The Study
Relationship between protein intake and resistance training-induced muscle hypertrophy in middle-aged women: A pilot study.
This study shows a link between eating more protein at breakfast and gaining more muscle during weight training in a small group of middle-aged women. It doesn’t prove that eating more protein caused the muscle gain — just that the two were connected in this group.
Analysis score
Maximum 72 for a cohort study.
Where the score came from
Middle-aged women in Japan did weight training twice a week for 16 weeks. Scientists checked how much muscle they gained and how much protein they ate, especially at breakfast.
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 539 / 100
Quality score
Groups of people are followed over time to see who develops an outcome. Strong for identifying risk factors and associations, but cannot prove causation as firmly as RCTs.
Key takeaways
Summary
Based on the study abstract and findings.
- 1Yes, this matters because it shows that changing when you eat protein—like having more at breakfast—can help build muscle, even in midlife.
- 2The women gained 1.46% more muscle.
- 3Those who started with less protein at breakfast gained more muscle if they increased it.
- 4Eating more protein at breakfast over time was linked to better muscle growth.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Nutrition
Year
2022
Authors
J. Yasuda, K. Murata, Tsubasa Hasegawa, Mana Yamamura, S. Maeo, Junya Takegaki, Nobuaki Tottori, Takumi Yokokawa, R. Mori, T. Arimitsu, Shu Nishikori, S. Fujita
Related Content
Claims (5)
Most of the reason why people gain muscle at different rates isn't because of their genes—it's because of things they can change, like how hard they train, how much they eat, and how focused they are in the gym.
When doing strength training, consuming more protein leads to greater muscle growth than consuming the same amount of calories from carbohydrates or fats.
If middle-aged Japanese women eat more protein at breakfast over time while strength training, they may gain more muscle — but if they already eat a lot of protein at breakfast to start with, they might not gain as much.
Working out with weights twice a week for four months can help middle-aged Japanese women build a little more muscle, even as they get older.
If middle-aged Japanese women who are doing strength training start eating more protein at breakfast—especially if they weren’t eating much before—they’re likely to gain more muscle.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.