Metabolic effects of an oral carbohydrate–whey protein supplement after fasting in volunteers: A randomized controlled crossover trial

Oral supplements containing carbohydrates (CHOs) can be used to reduce preoperative fasting time. The aim of this study was to investigate the early metabolic and acute phase responses to a clear, oral supplement containing CHO and whey protein (WP) in young, healthy volunteers during a fasting-induced organic response.In this controlled crossover clinical trial, volunteers were randomized into groups after a 12-h fast: the CHO+WP group consumed 200 mL CHO enriched with WP (n = 30); the CHO group members consumed 200 mL water plus maltodextrin (n = 30), and the Fast group was fasted only (n = 30). Blood samples were collected after fasting and 3 h after ingestion of the supplement. The samples were analyzed for glucose, glycated hemoglobin, insulin, C-reactive protein, β-hydroxybutyrate, triacylglycerols, albumin, chlorine, and sodium. After 7 d, the groups were inverted, so all volunteers entered the three groups.The nutritional intervention did not change the biochemical parameters related to the acute phase response or insulin resistance; however, there was a statistically significant reduction (P < 0.001) in serum β-hydroxybutyrate in the CHO+WP group (0.05 ± 0.08 mmol/L) compared with the other two groups (Fast group: 0.11 ± 0.08 mmol/L; CHO group: 0.09 ± 0.13 mmol/L).After overnight fasting, the oral supplement containing CHO and WP decreased ketosis. These findings may help select the most efficient oral supplement to be given 2 to 3 h before elective surgeries.