous self regulation levels in this group. Significantly higher autonomous motivations for self regulation during maintenance in the motivation-focused group than the skill-based group would suggest that consistent and specific attention on eliciting and supporting personally-relevant motivations for weight management promoted internalization of autonomous self regulation and forestalled the decline in autonomous self regulation seen over the course of the skill-based program. Previous research with morbidly obese individuals undergoing a medically-supervised diet similarly demonstrated a relationship between autonomous self regulation and weight change (13
). However, Williams and colleagues found an association between autonomous self regulation and attendance which was not observed in the current study, perhaps reflecting the shorter, 6-month period examined in that study or greater pressure to attend their program which provided medical supervision and food. More recently, Silva and colleagues demonstrated that a self-determination theory guided weight control treatment approach that shared some characteristics with the current motivation-focused maintenance program demonstrated significantly better weight losses than a more standard health education approach (14
). Responses to several other motivational constructs changed over time in both the motivation-focused and skill-based programs, and these were associated with weight loss outcomes in both conditions. Specifically, stronger self concept as a successful weight loss maintainer and self-identity as an exerciser emerged in both groups, even though there was no explicit focus on these parameters within the skill-based program. This might be due to the fact that both maintenance groups were successful in achieving weight maintenance. Self identity theory would suggest that the more an individual engages in a behavior, the more that behavior will become central to the person’s self-concept. Inasmuch as participants in both maintenance programs were successful and engaged in appropriate weight regulation behaviors to support long-term weight maintenance, it might be expected that participants in both programs would experience changes in their self concepts. The specific efforts within the motivation-focused maintenance program to cultivate an identity as an exerciser did not confer any added benefits compared to the standard skill-based approach, perhaps because of the emphasis in both programs on sustaining a high level of physical activity (200 min/week).
The focus on progress was associated with better weight maintenance in both maintenance approaches. Interestingly, although the strategy was manifestly addressed in the motivation-focused program, it was self-initiated in the skill-based program. The beneficial impact of emphasizing progress is consistent with Rothman’s (7
) hypotheses and indicates the potential importance for this strategy in weight maintenance broadly, even in more traditional programs.
Participant treatment engagement in the skill-based maintenance program resembles that of other weight loss studies (16
). Specifically, greater attendance was significantly correlated with reduced weight regain and better overall weight loss outcomes. Interestingly, a different pattern emerged in the motivation-focused program. Attendance at sessions of the motivation-focused program was not associated with weight loss outcomes, raising a question about whether their sustained higher levels of autonomous self regulation facilitated their ability to achieve weight maintenance without the external monitoring of intervention staff. Submission of self-monitoring diaries was significantly correlated with weight loss outcomes in both the conditions; however, the relationship was much stronger in the skill-based program, accounting for 14% of the variance in weight change, compared to 5% in the motivationally-based program. The lack of association between attendance and weight loss outcomes and the minimal contribution of self-monitoring diaries to understanding the variability in weight change during maintenance in the motivation-focused program stands in stark contrast to previous literature and raises questions about whether there are different parameters that are associated with success within this novel approach. Internalization of perceived autonomous self regulation for the behaviors necessary to sustain weight loss would be argued as the mechanism of sustained behavior change by self determination theory and thus greater elucidation of this process as a potential mediator in the novel motivation-focused maintenance program is warranted. Self determination theory would further posit that supporting basic human needs of autonomy and competence are critical for sustained implementation of behavior change and therefore continued examination of the interplay between autonomy support and the cultivation of perceived competence (i.e., skill level) may be a fruitful avenue for future weight maintenance research.
Some limitations to the study must be noted. Participants were all overweight women with urinary incontinence; thus, weight maintenance outcomes may not generalize outside this population. Optimism that these results translate to overweight women more broadly can be found in the similarities between the baseline characteristics of PRIDE participants and those of other studies of overweight populations with obesity-related co-morbidities (41
). Further, the weight losses observed during the initial weight loss induction period of PRIDE are quite similar to those reported in other studies, (38
) and the weight change in the skill-based maintenance program is comparable to what has been reported by others (5
). Whether this motivation-focused intervention would also be effective among overweight men remains to be seen. Further, assessment of motivational variables was limited, with several measures consisting of single items. Despite these cautions, this novel maintenance approach offers great promise for expanding effective treatment alternatives for sustained weight control.
Future explorations of motivational maintenance approaches would benefit from a more extensive approach to assessing the range of motivational constructs and analyses examining whether these constructs mediate treatment outcomes. Furthermore, inclusion of self efficacy measures consistent with the social cognitive theory based skills building approach would permit examination of separate and combined effects of self determination theory and social cognitive theory derived constructs. Such a research agenda will further the identification of individuals most likely to benefit from motivationally-focused maintenance (or from skills-based approaches) and the mechanism(s) of action by which the interventions are effective. This will also allow further refinement of the motivational goals addressed in treatment and the strategies most likely effective in achieving them.