Preoperative predictors of adherence to dietary and physical activity recommendations and weight loss one year after surgery

Abstract Background Weight loss and weight loss maintenance vary considerably between patients after bariatric surgery. Postoperative weight gain has partially been explained by lack of adherence to postoperative dietary and physical activity recommendations. However, little is known about factors related to postoperative adherence. Objectives The aim of this study was to examine psychological, behavioral, and demographic predictors of adherence to behavior recommendations and weight loss 1 year after bariatric surgery. Setting Oslo University Hospital. Methods In a prospective cohort study, 230 patients who underwent Roux-en-Y gastric bypass were recruited from Oslo University hospital from 2011 to 2013. They completed a comprehensive questionnaire before and 1 year after surgery. Weight was measured preoperatively, on the day of surgery, and 1-year postoperatively. Results Mean body mass index was 44.9 kg/m 2 (standard deviation [SD] = 6.0) preoperatively and 30.6 kg/m 2 (SD = 5.2) 1 year after surgery. Patients lost on average 29.2 % (SD = 8.2) of their initial weight. Predictors of dietary adherence were years with dieting experience, readiness to limit food intake, and night eating tendency. Preoperative physical activity and planning predicted postoperative physical activity whereas predictors of weight loss were higher frequency of snacking preoperatively, greater past weight loss, and lower age. Conclusion Several preoperative psychological predictors were related to postoperative adherence to dietary and physical activity recommendations but were not associated with weight loss. Interventions targeting psychological factors facilitating behavior change during the initial postoperative phase are recommended as this might improve long-term outcomes.