In middle-to-older adults, eating a low-protein breakfast with 0.13 grams of whey or pea protein per kilogram of body weight does not change blood sugar or insulin levels compared to before eating.
Mechanism
Synthesis from 1 study
Whey protein breaks down fast and sends a strong signal to muscles to build protein, but it doesn't change blood sugar or insulin levels after eating. Pea protein does the same thing with less leucine, but still doesn't affect blood sugar or insulin.
Most probable mechanism
When whey protein is eaten, it breaks down quickly and releases a large amount of leucine into the blood. This leucine travels to muscles and turns on a specific molecular switch that tells the muscle to build more protein. This process does not change how much sugar or insulin is in the blood after eating.
Whey protein is rapidly digested in the small intestine, releasing a higher concentration of free leucine compared to pea protein due to its distinct amino acid composition and faster absorption rate.
Elevated plasma leucine increases leucine delivery to skeletal muscle, where it binds to intracellular sensors that activate the mTORC1 signaling complex.
Activated mTORC1 triggers phosphorylation of downstream targets that enhance translation initiation and ribosomal biogenesis, increasing muscle protein synthesis.
The metabolic handling of leucine and other amino acids from whey protein does not stimulate pancreatic insulin secretion or alter hepatic glucose output beyond baseline levels observed after a low-protein meal.
Evidence from Studies
Supporting (1)
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Postprandial plasma amino acid and appetite responses to a low protein breakfast supplemented with whey or pea protein in middle-to-older aged adults
Contradicting (0)
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Gold Standard Evidence Needed
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