The Claim

Long-term supplementation with plant-based protein (primarily soy) results in no statistically significant differences in upper body muscle strength, lower body muscle strength, gait speed, chair stand performance, timed up and go, or short physical performance battery scores compared to animal-based protein (primarily dairy) in adults aged 18 and older.

Source: Long-term effects of plant vs. animal protein supplementation on body composition, muscle strength, physical performance, and cardiometabolic risk factors in adults:a systematic review and meta-analysis of randomized controlled trials

What the research says

Supports is higher

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

Supports
66score
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.

Description
1 study reviewed
In plain English

In adults aged 18 and older, long-term use of plant-based protein from soy does not produce different results in muscle strength, walking speed, or physical performance tests compared to animal-based protein from dairy.

See the scientific wording

Long-term supplementation with plant-based protein (primarily soy) does not result in statistically significant differences in upper or lower body muscle strength, gait speed, chair stand performance, timed up and go, or short physical performance battery scores compared to animal-based protein (primarily dairy) in adults aged 18 and older, despite high heterogeneity and very low certainty of evidence for most outcomes.

Why this might work

The body breaks down both plant and animal proteins into the same amino acids, uses them to build and repair muscle tissue at the same rate, and maintains muscle strength and movement ability regardless of the protein source.

Supported mechanismbased on 1 study

What the research says

1 study
  1. Study: Long-term effects of plant vs. animal protein supplementation on body composition, muscle strength, physical performance, and cardiometabolic risk factors in adults:a systematic review and meta-analysis of randomized controlled trials

    When people took soy protein or dairy protein for six months or longer, both groups got just as strong and could walk, stand up, and move around equally well — so the type of protein didn’t make a 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.