OBJECTIVE: To assess the impact of the COVID-19 pandemic on initial weight loss during a digital weight management program. METHODS: Participants (n=866,192; 33.6+7.4kg/m2 ) who joined a digital weight management program (WW) in the first 30-weeks of 2020 (COVID-19 cohort) were compared to participants (n=624,043; 33.1+7.2kg/m2 ) who joined the same program during the same time period in 2019 (Control cohort). Weight change (%) and self-monitoring over the first 4-weeks of enrollment were compared between the cohorts. Significance was defined as meeting the criteria for a small effect (d>0.2) RESULTS: Over the 30-week enrollment period, the COVID-19 cohort experienced significantly less weight loss than the Control cohort but only for 7-weeks of enrollments. The COVID-19 cohort also had fewer days of food tracking, but only for 3 weeks of enrollments. There were no differences in the self-monitoring of weight and activity at any time between the two cohorts. CONCLUSIONS: Over a 30-week enrollment period, COVID-19 had negative effects on both weight loss and food self-monitoring, but the effects were short-lived. Those participating in evidence-based weight management programs can expect similar levels of initial weight loss as those experienced pre-pandemic.
Impact of the COVID-19 pandemic on initial weight loss in a digital weight management program: A natural experiment