Do carbs or extra amino acids make protein work better for muscles?
Addition of carbohydrate or alanine to an essential amino acid mixture does not enhance human skeletal muscle protein anabolism.
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
Surprising Findings
Adding 30g of sugar didn’t improve muscle growth despite doubling insulin levels.
Common fitness advice says carbs boost protein absorption and insulin spikes help build muscle—but this study shows insulin doesn’t enhance the anabolic effect of EAA in healthy young adults.
Practical Takeaways
Skip the sugary protein shakes—just take 10g of EAA or a high-quality protein source (like whey) post-workout without added carbs.
Not medical advice. For informational purposes only. Always consult a healthcare professional. Terms
Surprising Findings
Adding 30g of sugar didn’t improve muscle growth despite doubling insulin levels.
Common fitness advice says carbs boost protein absorption and insulin spikes help build muscle—but this study shows insulin doesn’t enhance the anabolic effect of EAA in healthy young adults.
Practical Takeaways
Skip the sugary protein shakes—just take 10g of EAA or a high-quality protein source (like whey) post-workout without added carbs.
Publication
Journal
The Journal of nutrition
Year
2013
Authors
E. Glynn, C. Fry, K. Timmerman, M. Drummond, E. Volpi, B. Rasmussen
Related Content
Claims (6)
Even though sugar and alanine make insulin go up, that doesn’t stop your muscles from breaking down any more than protein alone does.
Adding sugar or alanine to a protein drink doesn't make your muscles grow more than the protein drink alone in healthy young people.
A small protein shake makes your muscles start growing, but adding sugar or alanine doesn’t make it grow any faster or stronger.
The protein signal that tells your muscles to grow (mTOR) turns on just as well with plain protein as it does with protein plus sugar or alanine.
Protein plus alanine keeps your muscles in 'build mode' a little longer than protein alone, but the total amount built is the same.