The Study
Postprandial muscle protein synthesis rate is unaffected by 20-day habituation to a high protein intake: a randomized controlled, crossover trial
This study tested whether eating a lot of protein for 20 days changes how your muscles use protein after eating. It found no change — so eating more protein didn't make your muscles build more. But it only tested 11 older men, so we can't say this is true for everyone.
Analysis score
Maximum 90 for a randomized controlled trial.
Where the score came from
Even if older men eat a lot more protein than recommended, their muscles don't use the extra protein to build more muscle tissue.
Where does this study sit?
Reviews of RCTs (Meta-analyses)
Max 100Randomized Trials
Max 90Reviews of Cohort Studies
Max 85Cohort Studies
Max 72Reviews of Case-Control Studies
Max 63Case-Control Studies
Max 58Cross-Sectional & Case Series
Max 50Expert Opinion
Max 572 / 100
Quality score
Participants are randomly assigned to treatment or control groups, minimizing bias. The gold standard for testing whether an intervention causes an effect.
Key takeaways
Summary
Based on the study abstract and findings.
- 1This means eating extra protein won't help older men build more muscle — the body just shunts the excess amino acids away without using them for muscle repair or growth.
- 2After eating the same meal, muscles in men eating high protein (2.1+ g/kg) didn't build more protein than those eating recommended protein (1.1 g/kg), but 2.9 μmol/min more amino acids just passed through without being used.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
European Journal of Nutrition
Year
2021
Authors
Grith Højfeldt, J. Bülow, J. Agergaard, L. Simonsen, J. Bülow, P. Schjerling, G. van Hall, L. Holm
Related Content
Claims (3)
In men around 67 years old, consuming more protein than recommended for 20 days does not increase the rate at which muscle proteins are built from dietary amino acids after a meal, compared to consuming the recommended amount.
In older men, consuming more than 2.1 grams of protein per kilogram of lean body mass for 20 days increases the amount of amino acids diverted directly from arteries to veins by 2.9 micromoles per minute compared to consuming 1.1 grams per kilogram, but this change does not result in higher muscle protein synthesis.
When total calorie intake is held constant, consuming more protein leads to greater muscle protein synthesis and less fat storage compared to consuming less protein.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.