Science Center

Science-Proven Truths About the WW Program

Over the past five decades, WW has been consistently and independently proven effective. Learn more about what you can expect from the science-backed program.
Published February 1, 2021

From the very first day of WW, we have always been rooted in science. Our founder, Jean Nidetch, started her journey on an evidence-based diet from the New York City Department of Health. After trying to lose weight on her own, she discovered it was easier to succeed with others—so she created the powerful community of WW.

Related: Life-changing truths from WW's founder

For the last 57+ years, WW has continued to be one of the few commercial weight and wellness programs to scale expert guidelines for gold standard care and consistently rank high on consumer and expert recommendation lists. Researchers at Johns Hopkins University have demonstrated the effectiveness of WW as a program that helps people put public health recommendations for weight loss and healthy living into practice.

WW is backed by expert recommendations, based in science, and proven by science. Over 130 published studies, including 35 gold standard randomized trials, have demonstrated the effectiveness of WW for weight loss and wellness outcomes. WW has also been proven effective in general and clinical populations, over the long term, and across the globe.

Beyond its efficacy, WW has been shown to be a cost-effective treatment for weight management. When compared to common weight-loss medications, food replacement with a lifestyle program, or gastric balloon placement, WW had a greater cost-effectiveness. Not only that, but WW has also been proven to offer cost savings to the healthcare system.

(For a comprehensive list of published studies demonstrating WW's impact, please see our research compendium.)

WW is proven effective for sustained weight loss

  • WW is at least 2x more effective for weight loss compared to DIY approaches, physician counseling, and even gold standard clinical programs.1,2,3
  • WW is more effective for weight loss in those with prediabetes compared to a self-initiated program and produces greater improvements in glucose control.4
  • WW is proven to result in significant and sustained weight loss at not only one-year, but also two-year follow-ups. 64% of the weight lost in a 52-week WW program was maintained at two years. In addition, almost 40% of people sustained a clinically significant 5% weight loss from baseline at two-year follow up.5
  • WW is the most cost-effective nonsurgical weight loss treatment.6

WW is proven to deliver benefits beyond the scale:

Proven prevention of type 2 diabetes and proven improvements in blood sugar control for people living with diabetes and those living with prediabetes

  • Among people living with overweight and obesity, WW is proven to help prevent the development of prediabetes with a 61% relative reduction in risk, and to help normalize blood sugar levels among people living with prediabetes.7
  • Among people living with diabetes, WW is proven to deliver greater improvements in blood sugar control (measured by HbA1c levels) compared to standard care. Significantly more people in the WW program achieved clinically significant improvements in blood sugar control levels, known to reduce complications of diabetes (measured by an HbA1c level below 7%, 24% in the WW program versus 14% in a standard care program).8
  • For people living with prediabetes, WW is proven to deliver significantly greater improvements in blood sugar control compared to controls at six and 12 months.4

Proven improvements in eating behaviors

  • WW PersonalPoints™ program proven to reduce cravings by 17% and hunger by 14.7%.9

Proven improvements in weight-related quality of life

  • WW program proven to deliver improvements in quality of life by 19.4%, happiness by 4.6%, and sleep quality by 21.7%.9
  • The WW program for people living with diabetes (WW for diabetes) resulted in significantly greater improvements in weight-related quality of life compared to standard care.10

Visit the WW Science Center to learn more.


  1. Global FS trial (unpublished at present)
  2. Jebb SA, Ahern AL, Olson AD, et al. Primary care referral to a commercial provider for weight loss treatment versus standard care: A randomised controlled trial. Lancet. 2011;378(9801):1485–92.
  3. Pinto AM, Fava JL, Hoffman DA, Wing RR. Combining behavioral weight loss treatment and a commercial program: a randomized clinical trial. Obesity (Silver Spring). 2013;21(4):673-680.
  4. Marrero DG, Palmer KN, Phillips EO, Miller-Kovach K, Foster GD, Saha CK. Comparison of commercial and self-initiated weight loss programs in people with prediabetes: A randomized control trial. Am J Public Health. 2016;106(5):949-956.
  5. Ahern AL, Wheeler GM, Aveyard P, et al. Extended and standard duration weight-loss programme referrals for adults in primary care (WRAP): a randomised controlled trial. Lancet. 2017;389(10085):2214-2225.
  6. Finkelstein EA, Verghese NR. Incremental cost‐effectiveness of evidence‐based non‐surgical weight loss strategies. Clinical obesity. 2019 Apr;9(2):e12294.
  7. Ahern AL, Griffin SJ, Wheeler GM, Sharp SJ, Aveyard P, Boyland EJ, Halford JC, Jebb SA. The effect of referral to an open‐group behavioural weight‐management programme on the relative risk of normoglycemia, non‐diabetic hyperglycaemia and type 2 diabetes: Secondary analysis of the WRAP trial. Diabetes, Obesity and Metabolism. 2020 Nov;22(11):2069-76.
  8. O'Neil PM, Miller‐Kovach K, Tuerk PW, Becker LE, Wadden TA, Fujioka K, Hollander PL, Kushner RF, Timothy Garvey W, Rubino DM, Malcolm RJ. Randomized controlled trial of a nationally available weight control program tailored for adults with type 2 diabetes. Obesity. 2016 Nov;24(11):2269-77.
  9. PersonalPoints trial. Six-month single-arm trial conducted by the University of Connecticut (PI: Sherry Pagoto, unpublished at present)
  10. Holland-Carter L, Tuerk PW, Wadden TA, Fujioka KN, Becker LE, Miller-Kovach K, Hollander PL, Garvey WT, Weiss D, Rubino DM, Kushner RF. Impact on psychosocial outcomes of a nationally available weight management program tailored for individuals with type 2 diabetes: results of a randomized controlled trial. Journal of Diabetes and its Complications. 2017 May 1;31(5):891-7.