Macro partitioning

Co-ingesting protein (0.3-0.4 g/kg) with sub-optimal carbohydrate amounts (<1 g/kg/h) accelerates glycogen synthesis by augmenting insulin release, but has no additional effect when carbohydrate intake is adequate (>1 g/kg/h).

If you cannot eat enough carbohydrates after exercise (less than 1 g/kg/h), adding 0.3-0.4 g/kg of protein can help speed up glycogen recovery by boosting insulin. However, if you are already consuming sufficient carbohydrates (1 g/kg/h or more), adding protein will not further increase the rate of glycogen storage.