What Research Says About WeightWatchers


Since its foundation in 1963, WeightWatchers has always been rooted in science. Our dedicated Science team uses credible, cutting-edge research to inform our consistently-evolving program, and works closely with the academic scientific community to ensure we meet the highest standards. WeightWatchers is committed to research that addresses knowledge gaps in the field of weight management.
Over the past four decades, over 140 studies have been published on WeightWatchers, including more than 35 publications using gold standard randomized controlled trials examining the efficacy and impact of the WeightWatchers program. The body of evidence is clear: WeightWatchers is an effective, scalable, and cost-effective program with sustained weight loss and wellness outcomes.
The research doesn’t stop here though: we’re committed to continuing to work with the scientific community to advance the scientific literature and stay up to date on the latest in weight management-related science.
Significant & Effective Weight Loss
WeightWatchers has been evaluated across the world and was found to produce significant weight loss, defined as at least 5% of body weight, across the globe including the United States, United Kingdom, Germany, China, and Australia.
In numerous randomized, controlled studies, WeightWatchers was found to be more effective for sustained weight loss—defined as 6 to 12 months—compared to:
- Do-it-yourself approaches: WeightWatchers is greater than 2 times more effective for weight loss than DIY.1
- Physician counseling: WeightWatchers is 2 times more effective for weight loss than physician counseling.2
- Professionally delivered program: WeightWatchers is 3 times more effective in producing 10 percent weight loss than professionally delivered programs.3
- Other commercial programs: Out of 141 commercial and proprietary weight-loss programs, WW was identified as one of two programs clinicians should prioritize for referral due to our sustained weight loss and cost-effectiveness.4
See below a selection of studies highlighting the efficacy of WeightWatchers:
- Tate DF, Lutes LD, Bryant M, et al. Efficacy of a Commercial Weight Management Program Compared With a Do-It-Yourself Approach: A Randomized Clinical Trial. JAMA Network Open. 2022;5(8):e2226561. doi:10.1001/jamanetworkopen.2022.26561
- Pagoto SL, Xu R, Bullard T, et al. Single arm trial of a flexible multi-component commercial digital weight management program. Ann Behav Med. 2022;56(Suppl 1):S554
- Tate DF, Quesnel DA, Lutes L, Hatley KE, Nezami BT, Wojtanowski AC, Pinto AM, Power J, Diamond M, Polzien K, Foster G. Examination of a partial dietary self‐monitoring approach for behavioral weight management. Obesity Science & Practice. 2020; 1-12.
- Morris E, Jebb SA, Oke J, Nickless A, Ahern A, Boyland E, Caterson ID, Halford J, Hauner H, Aveyard P. Effect of weight loss on cardiometabolic risk: observational analysis of two randomised controlled trials of community weight-loss programs. British Journal of General Practice. 2021 April 1;71(705):e312-9.
- Hales SB, Schulte EM, Turner TF, Malcolm R, Wojtanowski AC, Rethorst C, Pinto AM, Foster GD, O’Neil PM. Pilot evaluation of a personalized commercial program on weight loss, health outcomes, and quality of life. Translational Behavioral Medicine. 2021 Aug 16.
- Rogers RJ, Kovacs SJ, Collins KA, Raybuck S, Collins AM, Marcin ML, Foster GD, Jakicic JM. Observations of a Commercial Weight Loss Program on Physical Function and Selected CVD Risk Factors. Translational Journal of the American College of Sports Medicine. 2020 Oct 1;5(12):e000137.
- Gudzune KA, Clark JM. Role of Commercial Weight-loss Programs in Medical Management of Obesity. Endocrinology and Metabolism Clinics. 2020 June;49(2):275-287.
- Ambrosini GL, Solis-Trapala I, Ahern AL, Fuller NR, Holzapfel C, Hauner H, Caterson ID, Jebb SA. Greater improvements in diet quality among overweight participants following a group-based commercial weight loss programme than those receiving support to lose weight in primary care. Nutrition Journal. 2018; 17:64.
