Van Loon, L. J., Saris, W. H., & Wagenmakers, A. J. (1999). Optimizing post-exercise muscle glycogen synthesis carbohydrate and amino acid/protein feedings. Medicine and Science in Sports and Exercise, 31(5), Supplement abstract 298.

On three occasions, trained cyclists (N = 8), ingested a control or either of two beverage compositions, and were tested. The beverages were:

• 0.8 g/kgBW/hr CHO (CHO condition);
• 0.8 g/kgBW/hr CHO plus 0.4g/kgBW/hr of a mixture of wheat protein, Leu, and Phe (CHO + PRO); and
• an equicaloric amount of 1.2 g/kgBW/hr of CHO (CHO + CHO).

A glycogen-depleting exercise was performed and then a muscle biopsy of the vastus lateralis was taken. Another biopsy was taken five hours later.

Plasma insulin values were significantly different in all trials, the highest being in the CHO + PRO diet condition and the lowest in the CHO condition. Net muscle glycogen was highest in the two experimental conditions and lowest in the CHO condition.

Implication. CHO ingestion should be at a concentration much greater than the recommended 0.8 g/kg/hr to achieve optimal glycogen synthesis rates. The addition of protein/amino acid to a CHO supplement accelerates glycogen synthesis.

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