State-wide weight loss programs are increasing in popularity. For example, Shape-Up Rhode Island grew from 1738 participants in 2006, to 6815 participants in 2007. Of note is the fact that this entire program was developed and implemented by two medical students (Kumar and Weinberg) and will be financially self-sustaining by the year 2009. Other states are offering similar programs, but to date, there have been no data published on the outcomes of these interventions.
We found that 75% of Shape Up Rhode Island’s 6815 participants chose to enter the weight loss component of this program, and 70% of these individuals completed at least 12 of the 16 weeks. Those who completed the program lost an average of 3.2 kg and maintained a weight loss of 2.4 kg at six months (i.e. 76% of their initial weight loss). Among individuals who entered the program with a BMI >25 (i.e. overweight or obese), and thus were really in need of weight loss (rather than weight maintenance), self-reported weight loss averaged 3.7 kg, with 34.5% achieving a clinically significant weight loss of >5% of their initial body weight and overall weight losses (baseline to six months) averaging 2.9 kg. The objective weights suggested somewhat smaller weight loss, averaging 2.3 kg, with 25% achieving a weight loss of ≥ 5%.
Data from this study suggest that weight losses in programs such as this are modest compared to clinical programs, but given their large enrollment, may have an important public health impact. SURI was effective in producing an average decrease of −1.2 BMI units by self-report or −0.8 BMI units by objective weighing. The program was able to decrease the proportion of the population that was obese from 39% at baseline to 31% at study end. The weight losses achieved in this study would be expected to have public health benefits. Modest weight losses of 5 to 10% have been shown to reduce the incidence of diabetes by over 50%, 7, 11
with each kilogram of weight loss reducing incident diabetes by 16%, 12
and lowering systolic blood pressure by 1.0 to 2.4 mmHg. 13
Since every one unit change in body mass index reduces medical costs by 2.3%, 14
these results would yield significant savings in health care costs.
The study should be put in the context of other studies on weight loss competitions published in the 1980s. 15–18
Most of these studies were small, but they demonstrated that team competition was more effective than individual competitions both in reducing attrition and improving weight loss outcomes. In the largest of the worksite studies, Stunkard, Cohen and Felix 18
reported on 1177 employees from ten different companies who were more than 10% overweight and took part in a 12 week competition. Weight losses of these participants averaged 6.3 kg for men and 4.4 kg for women. The larger initial weight losses achieved in these early programs compared to Shape-Up RI may result from the written educational material that was provided and/or to increased accountability resulting from the weekly objective weigh-ins. At six month follow-up in three of the companies, participants were 3.2 kg below their baseline weight. Thus, they had maintained 54% of their initial weight loss compared to 76% in the current program. Shape Up Rhode Island thus suggests that such competitions can be effectively implemented via the internet on a much larger scale with similar overall results.
The dose-response relationship between pedometer steps or exercise hours and weight loss highlights the importance of the inclusion of exercise in such interventions. Exercise has been shown to be highly related to weight loss and weight loss maintenance, 19
perhaps reflecting a clustering of behavior changes, with participants who successfully change one aspect of their behavior also changing other behaviors. 20, 21
The strengths of this study include the objective assessment of weight in a subgroup of participants, the fact that 70.2% of participants completed at least 12 weeks of the program, and that six-month weight maintenance was assessed. Limitations include a study population that mainly consisted of overweight females, reflecting traditional participants in weight loss programs and the possible self-selection bias of participants in the objective weighing subgroup and the six month follow-up data. This study also is limited by the lack of a control group that did not receive the Shape-Up intervention and the inability to identify which components of this program contributed to its results. Future studies should evaluate campaigns such as Shape-Up RI using the RE-AIM framework,22–24
which assesses the Reach, Effectiveness, Adoption, Implementation and Maintenance of the program. Using this framework, greater attention would be paid to variables such as the numbers who join the program relative to those offered it and additional measures of effectiveness such as reductions in health care costs.
In conclusion, this study suggests that team-based weight loss competitions are effective at promoting modest weight loss in large numbers of participants. Hopefully this study will serve as a catalyst for other programs to report their results and begin to generate hypotheses about the components needed to increase outreach and efficacy of these interventions. Further studies should examine ways to improve such programs, possibly by including education about diet and physical activity, teaching strategies for behavior change, or providing access to health coaches.