This review discusses the future of protein supply and demand, focusing on strategies and factors influencing a sustainable equilibrium. The global population is expected to increase by 50% by 2050, leading to higher demand for food, particularly animal-based protein, which has negative environmental impacts. The paper explores potential demand scenarios and evaluates existing and novel protein sources, considering nutritional, environmental, technological, and market factors. It concludes that existing protein sources, while having environmental and health concerns, offer social and economic benefits and are well-accepted by consumers. Novel proteins require new value chains and attention to production costs, food safety, scalability, and consumer acceptance. The paper also highlights the role of livestock in reducing greenhouse gas emissions and the importance of a sustainable diet for food security. It discusses the potential of plant-based proteins, including pulses, which are important for protein supply and have lower environmental impacts. Insect-based protein is also considered as a sustainable alternative, with lower environmental impacts and high nutritional value. Algae, including microalgae and seaweeds, are promising protein sources with high protein content and potential for sustainable production. The paper emphasizes the need for policy alignment, stakeholder involvement, and technological development to ensure sustainable protein supply and meet future demand.This review discusses the future of protein supply and demand, focusing on strategies and factors influencing a sustainable equilibrium. The global population is expected to increase by 50% by 2050, leading to higher demand for food, particularly animal-based protein, which has negative environmental impacts. The paper explores potential demand scenarios and evaluates existing and novel protein sources, considering nutritional, environmental, technological, and market factors. It concludes that existing protein sources, while having environmental and health concerns, offer social and economic benefits and are well-accepted by consumers. Novel proteins require new value chains and attention to production costs, food safety, scalability, and consumer acceptance. The paper also highlights the role of livestock in reducing greenhouse gas emissions and the importance of a sustainable diet for food security. It discusses the potential of plant-based proteins, including pulses, which are important for protein supply and have lower environmental impacts. Insect-based protein is also considered as a sustainable alternative, with lower environmental impacts and high nutritional value. Algae, including microalgae and seaweeds, are promising protein sources with high protein content and potential for sustainable production. The paper emphasizes the need for policy alignment, stakeholder involvement, and technological development to ensure sustainable protein supply and meet future demand.