Macro partitioning
Long-term supplementation with plant-based protein (PBP) yields equivalent results to animal-based protein (ABP) for lean body mass, muscle strength, physical performance, and cardiometabolic risk factors in adults.
If you are consuming enough protein daily (typically 1.6g/kg or more for muscle gain), the source (plant vs. animal) matters less than you might think for long-term results. You can effectively build muscle and maintain metabolic health with plant-based proteins like soy, provided you stick with it for at least 6 months.
Long-term supplementation of PBP (largely soy protein) did not show statistically significant differences in lean body mass (LBM), fat mass (FM), total body mass (TBM), upper and lower muscle strength, gait speed (GS), chair stand test (CST), timed up and go (TUG) test, short physical performance battery (SPPB), lipid profiles, blood pressure, fasting blood glucose (FBG), fasting blood insulin (FBI), and homeostatic model assessment (HOMA-IR) for insulin resistance compared with ABP.
Why this rating
High-quality evidence from a systematic review and meta-analysis of 18 RCTs, though heterogeneity was significant.
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
Mohammed Ahmed Yimam et al. · Frontiers in Nutrition · 2026
This is one finding among thousands. Every one is graded and traced to its source, so you can see what the evidence actually supports. Browse the research →