Rethinking Sustainability in Plant-Based Proteins: A Systems Perspective from Crop to Consumer.

Plant-based protein (PBP) foods are increasingly promoted as sustainable alternatives to animal-derived proteins, yet their environmental and nutritional performance depends on complex interactions among crop selection, agricultural practices, processing technologies, formulation strategies, food safety controls, and climate variability. This review synthesizes evidence across the entire plant-based protein value chain, examining how crop physiology, protein extraction and structuring, ingredient functionality, safety risks, and nutritional outcomes are shaped by both technological choices and environmental changes. Particular attention is given to climate-induced alterations in protein concentration, amino acid composition, mineral bioavailability, and contaminant risk, and how these upstream changes propagate through processing and food formulation to affect consumer health outcomes. We argue that sustainability is an emergent system-level outcome determined by interactions among biological, technological, nutritional, and socio-economic factors rather than an intrinsic property of any given crop or protein source. The review concludes by identifying research, processing, and policy priorities needed to enable scalable, climate-resilient, safe, and nutritionally robust plant-based protein systems.