Pilot Testing of a Portion-Controlled, Commercially Available Diet on Presurgical Weight Loss and Metabolic Outcomes in Patients Undergoing Bariatric Surgery

Weight loss prior to bariatric surgery is often recommended, but success with weight loss varies. The current study piloted the efficacy of a structured, low-glycemic portion-controlled diet (PCD) intervention compared to usual dietary care (UDC). The study randomized 73 subjects in a 12-week, controlled, randomized design. Participants' height, weight, BMI, percent body fat, fasting lipids, and glucose were measured at baseline and after 12 weeks. Although both groups had significant BMI reductions, there were no differences based upon diet and no effect on percent body fat or metabolic outcomes (all p values > 0.10). Although patients were able to reduce their BMI through dietary intervention, losses were minimal. Both groups may have been less adherent or motivated to adopt dietary recommendations because of their upcoming bariatric surgery.