A widely available commercial weight-management program led to greater reductions in weight than an unstructured, do-it-yourself (DIY) approach, according to new data published recently in JAMA Network Open.
In a randomized clinical trial that included almost 400 adults from Canada, the United States, and the United Kingdom, participants who were assigned to WW, formerly known as Weight Watchers, lost twice as much weight as those trying to lose weight on their own. The WW group also had a greater reduction in weight circumference and was more likely to achieve a 5% weight loss.
"The research shows that a majority of diets do not result in weight loss that can be maintained across time because they are simplistic, one-size-fits-all approaches to promote initial weight loss," study author Lesley Lutes, PhD, MSc, a professor of psychology and director of the Center for Obesity and Well-Being Research Excellence at the University of British Columbia, Kelowna, Canada, told Medscape Medical News.
"Unfortunately, because of the quick-fix, restrictive recommendations, and treating obesity as simply an 'eat less and exercise more' approach, people are set up for failure in the long term," she said. "As a result, they do not get the critical health benefits, such as reduced risk of diabetes and heart disease, that can come from even modest weight loss (3% to 5%) that is maintained across time."
Given the high worldwide prevalence of obesity, people need accessible and effective treatment options to manage their weight and multiple comorbid conditions, the study authors wrote. Guidelines from professional medical societies recommend behavioral treatment as part of these programs to guide participants, and although clinic-based programs appear effective, they often have limited reach because of time, training, and financial constraints.
Commercial weight-management programs may offer an effective solution, given their greater accessibility and lower costs, the study authors wrote, but few have been rigorously evaluated. The research team chose to investigate WW because it meets US Preventive Services Task Force criteria for behavioral treatment and has shown evidence of helping participants to safely achieve modest, sustained weight loss.
The investigators conducted a randomized, parallel-group, 1-year clinical trial from June 2018 to November 2019 at the University of North Carolina at Chapel Hill in the US, the University of British Columbia at Kelowna in Canada, and the University of Leeds in the UK. They primarily focused on weight change at 3 months and 12 months for 373 participants (272 women), as well as health outcomes and quality of life measurements.
The study participants had BMIs that ranged from 25-45 (mean BMI, 33.8). About 38% of participants were aged 53-75 years, 22% were aged 44-52 years, 20% were 35-43, and 21% were 18-34. About 28% were from underrepresented racial and ethnic groups.
Participants were randomly assigned to a commercial weight-loss program or a DIY weight-loss program. In the DIY group, participants received information about common weight-loss approaches available to the public, including diet tracking and self-monitoring apps, meal plans, and physical activity recommendations. These participants were left to work on their own.
In the commercial program, participants enrolled in WW for free and were encouraged to attend weekly workshops, which included a private weight assessment and discussions about successes, problem-solving challenges, and topics related to weight loss and behavior change. They also had access to the WW app for food intake, physical activity, online chats with coaches, and an online peer community.
Notably, the WW program now includes simplified requirements for dietary self-monitoring, meaning that more than 200 foods don't need to be tracked by being weighed and measured. Instead, the program automatically assigns point values for certain foods and aims for a partial recording of food intake, which is designed to reduce the burden of self-monitoring.
Although WW funded the study, Lutes said, the research team insisted that the company not be involved with the data and said they would present the outcomes, regardless of whether the program worked. In addition, the WW sites in the US and Canada were unaware of who their typical clients were vs those enrolled in the study, and after randomizing participants, the study staff were changed so that they were blinded to the treatment condition.
"This was a true test of the program, in the real world, with no interaction or influence," Lutes said. "This allowed for us to clearly, confidently, and with authority make conclusions based on the outcomes."
By the end of the study, the retention rates were 89% for the WW group and 96% for the DIY group.
At 3 months, participants in the commercial program had an average weight loss of 3.8 kg (about 8 lb), compared with 1.8 kg (4 lb) in the DIY group.
At 12 months, those in the commercial program had an average weight loss of 4.4 kg (nearly 10 lb), compared with 1.7 kg (about 4 lb), in the DIY group.
Overall, 40.7% of participants in the commercial program achieved a weight loss of 5% of their body weight at 3 months, compared with 18.6% of those in the DIY group. At 12 months, 42.8% of those in the commercial group achieved a 5% weight loss, compared with 24.7% in the DIY group.
Lutes and colleagues are now analyzing additional results from the trial, including the uptake of treatment and any differences between people or groups based on the format, modality, and treatment elements. Lutes is also interested in understanding the interplay between mental and physical health.
"Most people in weight loss studies previously have been screened out if they had either depression, anxiety, or another serious mental health condition because they were determined to likely not do as well in treatment. We did not do that in this study," she said. "I am hoping that we will be able to make some clear recommendations about the potential benefits of treatment, regardless of mental health barriers or challenges."
"While this study is funded by the commercial weight-loss company and may be at risk of bias…the weight-loss results are encouraging and not surprising," Bradley Johnston, PhD, an associate professor of nutrition at Texas A&M University and adjunct faculty at McMaster University, told Medscape Medical News.
Johnston, who wasn't involved with this study, is also the director and co-founder of NutriRECS, an independent group of international clinical, nutrition, and public health experts. In 2020, he and his colleagues conducted a review of randomized trials of 14 popular diet programs and found that many programs result in short-term weight loss and better health outcomes. But at 12 months, those results largely disappear.
"While most randomized controlled trials evaluating interventions for weight-loss programs experience regression to the mean (dieters begin to regain their early weight loss), participants in this commercial program lost more weight at 12 months than 3 months, an encouraging finding," he said.
Johnston also expressed optimism about this trial incorporating participant-reported wellness measures, including happiness, sleep quality, and overall health-related quality of life. Although the only statistically significant change was quality of life specific to self-esteem, he noted, the average change across these measures could be important to the public, even if the numbers aren't statistically significant.
"Regardless, the authors should be applauded for measuring outcomes that matter most to the average person looking to improve their health and outlook while losing weight," he said. "My own personal opinion is that all future clinical trials should measure quality-of-life items such as esteem, anxiety, sleep quality, and dietary satisfaction, and government funding agencies should avoid funding weight-loss trials that neglect to measure these essential outcomes for clinical decision-making."
The study was funded by WW International. Several authors reported receiving grants from WW during the study, and three authors were employees or shareholders of WW during the study. The full list of disclosures can be found with the original article. Johnston reported no relevant financial relationships.
Carolyn Crist is a health and medical journalist who reports on the latest studies for Medscape, MDedge, and WebMD.
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