- Thomas JG, Raynor HA, Bond DS, et al. Weight loss and frequency of body-weight self-monitoring in an online commercial weight management program with and without a cellular-connected ‘smart’ scale: a randomized pilot study. Obesity Sci Pract. 2017;3(4):365-372.
- Jones RA, Mueller J, Sharp SJ, Vincent A, Duschinsky R, Griffin SJ, Ahern AL. The impact of participant mental health on attendance and engagement in a trial of behavioural weight management programmes: secondary analysis of the WRAP randomised controlled trial. Int J Behav Nutr Phys Act. 2021 Nov 7.
Weight-Loss Maintenance
WeightWatchers is effective as a long-term weight management strategy, producing clinically significant weight loss at two years, which is the gold standard for long-term data in the field.
In addition to our randomized controlled trial data showing maintenance of weight loss at 2-years, see below a selection of studies evaluating the behaviors of WeightWatchers weight loss maintainers who make up the WeightWatchers Global Success Registry, a growing group of 13,000+ WW members. We are consistently doing additional analyses in this group, who upon the last publication (n=6139) have lost an average of 50+ pounds and maintained it for 3.3 years.
See below a selection of studies evaluating the long-term efficacy of WeightWatchers:
- 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 normoglycaemia, non‐diabetic hyperglycaemia and type 2 diabetes: Secondary analysis of the WRAP trial. Diabetes, Obesity and Metabolism. 2020 Nov;22(11):2069-76.
- Phelan S, Halfman T, Pinto AM, Foster GD. Behavioral and Psychological Strategies of Long‐Term Weight Loss Maintainers in a Widely Available Weight Management Program. Obesity. 2020 Feb;28(2):421-8.
- Roake J, Phelan S, Alarcon N, Keadle SK, Rethorst CD, Foster GD. Sitting time, type, and context among long-term weight-loss maintainers. Obesity. 2021 May 24;29(6):1067-1073.
- Pascual RW, Phelan S, La Frano MR, Pilolla KD, Griffiths Z, Foster GD. Diet Quality and Micronutrient Intake among Long-Term Weight Loss Maintainers. Nutrients. 2019 Dec;11(12):3046.
- Phelan S, Roake J, Alarcon N, Ng SM, Glanz H, Cardel MI, Foster GD. In their own words: Topic analysis of the motivations and strategies of over 6,000 long-term weight-loss maintainers. Obesity. 2022;30:751-61.
Diabetes
WeightWatchers' diabetes-tailored plan is based on guidelines from the American Diabetes Association and the International Diabetes Federation. Both have been evaluated and found to be effective for:
Type 2 diabetes
- WeightWatchers is 2 times as effective for weight loss than standard diabetes nutrition counseling and education, and produced greater improvements in glucose control in those with type 2 diabetes.5
- Results from the six-month clinical trial evaluating the diabetes-tailored program showed clinically meaningful and statistically significant effects on weight loss, glycemic control, and reducing diabetes distress.6
Prediabetes
- WeightWatchers is 27 times more effective for weight loss than a self-initiated program and produced greater improvements in glucose control in those with prediabetes.7
- WeightWatchers is recognized by the U.S. Centers for Disease Control and Prevention (CDC) as a diabetes prevention program.
See below a selection of studies evaluating the efficacy of the WeightWatchers program for members living with diabetes and prediabetes:
- Apolzan JW, LaRose JG, Anton SD, et al. A Weight Management Program Tailored for Adults with Type 2 Diabetes: Effects on Glycemic Control. Diabetes. 2022;71(Supplement 1): 567-P.
- Schulte EM, Tuerk PW, Wadden TA, Garvey WT, Weiss D, Hermayer KL, Aronne LJ, Becker LE, Fujioka K, Miller-Kovach K, Kushner RF. Changes in weight control behaviors and hedonic hunger in a commercial weight management program adapted for individuals with type 2 diabetes. International Journal of Obesity. 2020 Jan 16:1-9.
