Review of Protein Status and Body Composition After Gastric Bypass Surgery and Very-Low-Calorie Diet Therapy

Weight loss after gastric bypass surgery is induced by severe restriction of stomach capacity causing reduction in overall food intake and malabsorption of nutrients by bypassing the proximal intestine. Although relatively infrequent, protein malnutrition after gastric bypass has been reported in the literature. Definitive data are lacking on the optimal amount of dietary protein to minimize risk of protein malnutrition and to support optimal body composition changes during the rapid weight loss after surgery. This review explores the prevalence of protein malnutrition in gastric bypass patients and investigates if there is an optimal protein intake that could maximize preservation of lean body mass during rapid weight loss. The impact of diet composition on body composition changes during rapid weight loss are explored through a selected review of the literature on very low calorie diets.