Vegan and Omnivorous High Protein Diets Support Comparable Daily Myofibrillar Protein Synthesis Rates and Skeletal Muscle Hypertrophy in Young Adults.
Level 2 - randomized trial
Controlled clinical trial with acute metabolic tracer and 10-week longitudinal training phases
PubMed 36822394 · doi:10.1016/j.tjnut.2023.02.023
What was done
Healthy young adults were studied across two phases comparing omnivorous (OMNI) to non-animal-derived/vegan (VEG; mycoprotein-rich) high-protein diets during resistance exercise. In Phase 1, 16 participants (8 OMNI, 8 VEG; protein 1.8 g·kg bm⁻¹·d⁻¹) completed a 3-day dietary intervention with unilateral leg resistance exercise; daily myofibrillar protein synthesis (MyoPS) was assessed via deuterium oxide. In Phase 2, 22 participants (12 OMNI, 10 VEG; protein ~2 g·kg bm⁻¹·d⁻¹) completed a 10-week, 5 d/wk resistance training program. Outcomes included muscle fiber cross-sectional area (CSA), lean mass (DXA), thigh muscle volume (MRI), and muscle strength.
What was found
In Phase 1, daily MyoPS rates were ~12% higher in exercised than rested legs (OMNI1: 2.46 ± 0.27%·d⁻¹ vs 2.20 ± 0.33%·d⁻¹; VEG1: 2.62 ± 0.56%·d⁻¹ vs 2.36 ± 0.53%·d⁻¹; P < 0.001) with no difference between dietary groups (P > 0.05). In Phase 2, 10-week resistance training comparably increased lean mass (OMNI2: 2.6 ± 1.1 kg, VEG2: 3.1 ± 2.5 kg; P > 0.05), thigh muscle volume (OMNI2: 8.3 ± 3.6%, VEG2: 8.3 ± 4.1%; P > 0.05), and muscle fiber CSA (OMNI2: 33 ± 24%, VEG2: 32 ± 48%; P > 0.05). Both groups achieved comparable increases in 1-repetition maximum strength.
Why it matters
When total daily protein intake is high (~1.8–2.0 g/kg/day), a non-animal-derived diet supports daily muscle protein synthesis and resistance-training-induced skeletal muscle hypertrophy to the same extent as an omnivorous diet in healthy young adults.
Limits
Sample sizes were small across both phases (Phase 1 n = 16; Phase 2 n = 22). The study was conducted solely in young, healthy adults with normal BMI, limiting generalizability to older adults or clinical cohorts. The vegan intervention was specifically rich in mycoprotein, so results may not generalize to diets relying on lower-quality or unvaried plant protein sources.
Cited by
- supports Clinical trials by Hamilton Roschel and Alistair Monteyne comparing vegan and omnivorous diets at 1.6 to 2.0 g/kg protein intake showed no difference in muscle hypertrophy or strength gains over 10 to 12 weeks of resistance training.