The Study
Physiologic and molecular bases of muscle hypertrophy and atrophy: impact of resistance exercise on human skeletal muscle (protein and exercise dose effects).
This study is like a teacher summarizing what scientists already know about how muscles grow and shrink. It doesn’t do a new experiment, so we can’t say for sure that one thing causes another — it just helps us understand the ideas that other studies have found.
Analysis score
Maximum 5 for a narrative review.
Where the score came from
Muscles stay the same size when the body makes and breaks down muscle at the same rate. Eating protein helps build muscle, and exercise boosts this effect. As people age or don’t move much, their muscles don’t respond as well to food, which can cause muscle loss.
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 51 / 100
Quality score
Based on clinical experience or non-systematic literature reviews. The lowest level of evidence as they are most susceptible to bias and personal perspective.
Key takeaways
Summary
Based on the study abstract and findings.
- 1Yes, this matters because staying active and eating protein can help prevent muscle loss as we age.
- 2Eating protein helps muscles grow.
- 3Exercise makes this effect stronger.
- 4Older or inactive people’s muscles don’t respond as well to food.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Applied physiology, nutrition, and metabolism = Physiologie appliquee, nutrition et metabolisme
Year
2009
Authors
Stuart M Phillips
Related Content
Claims (4)
Everyone can lose fat, get stronger, and build muscle with the right diet and exercise — how much they gain might differ, but the ability is there for all of us.
As we get older or if we're inactive or sick, our muscles don't build new protein as well after eating — and that's a big reason why we lose muscle, not because of changes in how our muscles work when we're not eating.
Your muscles stay the same size over time because your body constantly builds and breaks them down. Eating tips the balance toward building, while not eating tips it toward breaking down — and over time, these ups and downs balance out.
Lifting weights helps your muscles grow, especially when you eat after exercising — together, they give your muscles a big boost and help prevent muscle loss from aging or not moving enough.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.