Consuming carbohydrates triggers biological signals that indicate metabolic stability and promote recovery, while leucine triggers signals that indicate the presence of materials needed for repairing...
Mechanism
Synthesis from 1 study
After exercise, eating carbs tells your muscles it's safe to recover, and eating leucine tells them there's enough building material to repair. Together, they turn on a molecular switch that starts making new muscle proteins faster than either one alone.
Most probable mechanism
When you eat carbs after exercise, your body releases insulin, which tells cells it's safe to start repairing. Leucine, a building block from protein, directly signals that raw materials are available. Together, they turn on a master switch called mTOR that kicks off the machinery needed to build new muscle proteins.
Carbohydrate ingestion increases blood insulin levels, which activates the PI3K-Akt signaling pathway in muscle cells.
Insulin-mediated Akt activation leads to phosphorylation and inhibition of TSC2, relieving suppression of the mTOR complex.
Leucine enters muscle cells and activates mTOR through a separate pathway involving hVps34, independent of insulin.
Convergent signals from insulin and leucine fully activate mTOR, triggering phosphorylation of its downstream targets S6K1 and 4E-BP1.
Phosphorylated 4E-BP1 releases eIF4E, enabling formation of the translation initiation complex that binds to mRNA.
Phosphorylated S6K1 enhances ribosomal activity and increases the efficiency of protein synthesis machinery.
Activated translation machinery incorporates amino acids into new muscle proteins at an elevated rate.
Evidence from Studies
Supporting (1)
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Leucine-enriched essential amino acid and carbohydrate ingestion following resistance exercise enhances mTOR signaling and protein synthesis in human muscle.
Contradicting (0)
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