The Study
Correlation between physiological and biochemical variables during short term adequate protein intake combined with resistance exercise in sedentary adults
This study is like a fair test where two groups of people did the same workouts, but one group got a special protein drink and the other got a fake one. After 4 weeks, the protein group got stronger and built more muscle — so we can say the protein drink probably helped. But we can't say it's the only way to get stronger, or that it works for everyone.
Analysis score
Maximum 90 for a randomized controlled trial.
Where the score came from
People who lifted weights and drank a protein shake 3 times a day got stronger and had less fat in their liver than people who only lifted weights.
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.
- 1Yes — gaining muscle and reducing liver fat are meaningful health improvements, even if testosterone dropped, which may just be the body adjusting.
- 2Muscle mass went up (p < 0.05), strength increased by 1.022 effect size, IGF-1 rose (p < 0.05), liver fat dropped more (p < 0.0001), and testosterone fell (p < 0.01) in the protein group.
Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data
Publication
Journal
Scientific Reports
Year
2025
Authors
Kyung-Wan Baek, Jong-Hwa Won, Chae-Been Kim, Jung-Jun Park
Related Content
Claims (7)
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.
Sedentary adults who do resistance training and take 1.5 grams of whey protein per kilogram of body weight daily for four weeks experience larger decreases in liver fat and liver enzyme levels than those who do resistance training alone.
In sedentary adults, four weeks of resistance training alone lowers levels of free fatty acids in the blood, but adding daily whey protein supplementation at 1.5 grams per kilogram of body weight prevents this reduction.
In sedentary adults who perform resistance exercise, taking 1.5 grams of whey protein per kilogram of body weight daily for four weeks results in higher levels of insulin-like growth factor 1 in the blood compared to performing resistance exercise without whey protein.
Sedentary adults who do resistance training and take 1.5 grams of whey protein per kilogram of body weight daily for four weeks gain more muscle mass and strength in their leg muscles than those who do resistance training alone.
Protein and healthy fats are required for the normal operation of human biological systems.
Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.