Influence of dietary protein and its amino acid composition on postoperative outcomes after gastric bypass surgery: a systematic review

CONTEXT: Bariatric surgery is an effective method to reduce morbid obesity. Nutritional counseling is essential to achieve maximal treatment success and to avoid long-term complications. Increased dietary protein intake may improve various postoperative results. OBJECTIVE: The aim of this systematic review is to examine the relationship between intake of dietary protein or supplementation with amino acids and postoperative outcomes after gastric bypass surgery. DATA SOURCES: A systematic literature search was conducted in 4 electronic databases: Cochrane, Embase, PubMed, and Scopus. STUDY SELECTION: The initial search retrieved 7333 hits, which included 2390 duplicates. DATA EXTRACTION: Tweny-three studies with varying study designs, interventions, and outcomes were included. RESULTS: Studies did not provide convincing evidence of a beneficial effect on any postoperative outcome. CONCLUSIONS: The study of the influence of protein and its amino acid composition represents an important developing domain of knowledge and warrants further attention considering the popularity of bariatric surgery. Future studies should include a clear description of the quantity and composition of proteins and amino acids in the diet or supplement.