Gastric bypass may promote weight loss in overweight partners

Following bariatric surgery, patients are expected to implement diet and lifestyle changes that may be imitated by cohabitating family members. We hypothesize that cohabitating family members will lose weight and improve their eating behavior within 1 year after surgery. In this observational prospective study, family members of patients who had gastric bypass surgery (88 partners, 20 children ≥18 years old, and 25 children between 12 and 17 years old) were repeatedly assessed. Family members were asked to assess their weight and height before and 3, 6, and 12 months following bariatric surgery, and they filled out the Dutch Eating Behavior Questionnaire. Between baseline and 1 year following surgery, 49 partners of patients who underwent gastric bypass surgery (66.2%) lost weight, 6 (8.1%) remained stable, and 19 (25.7%) gained weight. Body mass index of partners (P = .002), particularly of overweight partners (P < .001)-but not children-showed a small, significant decrease over time. No significant changes in eating behavior among partners or children were found. The study indicates that gastric bypass surgery may have a ripple effect, with body weight in partners of patients decreasing over time. However, there is considerable variation in the postoperative weight loss of partners