Preoperative inhibitory control predicts weight loss 1 year after bariatric surgery.

OBJECTIVE: 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. METHOD: 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. RESULTS: 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. CONCLUSION: 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.

Visual, Verbal and Everyday Memory 2 Years After Bariatric Surgery: Poorer Memory Performance at 1-Year Follow-Up.

Severe obesity has been associated with reduced performance on tests of verbal memory in bariatric surgery candidates. There is also some evidence that bariatric surgery leads to improved verbal memory, yet these findings need further elucidation. Little is known regarding postoperative memory changes in the visual domain and how patients subjectively experience their everyday memory after surgery. The aim of the current study was to repeat and extend prior findings on postoperative memory by investigating visual, verbal, and self-reported everyday memory following surgery, and to examine whether weight loss and somatic comorbidity predict memory performance. The study was a prospective, observational study in which participants (n = 48) underwent cognitive testing at baseline, 1 and 2 years after bariatric surgery. Repeated measures analyses of variance revealed significantly poorer visual and verbal memory performance at the 1-year follow-up, with performance subsequently returning to baseline levels after 2 years. Verbal learning and self-reported everyday memory did not show significant postoperative changes. Memory performance at 1 year was not significantly predicted by weight loss, changes in C-reactive protein levels or postoperative somatic comorbidity (Type 2 diabetes, sleep apnea, and hypertension). The study demonstrated poorer visual and verbal memory performance at 1-year follow-up that returned to baseline levels after 2 years. These findings are in contrast to most previous studies and require further replication, however, the results indicate that postoperative memory improvements following bariatric surgery are not universal. Findings suggest that treatment providers should also be aware of patients potentially having poorer memory at 1 year following surgery.

Executive Function, Eating Behavior, and Preoperative Weight Loss in Bariatric Surgery Candidates: An Observational Study.

BACKGROUND: Individual differences in executive function may influence eating behavior, weight loss (WL), and WL maintenance in obesity treatment. Executive function, which designates top-down cognitive control processes, has been related to eating behaviors which may impact weight, and has been found to be predictive of WL in both behavioral WL programs and after bariatric surgery. Currently, we lack knowledge on the role of executive function in the period before bariatric surgery. If executive function impacts eating behavior and WL in the preoperative period, it may be a target for clinical attention in this stage. OBJECTIVES: We aimed to examine the relationship between objective performance-based measures of executive function, eating patterns, and WL in the preoperative period. METHOD: Baseline data in an ongoing observational longitudinal study of bariatric surgery patients were used. Eighty patients completed neuropsychological testing and self-report questionnaires 4 weeks prior to surgery. RESULTS: We found that working memory predicted WL before surgery and inhibitory control predicted adherence to dietary recommendations. CONCLUSION: Our study indicates that executive function may play a role in short-term WL and dietary adherence prior to surgery, suggesting that executive function in the preoperative period deserves an extended research focus.