A single high-protein meal boosts muscle protein building dose-dependently until a plateau, and older men need a higher protein dose than younger men to reach it.
See the scientific wording
In healthy older men (approximately 71 years) and younger men (approximately 22 years), a single meal containing high-quality dietary protein stimulates myofibrillar protein synthesis in a dose-dependent manner up to a plateau; the relative protein dose required to reach that plateau is higher in older men than in younger men. This age-related anabolic resistance to protein feeding is stated as a key physiological mechanism contributing to sarcopenia, and it suggests that older adults may need to consume more protein per meal than current generic recommendations to optimally support muscle maintenance. The exact protein doses (grams) defining the dose-response plateau and the absolute or relative magnitude of the age difference are not reported.
Indication only — weak evidence
ObservationalOne low-scoring study points this way, but the evidence is still early.
What the research says
1 study reviewedSupporting (1)
Cross-Sectional StudyHuman2015
The study provides dose-response data showing that MPS increases with protein intake up to a plateau in both age groups, but the plateau occurs at a higher relative protein dose in older men. This supports the mechanistic claim that age-related anabolic resistance to protein feeding is a factor in sarcopenia and has implications for per-meal protein recommendations for older adults.
Contradicting (0)
No contradicting studies found yet
That doesn't mean it's settled — it just means no study has tested the opposite.
Quality-weighted scoring: we follow the GRADE framework — each study is rated High, Moderate, Low, or Very Low based on study design, methodology rigor, and risk of bias. A single high-quality RCT can outweigh several weaker observational studies.
Scores reflect study quality, not just count.
When you eat protein, your body breaks it into amino acids. These amino acids travel through your blood to your muscles. Inside the muscle, amino acids turn on a building program that makes new muscle protein. As you eat more protein, the building program turns on more strongly until it reaches its highest level. In older people, the building program is less sensitive, so they need to eat more protein at one meal to turn it on as much as younger people do.
Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting study
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A single high-protein meal boosts muscle protein building dose-dependently until a plateau, and older men need a higher protein dose than younger men to reach it.
Mechanism
1 studyEating protein gives your muscles amino acids that start a building process for new muscle. This process gets stronger as you eat more protein, until it hits a maximum. In older people, the building process is less responsive, so they need to eat more protein at one meal to get the same muscle-building effect.
When you eat protein, your body breaks it into amino acids. These amino acids travel through your blood to your muscles. Inside the muscle, amino acids turn on a building program that makes new muscle protein. As you eat more protein, the building program turns on more strongly until it reaches its highest level. In older people, the building program is less sensitive, so they need to eat more protein at one meal to turn it on as much as younger people do.
Dietary protein is digested into amino acids, which are absorbed into the bloodstream, increasing circulating concentrations of essential amino acids, especially leucine.
Amino acids are transported into skeletal muscle cells, where leucine binds to Sestrin2, relieving inhibition of GATOR2, which activates Rag GTPases and recruits mTORC1 to the lysosomal surface.
Activated mTORC1 phosphorylates p70S6K1 and 4E-BP1, promoting translation initiation and elongation, which increases myofibrillar protein synthesis.
The rate of myofibrillar protein synthesis increases with increasing protein dose until a plateau is reached, where further protein intake does not further increase synthesis.
In older men, a given protein dose produces less mTORC1 activation and lower myofibrillar protein synthesis than in younger men, so a higher relative protein dose is required to reach the same plateau.
Chronic insufficient postprandial stimulation of myofibrillar protein synthesis in older adults leads to net muscle protein breakdown, contributing to the loss of muscle mass characteristic of sarcopenia.
Evidence from Studies
Supporting (1)
Community contributions welcome
Contradicting (0)
Community contributions welcome
Score Breakdown
No multi-axis breakdown available yet. The overall Pro / Against score above is the best signal.
- No clinical evidence is available; the score reflects mechanistic plausibility only.
What Would Prove This
Per GRADE and EBM methodology, here is what ideal scientific evidence would look like to definitively prove or disprove this claim, ordered from strongest to weakest.
Systematic Review and Meta-Analysis of Protein Dose-Response for Myofibrillar Protein Synthesis in Older vs Younger Men
Systematic review with meta-analysis of randomized controlled trials in healthy older men (~71 years) and younger men (~22 years) measuring myofibrillar protein synthesis after single meals of high-quality protein across multiple doses (e.g., 0, 10, 20, 40 g), with standardized stable isotope methods and plateau determination.
Randomized Dose-Response Trial of Single-Meal Protein and Myofibrillar Protein Synthesis in Older vs Younger Men
Randomized crossover trial in healthy older men (~71 years) and younger men (~22 years); participants consume single meals with varying high-quality protein doses (e.g., 0, 10, 20, 40 g) on separate days; primary outcome myofibrillar protein synthesis measured by stable isotope infusion and muscle biopsy; dose-response curves compared between age groups.
Prospective Cohort of Per-Meal Protein Dose, Muscle Mass, and Sarcopenia in Older vs Younger Men
Prospective cohort of healthy older men (~71 years) and younger men (~22 years) with dietary assessment of per-meal protein dose at baseline and follow-up measures of muscle mass, strength, and incident sarcopenia over 3-5 years; adjusted for total protein, energy, activity, and comorbidities.
Cross-Sectional Comparison of Per-Meal Protein Intake and Muscle Outcomes by Age
Cross-sectional study measuring habitual per-meal protein intake and muscle mass or strength in healthy older men (~71 years) and younger men (~22 years); analysis of age-by-protein-dose interaction on muscle outcomes.
Aged Rodent Model of Protein Dose-Response for Muscle Protein Synthesis
Aged vs young male rodents receive single meals with graded high-quality protein doses; myofibrillar protein synthesis measured by stable isotope incorporation; dose-response curves and cellular signaling (e.g., mTORC1) compared.