The Study
Greater Protein Intake Emphasizing Lean Beef Does Not Affect Resistance Training-Induced Adaptations in Skeletal Muscle and Tendon of Older Women: A Randomized Controlled Feeding Trial
This study gave different diets to older women who did strength training and found that eating more beef protein didn't make their muscles or tendons get any stronger than eating other kinds of protein. It's like testing if adding sprinkles to ice cream makes it tastier — turns out, it didn't.
Analysis score
Maximum 90 for a randomized controlled trial.
Where the score came from
Older women did resistance training for 12 weeks and ate either normal or extra protein from beef or other sources. Researchers checked if extra protein made their muscles bigger or tendons stronger.
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 569 / 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.
- 1Extra protein didn't make muscles stronger or tendons stiffer, but it might help keep the bottom part of the knee tendon from shrinking — which could be important for preventing injury.
- 2Muscle size and strength went up for everyone, no matter how much protein they ate.
- 3The tendon at the bottom of the knee got smaller in the low-protein group but stayed the same in the high-protein group.
- 4Tendon stiffness didn't change at all.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
The Journal of Nutrition
Year
2024
Authors
Chad C. Carroll, N. W. Campbell, Rebecca L. Lewis, Sarah E. Preston, Chloe M Garrett, Hannah M. Winstone, Anna C. Barker, Johnny M. Vanos, Lucas S. Stouder, Camila Reyes, Matthew Fortino, Craig J. Goergen, Zachary J Hass, Wayne W Campbell
Related Content
Claims (6)
Healthy adults should consume 1.2 to 1.6 grams of protein per kilogram of body weight. People who do resistance training should aim for up to 1 gram of protein per pound of body weight.
After 12 weeks of strength training, the thickening of the upper and middle parts of the patellar tendon in older women increases, but the tendon's resistance to stretch and stiffness do not change, no matter how much protein is consumed.
For women aged 66 with a BMI of 28, increasing protein intake to 1.4 g/kg/day from lean beef or mixed sources while doing supervised resistance training three times per week for 12 weeks does not result in greater increases in quadriceps muscle volume or strength compared to resistance training alone with 0.8 g/kg/day protein intake.
In older women doing resistance training for 12 weeks, consuming 1.4 grams of protein per kilogram of body weight daily maintains the thickness of the tendon below the kneecap, while consuming 0.8 grams per kilogram daily results in a measurable thinning of this tendon.
Older women who do resistance training experience an increase in the thickness of their tendon tissue, and those who consume 1.4 grams of protein per kilogram of body weight per day show a larger increase, but the difference between protein intake levels is not statistically detectable in separate group comparisons.
Older women who do resistance training and consume 1.4 grams of protein per kilogram of body weight per day have higher blood urea nitrogen levels than those who consume 0.8 grams per kilogram per day, without signs of harm.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.