Preoperative inhibitory control predicts weight loss 1 year after bariatric surgery

Executive function (EF) and, in particular, inhibitory control have been associated with weight loss (WL) in behavioural WL treatment for obesity. Few studies have focused on the relationship between preoperative inhibitory control and post-operative WL following bariatric surgery, and the potential mediating role of maladaptive eating behaviours is unclear. The aim of this study was to investigate preoperative executive function as a predictor of WL at 1 year following bariatric surgery. Additionally, we aimed to explore the mediating role of postoperative compulsive grazing in the relationship between inhibitory control and WL.

A prospective observational study in which participants completed neuropsychological testing 30 days before and 1 year following surgery (n = 61/80; 76% follow-up). Participants were 80% female, with an average age of 41 years. Approximately 54% underwent gastric bypass, 26% gastric sleeve and 20% had one anastomosis gastric bypass. Regression analyses were employed to examine the relationship between preoperative EF and percentage total weight loss (%TWL), and structural equation modelling was used to examine compulsive grazing as a mediator.

After adjusting for control variables, preoperative inhibitory control explained 8% of the variance in %TWL (p ≤ 0.05). Preoperative working memory was not significantly associated with %TWL. Postoperative compulsive grazing was significantly associated with %TWL (p ≤ 0.05), but did not mediate the association between preoperative inhibitory control and %TWL.

The results suggest that preoperative inhibitory control performance is a relevant predictor of postoperative WL and that compulsive grazing is a maladaptive eating behaviour that warrants clinical attention after surgery.