Dietary and psych predictors of weight loss after gastric bypass

Identifying severely obese patients who will succeed after bariatric surgery remains challenging. Although numerous studies have attempted to identify preoperative patient characteristics associated with weight loss, the roles of many dietary and psychological characteristics are unclear. The purpose of this study was to examine preoperative dietary and psychological predictors of successful weight loss after bariatric surgery.

This retrospective cohort study included all patients who underwent laparoscopic Roux-en-Y gastric bypass from September 2011-June 2013 at a single institution (n = 124). Patient demographics, comorbidities, dietary and psychological factors, and weight loss outcomes were extracted from the electronic medical record. Bivariate associations between these factors and successful weight loss (≥50% excess body weight) were examined. Factors significant at P ≤ 0.1 were included in a multivariate logistic regression model.

On bivariate analysis, absence of either type 2 diabetes or hypertension, preoperative weight <270 lbs, no intentional past weight loss >50 lbs, no previous purging or family history of obesity, and no soda consumption preoperatively were associated with successful weight loss (P < 0.1). On multivariate analysis, successful weight loss was inversely associated with the presence of type 2 diabetes (odds ratio [OR], 0.22, 95% confidence interval [CI], 0.06-0.73), maximum intentional past weight loss >50 lbs (OR, 0.12 [95% CI, 0.04-0.43]), and decreasing soda consumption by >50% (OR, 0.27 [95% CI, 0.08-0.99]).

Patients with type 2 diabetes mellitus, significant previous weight loss, and poor soda consumption habits are more likely to experience suboptimal weight loss after bariatric surgery. Additional preoperative counseling and close postoperative follow-up is warranted for these patients.