as of the early 21st century, it was estimated that four billion people live primarily on a plant-based diet, some because of limits caused by shortages of cropland, freshwater, and energy resources. in europe, consumption of plant-based meat substitutes was 40% of the world market in 2019, with sales forecast to grow by 60% through 2025 due mainly to concerns for health, food security, and animal welfare. in the united states during 2019, the retail market for plant-based foods was growing at eight times the rate of the general retail food market.