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The Study

Whey Protein Supplementation During Resistance Training Augments Lean Body Mass

In simple terms

This study gave different drinks to people doing weight training and saw who gained more muscle. Because they randomly picked who got which drink, we can guess the drink might have caused the difference — but we’re not 100% sure because we don’t know if everyone was blind to what they were drinking.

48%

Analysis score

48/ 90

Maximum 90 for a randomized controlled trial.

Where the score came from

Reporting0
Methodology63
Publication100
Statistical23
Study type (basis of the score)
Randomized Controlled Trial
Level 1b - Individual RCT
What’s the bottom line?

People who drank whey protein while lifting weights gained more muscle than those who drank soy protein or sugar drinks, even when they ate the same number of calories.

Where does this study sit?

Reviews of RCTs (Meta-analyses)

Max 100

Randomized Trials

Max 90

Reviews of Cohort Studies

Max 85

Cohort Studies

Max 72

Reviews of Case-Control Studies

Max 63

Case-Control Studies

Max 58

Cross-Sectional & Case Series

Max 50

Expert Opinion

Max 5
StrongerWeaker
Randomized Trials
Level 1b
48

48 / 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.

Can establish causation

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Key takeaways

Summary

Based on the study abstract and findings.

  1. 1Yes — gaining over 3 kg more muscle than the sugar group in 9 months is a meaningful difference for someone training hard.
  2. 2Whey group gained 3.3 kg of muscle; soy group gained 1.8 kg; sugar group gained 2.3 kg.
  3. 3Whey raised blood leucine levels more than twice as much as the others.

Score breakdown, methodology, conflicts of interest, evidence analysis & raw study data

Publication

Journal

Journal of the American College of Nutrition

Year

2013

Authors

J. Volek, Brittanie M. Volk, A. Gómez, Laura J Kunces, B. Kupchak, Daniel J. Freidenreich, J. Aristizábal, Catherine Saenz, C. Dunn‐Lewis, K. Ballard, E. Quann, Diana Kawiecki, Shawn D Flanagan, Brett A. Comstock, Maren S Fragala, Jacob E. Earp, M. Fernández, Richard S. Bruno, A. Ptolemy, M. Kellogg, C. Maresh, W. Kraemer

169 citations
Analysis v5

Related Content

Claims (6)

Assertion

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.

Descriptive
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Assertion

When people consume whey protein during resistance training, their fasting blood leucine levels rise by 20% and their post-exercise blood leucine levels more than double compared to when they consume soy protein or carbohydrates, and these increases are associated with greater gains in lean body mass.

Quantitative
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Assertion

In untrained adults performing supervised resistance training for 9 months, daily whey protein supplementation leads to greater increases in lean body mass than soy protein or isocaloric carbohydrate supplementation.

Causal
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Assertion

People who consume 1.4 grams of protein per kilogram of body weight daily from whey or soy while doing resistance training for 9 months gain more lean body mass than those who consume 1.1 grams per kilogram from carbohydrates. Muscle adaptation requires protein intake above 1.1 grams per kilogram.

Causal
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Assertion

When people consume whey protein during resistance training, their fasting blood leucine levels rise by 20% and their post-exercise leucine levels more than double compared to when they consume soy or carbohydrates, and these increases are associated with greater gains in lean body mass.

Quantitative
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Assertion

People who consume 1.4 grams of protein per kilogram of body weight daily from whey or soy while doing resistance training for 9 months gain more lean body mass than those who consume 1.1 grams per kilogram from carbohydrate.

Causal
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Not medical advice. For informational purposes only. Always consult a qualified healthcare professional before making health decisions.