A Ketone Ester Drink Increases Postexercise Muscle Glycogen Synthesis in Humans.
Level 2 - randomized trial
Randomized crossover trial in humans
PubMed 28398950 · doi:10.1249/MSS.0000000000001292
What was done
Twelve well-trained male athletes completed a randomized, blinded, three-arm crossover recovery study following an interval-based glycogen depletion exercise protocol. Recovery interventions lasted 2 h under three conditions: taste-matched zero-calorie control drink followed by saline infusion, control drink followed by a 10-mM hyperglycemic clamp, or ketone monoester drink followed by a 10-mM hyperglycemic clamp. Skeletal muscle glycogen content was measured via vastus lateralis biopsies taken before and after the 2-h clamps.
What was found
The ketone ester drink increased blood D-β-hydroxybutyrate to a peak of 5.3 mM versus 0.7 mM for control (P < 0.0001). During the 2-h glucose clamps, insulin concentrations were twofold higher (31 vs 16 mU·L, P < 0.01) and glucose uptake was 32% faster (1.66 vs 1.26 g·kg, P < 0.001). Total glucose infused over 2 h increased by 61 g (258 vs 197 g), and muscle glycogen content was 50% higher (246 vs 164 mmol glycosyl units per kilogram dry weight, P < 0.05) after the ketone ester drink compared to the control drink.
Why it matters
This study shows that ketone ester ingestion combined with high circulating glucose markedly enhances postexercise insulin secretion, whole-body glucose uptake, and muscle glycogen resynthesis in humans.
Limits
The trial was limited to a small sample (n = 12) of well-trained males. Glucose was administered intravenously via a hyperglycemic clamp rather than through oral feeding, and subsequent exercise performance was not evaluated.