The Claim

In healthy adults over 65 years of age, daily supplementation with 40 grams of whey protein for one year, without resistance training, has no significant effect on quadriceps muscle size, lower extremity strength, or functional capacity compared to carbohydrate supplementation.

Source: The effect of daily protein supplementation, with or without resistance training for 1 year, on muscle size, strength, and function in healthy older adults: A randomized controlled trial.

What the research says

Supports is higher

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

Supports
70score
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.

Cause and effect
1 study reviewed
In plain English

In adults over 65, taking 40 grams of whey protein daily for a year without doing strength training does not change the size of the quadriceps muscle, leg strength, or physical function compared to taking carbohydrate supplements.

See the scientific wording

In healthy adults over 65 years of age, daily supplementation with 40 grams of whey protein for one year, without resistance training, has no significant effect on quadriceps muscle size, lower extremity strength, or functional capacity compared to carbohydrate supplementation.

Why this might work

Muscle fibers grow larger and stronger only when they are pulled with enough force during movement; this force triggers a molecular switch inside muscle cells that tells the cell to build more contractile proteins. Without this pulling force, even large amounts of protein do not activate this switch, so muscles stay the same size and strength.

Verified mechanismbased on 1 study

What the research says

1 study
  1. Study: The effect of daily protein supplementation, with or without resistance training for 1 year, on muscle size, strength, and function in healthy older adults: A randomized controlled trial.

    Taking 40 grams of whey protein every day for a year didn't make older adults stronger or build bigger leg muscles — unless they also did weight training. Without exercise, the protein made no difference.

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

Fit Body Science verdict — we translate health claims into clear verdicts backed by peer-reviewed research.

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