In a 6-month randomized controlled trial of 300 Chinese adults (85% female, 48.7y, BMI 28.3 kg/m2), those in the Weight Watchers (WW) meetings and digital tools group lost significantly more weight than the nutrition education control group. Specifically, weight losses were -11.7 lbs vs -1.3 lbs, respectively.
The results, published in a 2016 issue of Obesity, also found that among those who completed the study, compared to nutrition education, those in WW were also 4.5 times more likely to lose at least 5% of their body weight (66.4% vs 14.5% respectively), and 7.9 times more likely to lose at least 10% of their body weight (33.1% vs 4.2% respectively), by 6 months.