Carbohydrates Interactions

Co-ingesting creatine with carbohydrate spikes insulin, which upregulates the sodium-dependent creatine transporter and Na+/K+ pump activity in skeletal muscle, increasing intramuscular creatine retention.

Leucine activates mTOR-driven muscle protein synthesis and stimulates insulin release. Combined with carbohydrate, the insulin response is amplified roughly 2.5-fold over carbs alone, which suppresses muscle protein breakdown and increases amino acid uptake.

Sodium and glucose share the SGLT1 cotransporter in the small intestine; their co-ingestion drives faster water absorption than either alone (the basis of oral rehydration therapy). Carbohydrate also delays gastric emptying slightly while providing exercise fuel.

Carbohydrate co-ingestion with branched-chain amino acids amplifies the insulin response, which suppresses muscle protein breakdown while leucine-driven mTOR signaling stimulates protein synthesis. Carbs also replenish glycogen depleted during training.