If you've ever played around with one of those carbon or water footprint calculators, you probably know that meat production demands a lot from the environment — a lot of oil, water and land. (Check out the inforgraphic we did on what goes into a hamburger last year for Meat Week.) But have you thought about your meat's phosphorus footprint? Probably not. That's why Geneviève Metson, a doctoral student in natural resource science at McGill University in Canada, did the math for you. She wanted to find out how much of the phosphorus that's mined and turned into supplements for animal feed or fertilizer to grow feed crops goes to the meat industry.