For active Weight Wins members, average long-term weight loss (12 months from commencement) is 26.4 lbs (12.1% of initial body weight). 73% of active participants had lost over 5% of initial body weight, and 56% had lost over 10% of initial body weight. Results are periodically audited and analysed by the University of Hertfordshire.
These results are significantly superior to those of other broad-based weight loss programmes which have undergone clinical trials. The most successful clinical study, of Weight Watchers (a commercial diet and support group programme), reported mean weight loss of 5.5% at 12 months for active participants, compared with 12.1% at 12 months reported by Weight Wins. (“Systematic Review: An Evaluation of Major Commercial Weight Loss Programs in the United States,” Adam Gilden Tsai and Thomas Wadden, Annals of Internal Medicine, January 2005).
Weight Wins believes that the cohorts participating in its trials do not differ fundamentally from cohorts in published trials of other interventions and results are therefore broadly comparable.
The Weight Wins intervention also appears to be the first financial incentive programme to result in long-term weight loss. Comparisons may be made with mostly short-term interventions described in the following studies:
- "Systematic Review of the use of financial incentives in treatments for obesity and overweight", V. Paul-Ebhohimhen and A. Avenell, Obesity Reviews, The International Association for the Study of Obesity, 2007;
- "A pilot study testing the effect of different levels of financial incentives on weight loss among overweight employees", Finkelstein, E.A., Linnan, L.A., Tate, D.F., & Birken, B.E., Journal of Occupational and Environmental Medicine, September 2007;
- "Financial Incentive Based Approaches for Weight Loss: A Randomized Trial", Volpp, K.G., John, L.K., Troxel, A.B. et al. Journal of the American Medical Association, December 2008
Of course, not all participants complete their plan. It was found through a random sample that participants who stopped weighing in had maintained the average weight loss at 12 months.
- Assuming that all participants who stop weighing in maintain average weight loss (last reported weight), average long-term weight loss of all Weight Wins participants (including non-completers) is 15.0 lbs (6.9% of initial body weight), with 46% having lost at least 5% of body weight.
- Assuming that lapsed participants who stop weighing in regain 50% of their weight loss, average long-term weight loss of all Weight Wins participants (including non-completers) is 12.1 lbs (5.6% of initial body weight).
- Assuming that lapsed participants regain 100% of their weight loss as a ‘worst case scenario’, average weight loss of all Weight Wins participants (including non-completers) is 9.3 lbs (4.3% of initial body weight).