Is plant-based protein supplementation as effective as whey protein? A systematic review and meta-analysis in untrained adults undergoing resistance training

Background Dietary protein supplements are commonly consumed to support increases in lean body mass among healthy adults engaged in resistance training (RT). Although whey protein has been extensively investigated, plant-based protein supplements have emerged as a viable alternative for individuals who avoid animal-derived products.Methods The present study aims to evaluate, through a systematic review and meta-analysis, the effects of plant-based versus whey protein supplementation on body composition in untrained adults (18–59 years) undergoing RT, using Dual-Energy X-Ray Absorptiometry (DEXA). The systematic review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 checklist and was registered in PROSPERO (CRD420251145410). Searches were conducted in PubMed, Web of Science, and ScienceDirect, identifying 5 studies that met the inclusion criteria for qualitative synthesis and meta-analysis.Results When combined with RT, both plant-based and whey protein supplementation were associated with improvements in lean body mass (LBM) and body fat mass (BFM), with no significant between-group differences observed.Conclusions Thus, soy- and pea-based protein supplements may support favorable body composition changes in adults initiating RT and could be considered practical nutritional options for individuals seeking alternatives to whey protein. Regarding chia-based protein, the available evidence is currently limited to a single study that did not demonstrate significant changes in lean body mass; therefore, firm conclusions regarding its efficacy cannot be drawn at this time.