The Claim

Fasting plasma leucine concentrations are elevated by 20% and post-exercise plasma leucine increases more than twofold following whey protein ingestion compared to soy or carbohydrate ingestion during resistance training, and these elevations are positively correlated with lean body mass gains.

Source: Whey Protein Supplementation During Resistance Training Augments Lean Body Mass

What the research says

Supports is higher

Support is ahead, but a single strong opposing study can change this.

Supports
48score
Challenges
0score

These are independent scores, not a percentage. Higher-grade studies count more, so a single strong opposing study can outweigh several weaker ones.

Quantitative
1 study reviewed
In plain English

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.

See the scientific wording

Fasting plasma leucine concentrations are elevated by 20% and post-exercise plasma leucine increases more than twofold following whey protein ingestion compared to soy or carbohydrate during resistance training, and these elevations are positively correlated with lean body mass gains.

Why this might work

Whey protein breaks down quickly in the gut, causing a sharp rise in leucine in the blood. This leucine travels to muscles and turns on a molecular switch called mTORC1, which tells muscle cells to build more protein. More protein gets made than broken down, so muscles grow larger over time, increasing lean body mass.

Verified mechanismbased on 1 study

What the research says

1 study

  1. Study: Whey Protein Supplementation During Resistance Training Augments Lean Body Mass

    The study measured plasma leucine levels before and after exercise and supplement ingestion, finding significantly higher levels in the whey group and a positive correlation between fasting leucine and lean mass gain. This supports a biological link between leucine exposure and muscle adaptation, though correlation does not prove causation.

Score breakdown, mechanism chain, raw evidence, ideal studies needed & 1 supporting studies

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