The Claim

Daily supplementation with 20 grams of protein for 12 weeks, regardless of whether the protein is derived from plant or dairy sources, has no significant effect on handgrip strength, leg strength, body composition, metabolic biomarkers, sleep quality, or health-related quality of life in healthy adults aged 50 years and older when compared to an isocaloric low-protein control.

Source: Impact of increased protein intake in older adults: a 12-week double-blind randomised controlled trial.

What the research says

Supports is higher

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

Supports
71score
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

Taking 20 grams of protein daily for 12 weeks from plant or dairy sources does not change handgrip strength, leg strength, body composition, metabolic biomarkers, sleep quality, or health-related quality of life in healthy adults aged 50 and older compared to a low-protein diet with the same number of calories.

See the scientific wording

Daily supplementation with 20 grams of protein for 12 weeks, whether derived from plant or dairy sources, does not significantly improve handgrip strength, leg strength, body composition, metabolic biomarkers, sleep quality, or health-related quality of life in healthy adults aged 50 years and older compared to an isocaloric low-protein control.

Why this might work

When older adults consume extra protein, their muscles do not make more protein or grow stronger because the body's ability to use amino acids for building muscle is already maxed out and does not respond to more protein. The muscles also do not change how they use energy or signal for growth, so strength, body shape, and other health measures stay the same.

Verified mechanismbased on 1 study

What the research says

1 study

  1. Study: Impact of increased protein intake in older adults: a 12-week double-blind randomised controlled trial.

    In a study where older adults took a daily protein shake for 12 weeks, whether it was from plants or milk, no one got stronger, slept better, or felt healthier than those who took a low-protein shake. So, extra protein didn’t help.

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.