The investors, which include the fund arm of insurer Aviva and several Swedish state pension funds, wrote to the food companies on Sept 23 urging them to respond to the "material" risks of industrial farming and to diversify into plant-based sources of protein. Among the companies targeted were Kraft Heinz, Nestle, Unilever, Tesco and Walmart, a statement by the Farm Animal Investment Risk & Return Initiative, which organized the investor group, said on Monday. "The world's over reliance on factory farmed livestock to feed the growing global demand for protein is a recipe for a financial, social and environmental crisis," said Jeremy Coller, founder of the FAIRR initiative and chief investment officer at private equity company Coller Capital. Pollution from intensive livestock production is already at too high a level, while safety and welfare standards are too low and the industry cannot cope with the projected increase in global protein demand, Coller said. "Investors want to know if major food companies have a strategy to avoid this protein bubble and to profit from a plant-based protein market set to grow by 8.4 percent annually over the next five years," Coller said. The campaign follows an Oxford University study which said $1.5 trillion in healthcare and climate change-related costs could be saved by 2050 if people reduced their reliance on meat in their diet. "Forward-looking companies can move now to encourage more sustainable diets by reducing reliance on meat and growing the market for plant-based protein alternatives. In the process, companies make their own protein supply chains more resilient to future shocks," she said. The other companies written to by FAIRR were General Mills, Mondelez International, Ahold-Delhaize, The Co-operative Group, Costco Wholesale Corporation, Kroger Company, Marks & Spencer, Wm Morrison Supermarkets, Ocado, Sainsbury's and Whole Foods Market.