Among normal-weight women with obesity and low protein intake, consuming soy-enriched high-protein snacks for six months leads to a 1.2 kg gain in skeletal muscle mass, while consuming fruit snacks...
Mechanism
Synthesis from 1 study
Soy protein gives the body the building blocks it needs to make more muscle, turning on a molecular signal that tells muscle cells to grow. Eating more soy also makes you feel fuller, so you eat less overall, which helps your body keep the muscle you have.
Most probable mechanism
Eating soy protein delivers essential amino acids into the blood, which turn on a cellular switch in muscle cells that tells the cell to build more muscle proteins. Over time, this causes muscle tissue to grow larger.
Soy protein digestion releases essential amino acids, including leucine, into the bloodstream
Leucine and other essential amino acids bind to receptors in skeletal muscle that activate the mTORC1 signaling complex
Activated mTORC1 phosphorylates downstream targets that enhance ribosomal activity and initiate translation of muscle proteins
Sustained elevation in muscle protein synthesis over six months leads to net accumulation of skeletal muscle mass
Less supported by current evidence, but not ruled out
Eating more protein triggers hormones that signal fullness to the brain, causing a person to eat fewer calories overall, which helps preserve muscle by preventing fat gain and metabolic stress.
Soy protein ingestion stimulates enteroendocrine cells in the intestine to release satiety hormones including CCK, GLP-1, and PYY
These hormones activate neural pathways in the brainstem and hypothalamus that reduce hunger signals
Ghrelin secretion from the stomach decreases, further reducing appetite drive
Reduced hunger leads to lower spontaneous food intake and decreased daily energy consumption
Lower energy intake prevents excess fat accumulation and reduces metabolic stress, allowing muscle mass to increase relative to total body weight
Evidence from Studies
Supporting (1)
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Contradicting (0)
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