Supporting Weight Management during COVID-19 (SWiM-C): twelve-month follow-up of a randomised controlled trial of a web-based, ACT-based, guided self-help intervention
Acknowledgements: We thank all staff from the MRC Epidemiology Unit Function Group Team for input into the study, particularly with regard to study coordination, data management, IT, business operations and research governance. We also thank the participants who took part in the study, the coaches who helped to deliver SWiM-C, and the members of the Patient and Public Involvement panel who reviewed study materials and helped with the development of SWiM-C. We also thank the Association for the Study of Obesity (ASO), EASO, the European Coalition for People living with Obesity (ECPO), and Obesity UK for their help with study recruitment.Objectives: We developed a guided self-help intervention (Supporting Weight Management during COVID-19, “SWiM-C”) to support adults with overweight or obesity in their weight management during the COVID-19 pandemic. This parallel, two-group trial (ISRCTN12107048) evaluated the effect of SWiM-C on weight and determinants of weight management over twelve months. Methods: Participants (≥18 years, body-mass-index ≥25 kg/m2) were randomised to the SWiM-C intervention or to a standard advice group (unblinded). Participants completed online questionnaires at baseline, four months, and twelve months. The primary outcome was change in self-reported weight from baseline to twelve months; secondary outcomes were eating behaviour (uncontrolled eating, emotional eating, cognitive restraint of food intake), experiential avoidance, depression, anxiety, stress, wellbeing and physical activity. Interventions: SWiM-C is based on acceptance and commitment therapy (ACT). Participants had access to an online web platform with 12 weekly modules and email and telephone contact with a trained, non-specialist coach. Standard advice was a leaflet on managing weight and mood during the COVID-19 pandemic. Results: 388 participants were randomised (SWiM-C: n = 192, standard advice: n = 196). The baseline-adjusted difference in weight change between SWiM-C (n = 119) and standard advice (n = 147) was −0.81 kg (95% CI: −2.24 to 0.61 kg). SWiM-C participants reported a reduction in experiential avoidance (−2.45 [scale:10–70], 95% CI: −4.75 to −0.15), uncontrolled eating (–5.52 [scale: 0–100], 95% CI: –9.67 to –1.37), and emotional eating (–4.49 [scale: 0–100], 95% CI: –7.57 to –1.42) and an increase in physical activity (8.96 [MET-min/week], 95% CI: 0.29 to 17.62) compared to standard advice participants. We found no evidence of an effect on remaining outcomes. No adverse events/side effects were reported. Conclusions: Whilst we were unable to conclude that the intervention had an effect on weight, SWiM-C improved eating behaviours, experiential avoidance and physical activity. Further refinement of the intervention is necessary to ensure meaningful effects on weight prior to implementation in practice. Trial registration number: ISRCTN 1210704