- 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 normoglycaemia, non‐diabetic hyperglycaemia and type 2 diabetes: Secondary analysis of the WRAP trial. Diabetes, Obesity and Metabolism. 2020 Nov;22(11):2069-76.
- Palmer KNB, Saha C, Phillips EO, Krishnan A, Foster GD, Finkelstein E, Wojtanowski AC, Marrero DG. The two-year outcomes and cost-effectiveness of a commercial weight loss program for the prevention of type 2 diabetes among people with prediabetes. Endocrinology, Diabetes & Obesity. 2018; 1:5.
- O’Neil PM, Miller-Kovach K, Tuerk PW, et al. Randomized controlled trial of a nationally available weight control program tailored for adults with type 2 diabetes. Obesity (Silver Spring). 2016;24(11):2269-2277.
- Holland-Carter L, Tuerk PW, Wadden TA, et al. Impact on psychosocial outcomes of a nationally available weight management program tailored for individuals with type 2 diabetes: results of a randomized controlled trial. J Diabetes Complications. 2017;31(5):891-897.
- Piper C, Marossy A, Griffiths Z, Adegboye A. Evaluation of a type 2 diabetes prevention program using a commercial weight management provider for non-diabetic hyperglycemic patients referred by primary care in the UK. BMJ Open Diabetes Res Care. 2017;5(1):e000418.
Weight Stigma
WeightWatchers is a fierce advocate against weight stigma, bias, and discrimination and has funded, conducted, and published 10+ papers to better understand the experiences rooted in weight bias for those living in larger bodies, including consequences of stigma, with the goal of helping those affected and ultimately supporting policy-based solutions.
See below a selection of studies to better understand weight bias, stigma and discrimination:
- Pearl RL, Puhl RM, Lessard LM, Himmelstein MS, Foster GD. Prevalence and correlates of weight bias internalization in weight management: A multinational study. SSM-Population Health. 2021 Mar 1;13:100755.
- Puhl RM, Lessard LM, Himmelstein MS, Foster GD. The roles of experienced and internalized weight stigma in healthcare experiences: Perspectives of adults engaged in weight management across six countries. PloS One. 2021 June 1;16(6):e0251566.
- Puhl RM, Lessard LM, Pearl RL, Himmelstein MS, Foster GD. International comparisons of weight stigma: Addressing a void in the field. International Journal of Obesity. 2021 May 6; 1-10.
- Lessard LM, Puhl RM, Himmelstein MS, Pearl RL, Foster GD. Eating and exercise-related correlates of weight stigma: A multinational investigation. Obesity. 2021 May 24;29(6):966-970.
- Himmelstein MS, Puhl RM, Pearl RL, Pinto AM, Foster GD. Coping with weight stigma among adults in a commercial weight management sample. International Journal of Behavioral Medicine. 2020 Oct;27:576-90.
- Pearl RL, Puhl RM, Himmelstein MS, Pinto AM, Foster GD. Weight Stigma and Weight-Related Health: Associations of Self-Report Measures Among Adults in Weight Management. Annals of Behavioral Medicine. 2020.
- Pudney EV, Himmelstein MS, Puhl RM, Foster GD. Distressed or not distressed? A mixed methods examination of reactions to weight stigma and implications for emotional wellbeing and internalized weight bias. Social Science & Medicine. 2020 Mar 1;249:112854.
- Pearl RL, Himmelstein MS, Puhl RM, Wadden TA, Wojtanowski AC, Foster GD. Weight bias internalization in a commercial weight management sample: prevalence and correlates. Obesity Science & Practice. 2019 Aug;5(4):342-53.
- Puhl RM, Himmelstein MS, Pearl RL, Wojtanowski AC, Foster GD. Weight Stigma Among Sexual Minority Adults: Findings from a Matched Sample of Adults Engaged in Weight Management. Obesity. 2019 Nov;27(11):1906-15.
