Metabolic Effects of Whey Protein Supplementation After Fasting in Volunteers

The investigators will enroll young male healthy volunteers. In this controlled crossover clinical trial, after a 12‐hour fast, subjects will be randomized to consumed either: a) 200ml of carbohydrates enriched with whey protein (CHO+WP; n=30); or b) 200ml of water plus maltodextrin (CHO group, n=30); or c) remained fasting (Fast group; n=30). Blood samples will be collected after 12h‐fast and three hours after the ingestion of the supplements (or 3h fast in Fast group) for blood glucose; glycated hemoglobin; serum insulin; C‐reactive protein; beta‐hydroxybutyrate; triglycerides; albumin; chlorine and sodium assays. After a temporal break of seven days an inversion of the groups will performed so all subjects entered in the three groups. Group CHO+P will drink a clear non‐residual supplement (698 mOsm/L) having 100% whey protein isolated from total proteins, with various vitamins (B1, B6, C, D, niacin and folic acid) with a "lemon tea" flavor (Nutren Fresh; Nestlé, São Paulo, Brazil). The formula contains no lactose or lipids; is formulated with a volume of 200ml, with a caloric density of 1.28kcal/ml; protein: 10g in 200ml of the product (100% whey protein isolate); and carbohydrate: 54g in 200ml of the product (74% glucose syrup and 26% maltodextrin); Group CHO will received a clear supplement containing 200 mL of water combined with unflavored 25 g of 100% maltodextrin (CarboCH ‐ Prodiet, Curitiba, Brazil) at 12.5% dilution (101 mOsm/kg; 95kcal/200ml). The third group (Fast group; n=10) will not consume any food or supplement.