Sustainable proteins for future food systems: nutritional quality, environmental trade-offs, and consumer acceptance.

The global food system is under growing strain to deliver sufficient high-quality protein for a rising population, while curbing environmental degradation, tackling climate change, and maintaining long-term food security. Conventional livestock production is a major source of greenhouse gas emissions, excessive land and water use, and biodiversity loss, which has boosted demand for sustainable alternative proteins such as plant-based, microbial, algal, insect, fermented, and cultivated meat products. This multidisciplinary review comprehensively assesses these emerging protein sources across nutrition, environmental performance, and consumer acceptance. It evaluates their amino acid composition, protein digestibility, micronutrient density, and health effects, and quantifies their environmental impacts using life cycle assessment indicators. Noticeable trade-offs in processing intensity, energy consumption, and production scalability are also discussed. Key factors shaping consumer adoption, including sensory traits, cultural perceptions, affordability, and food neophobia, are analyzed. This study further explores technological advances, circular economy strategies, regulatory updates, and policy support for protein transition, identifies critical research gaps, and proposes an integrated multi-dimensional evaluation framework. The findings provide practical guidance for researchers, industrial practitioners, and policymakers to build resilient, equitable, and eco-friendly protein systems benefiting both human and planetary health.