- Puhl RM, Lessard LM, Foster GD, Cardel MI. A Comprehensive Examination of the Nature, Frequency, and Context of Parental Weight Communication: Perspectives of Parents and Adolescents. Nutrients. 2022;14(8):1562. doi:10.3390/nu14081562.
Cost Effective
In a review of weight-loss programs, WeightWatchers was shown to be the most cost-effective when compared to other clinically proven nonsurgical programs such as Vtrim, Qysmia, Orlistat, and Jenny Craig.
See below a selection of studies highlighting the cost-effectiveness of the WeightWatchers program:
- Agrawal S, Wojtanowski AC, Tringali L, Foster GD, Finkelstein EA. Financial implications of New York City’s weight management initiative. PloS one. 2021 Feb 11;16(2):e0246621.
- Finkelstein EA, Verghese NR. Incremental cost‐effectiveness of evidence‐based non‐surgical weight loss strategies. Clinical obesity. 2019 Apr;9(2):e12294.
- Lymer S, Schofield D, Cunich M, Lee CM, Fuller N, Caterson I, Colagiuri S. The population cost‐effectiveness of Weight Watchers with general practitioner referral compared with standard care. Obesity. 2018 Aug;26(8):1261-9.
- 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.
Other notable research related to the WeightWatchers program:
- Bullard T, Medcalf A, Rethorst C, Foster GD. Impact of the COVID‐19 pandemic on initial weight loss in a digital weight management program: A natural experiment. Obesity. 2021 May 19.
- Forman EM, Goldstein SP, Crochiere RJ, Butryn ML, Juarascio AS, Zhang F, Foster GD. Randomized controlled trial of OnTrack, a just-in-time adaptive intervention designed to enhance weight loss. Translational behavioral medicine. 2019 Dec;9(6):989-1001.
- Newlands RS, Ntessalen M, Clark J, Fielding S, Hoddinott P, Heys SD, McNeill G, Craig LC. Pilot randomised controlled trial of Weight Watchers® referral with or without dietitian-led group support for weight loss in women treated for breast cancer: the BRIGHT (BReast cancer weIGHT loss) trial. Pilot and feasibility studies. 2019 Dec 1;5(1):24.
- Cornelius T, Gettens K, Lenz E, Wojtanowski AC, Foster GD, Gorin AA. How prescriptive support affects weight loss in weight-loss intervention participants and their untreated spouses. Health Psychol. 2018: 775-781.
- Gorin AA, Lenz EM, Cornelius T, Huedo-Medina T, Wojtanowski AM, & Foster GD. Randomized controlled trial examining the ripple effect of a nationally available weight management program on untreated spouses. Obesity. 2018; 26:499-504.
- Yancy WS, Shaw PA, Wesby L, Hilbert V, Yang L, Zhu J, Troxel A, Huffman D, Foster GD, Wojtanowski AC, Volpp KG. Financial incentive strategies for maintenance of weight loss: Results from an internet-based randomized controlled trial. Nutrition and Diabetes. 2018; 8:33.
- Baetge C, Earnest CP, Lockard B, et al. Efficacy of a randomized trial examining commercial weight loss programs and exercise on metabolic syndrome in overweight and obese women. Appl Physiol Nutr Metab. 2017;42(2):216-227.
- Bailey-Davis L, Pinto AM, Hanna DJ, Rethorst CD, Still CD, Foster GD. Qualitative inquiry with primary care providers and specialists about adult weight management care and referrals. Transl Behav Med. 2022;ibac006.
- Bates S, Norman P, Breeze P, Brennan A, Ahern A, BSc. Mechanisms of Action in a Behavioral Weight-Management Program: Latent Growth Curve Analysis. Annals of Behavioral Medicine, Volume 56, Issue 1, January 2022, Pages 64–77.
- Cáceres NA, Yu Q, Lauzon M, et al. Supplementing a widely available weight loss program with gamified inhibitory control training: A randomized pilot study. Obesity Science & Practice. 2022. doi:10.1002/osp4.617
For the full compendium of research evaluating the WeightWatchers program, please email media@ww.com