Predictors of Lowest Weight and Long-Term Weight Regain Among Roux-en-Y Gastric Bypass Patients

Weight loss surgery (WLS) outcomes are poorly understood. This study aimed to evaluate the relationship of well-documented (e.g., health, diet, physical activity) and theoretically relevant variables (e.g., substance use and food addiction) with both weight nadir and weight regain (WR) following WLS. A sample of 97 Roux-en-Y gastric bypass patients (M (time since surgery) = 8.86 years) were surveyed about pre- and post-WLS weight, health, self-management behaviors, alcohol problems, and clinical symptoms. Patients lost a mean of 42 % (SD = 10.71 %) of total weight at weight nadir, but 26 % (SD = 19.66 %) of the lost weight was regained by the time of the survey. Correlates of lower weight nadir and WR differed considerably, with minor overlap. Weight nadir was associated with pre-WLS drug use and post-WLS medical comorbidities. WR, on the other hand, was associated with post-WLS adherence to dietary and physical activity modification. Post-WLS nocturnal eating, depression, and problematic alcohol use were also associated with WR. With all associated variables in regression models, number of post-WLS medical comorbidities (beta = -.313, p < 0.01) and post-WLS depression (beta = 0.325, p < 0.01) accounted for the most variance and remained as significant predictors of weight nadir and WR, respectively. While weight nadir was associated with relatively few and largely nonmodifiable variables, WR was significantly associated with adherence-related behaviors, mood symptoms, and pathological patterns of food and alcohol use, all of which are potentially modifiable. These findings underscore the importance of long-term behavioral and psychosocial monitoring after surgery.