Science-proven truths about the WeightWatchers® Program

Over the past four and a half decades, WeightWatchers has been consistently and independently proven effective. Learn more about what you can expect from the science-backed program.
Published February 1, 2021 | Updated January 10, 2023

From the very first day of WeightWatchers, we have always been rooted in science. Our founder, Jean Nidetch, started her journey with an evidence-based eating plan 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 WeightWatchers.

Related: Life-changing truths from WeightWatchers' founder

For the last 57+ years, WeightWatchers 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 WeightWatchers as a program that helps people put public health recommendations for weight loss and healthy living into practice.

WeightWatchers is backed by expert recommendations, based in science, and proven by science. Over 145 studies on WeightWatchers have been published, including more than 35 publications using gold-standard randomized trials examining the efficacy and impact of the WeightWatchers program. WeightWatchers has also been proven effective in general and clinical populations, over the long term, and across the globe.

Beyond its efficacy, WeightWatchers 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, WeightWatchers had a greater cost-effectiveness. Not only that, but WeightWatchers has also been proven to offer cost savings to the healthcare system.

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

WeightWatchers is proven effective for sustained weight loss

  • WeightWatchers is at least 2x more effective for weight loss compared to DIY approaches, physician counseling, and even gold standard clinical programs.1,2,3
  • WeightWatchers is more effective for weight loss in those with prediabetes compared to a self-initiated program and produces greater improvements in glucose control.4
  • WeightWatchers is proven to result in significant and sustained weight loss at not only one-year, but also two-year follow-ups. 63% of the weight lost in a 52-week WeightWatchers 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
  • WeightWatchers is the most cost-effective nonsurgical weight loss treatment.6

WeightWatchers 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, WeightWatchers 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, WeightWatchers is proven to deliver greater improvements in blood sugar control (measured by HbA1c levels) compared to standard care. Significantly more people in the WeightWatchers 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 WeightWatchers program versus 14% in a standard care program).8
  • For people living with prediabetes, WeightWatchers 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
  • Recent clinical trials of WeightWatchers programs have shown statistically significant reductions in cravings and hunger.9, 10, 11
  • Participants on the WeightWatchers Diabetes-Tailored Plan experienced a 13.2% decrease in hunger and significant improvements in dietary choices.
Proven improvements in weight-related quality of life and diabetes distress
  • WeightWatchers program proven to deliver improvements in quality of life by 19.4%, happiness by 4.6%, and sleep quality by 21.7%.9
  • The WeightWatchers program for people living with diabetes (WeightWatchers for diabetes) resulted in significantly greater improvements in weight-related quality of life and significant reductions in diabetes distress compared to standard care.12

Visit the WeightWatchers Science Center to learn more.