REF-911 · Hevia-Larraín et al., 2021 · Sports Medicine, Vol. · Paper · PubMed

High-Protein Plant-Based Diet Versus a Protein-Matched Omnivorous Diet to Support Resistance Training Adaptations: A Comparison Between Habitual Vegans and Omnivores

B+moderate evidenceMeasured on non-athletes and recreational peopleWritten before October 2026, being re-checked

Nineteen habitual vegan and nineteen omnivorous young men did 12 weeks of supervised resistance training twice a week, with habitual protein adjusted to 1.6 g/kg/day using soy (vegans) or whey (omnivores).

Both groups significantly gained leg lean mass, rectus femoris and vastus lateralis cross-sectional area, type I and type II fibre area and leg-press 1RM, with no between-group differences for any variable.

The authors conclude that a high-protein, exclusively plant-based diet is not different from a protein-matched mixed diet in supporting muscle strength and mass in untrained young men eating adequate protein.

Participants

Vegans (VEG): n=19 habitual vegan young men, 26 ± 5 years, 72.7 ± 7.1 kg, 22.9 ± 2.3 kg/m2.
Omnivores (OMN): n=19 young men, 26 ± 4 years, 73.3 ± 7.8 kg, 23.6 ± 2.3 kg/m2.

Protocol

12-week, twice-weekly, supervised resistance training program.
Habitual protein intake assessed at baseline and adjusted to 1.6 g/kg/day with supplemental protein: soy for VEG, whey for OMN; diet monitored every four weeks.
Before and after: leg lean mass, whole-muscle and muscle-fibre cross-sectional area (CSA), leg-press 1RM.
Registration NCT03907059, retrospectively registered.

Key Results

Both groups improved significantly (all p < 0.05), with no between-group differences (all p > 0.05):

Leg lean mass: VEG 1.2 ± 1.0 kg; OMN 1.2 ± 0.8 kg.
Rectus femoris CSA: VEG 1.0 ± 0.6 cm2; OMN 0.9 ± 0.5 cm2.
Vastus lateralis CSA: VEG 2.2 ± 1.1 cm2; OMN 2.8 ± 1.0 cm2.
Type I fibre CSA: VEG 741 ± 323 µm2; OMN 677 ± 617 µm2.
Type II fibre CSA: VEG 921 ± 458 µm2; OMN 844 ± 638 µm2.
Leg-press 1RM: VEG 97 ± 38 kg; OMN 117 ± 35 kg.

Practical Application

"Can I build muscle on a vegan diet?" In 38 untrained young men over 12 weeks of resistance training, habitual vegans eating ~1.6 g/kg/day of protein (whole foods plus soy isolate) gained the same leg lean mass as omnivores eating the same amount with whey (1.2 kg in both groups), with no difference in strength or fibre size. With enough total protein, the source did not matter here.
The condition is the total: both groups were brought to 1.6 g/kg/day; a vegan diet left at its habitual protein intake was not tested.
Not from this paper; the base's own practice: plant-based athletes aim for the same daily target as everyone else (REF-579, REF-725) and lean on soy or protein blends; why plant protein per gram is weaker acutely is covered by the base's plant-protein review, and daily nutrition by SYNTH-69.

Limitations

Not randomised: groups were habitual vegans and omnivores, so differences in habits beyond diet are possible.
Untrained young men only; 12 weeks; lower-body outcomes.
Plant group used soy isolate; other plant proteins and whole-food-only vegan diets were not tested.
Retrospectively registered.
Written from the abstract and record metadata only (full text not read).
How this entry was checked and changed
Why this level

parallel comparison, n=38 (19 + 19); groups are self-selected by diet, and the trial was retrospectively registered