Acute ingestion of a ketone monoester, whey protein, or their co-ingestion in the overnight postabsorptive state elicit a similar stimulation of myofibrillar protein synthesis rates in young males: a double-blind randomized trial

In a randomized, double-blind, parallel group study, 36 recreationally active healthy young males received a primed continuous infusion of labelled phenylalanine and ingested ketone monoester (KET), 10 g whey protein (PRO), or both (KET+PRO). Blood and muscle biopsy samples were taken in basal and postprandial (300 minutes) conditions. Blood beta-hydroxybutyrate rose similarly in KET and KET+PRO, and plasma leucine and essential amino acid incremental area under the curve was greater in KET+PRO than in PRO or KET. All three conditions raised myofibrillar protein synthesis above basal, by 0.020, 0.014 and 0.019 percent per hour respectively, with no difference between treatments (P = 0.383), and mTORC1 pathway signaling did not differ.