A Comparative Study Examining the Impact of a Protein-Enriched Vs Normal Protein Postoperative Diet on Body Composition and Resting Metabolic Rate in Obese Patients after Sleeve Gastrectomy

Background: We recently showed that an 8-week preoperative protein-enriched diet (PED) is associated with significant reductions in body weight and fat mass (FM) without significant loss of fat-free mass (FFM) in morbidly obese patients scheduled for laparoscopic sleeve gastrectomy (LSG). Objectives: The objective of this study is to evaluate the impact of PED vs a normal protein diet (NPD) on total weight loss (TWL), FM, FFM, and resting metabolic rate (RMR) in patients after LSG. Methods: Before LSG and at 3, 6, and 12 months after, we prospectively measured and compared total body weight (TBW), FM, FFM, and RMR in 60 male patients who received either a NPD (n = 30) with protein intake 1.0 g/kg of ideal body weight, or a PED (n = 30) with protein intake 2.0 g/kg of ideal body weight. Compliance in following the prescribed diet was determined with food frequency questionnaires in all patients. The impact of NPD and PED on renal function was also evaluated. Results: Despite non-significant variation in total body weight (TBW), FM decreased more significantly (p < 0.01) with the PED compared to the NPD. In addition, the PED group showed a significantly (p < 0.01) lower decrease in FFM and RMR when compared with the NPD group. Both groups showed high compliance in following the prescribed diets, without negative impact on renal function. Conclusion: PED is more effective than NPD in determining FM loss and is associated with a lower decrease in FFM and RMR, without interfering with renal function in male patients after LSG.