In the past decade, Greek yogurt has morphed into one of America's most popular breakfast and snack items. In fact, from 2007 to 2012, the production of Greek yogurt in New York state nearly tripled, going from 106,000 to 315,000 tons a year. And for good reason: it's absolutely delicious, full of gut-friendly microbes, and jam-packed with nearly twice the protein found in many other yogurt types. But there's always a downside. Greek yogurt's production process leaves behind literal tons of wasted whey (the liquid part of yogurt). In 2012, New York state produced 315,000 tons of the yogurt and left 630,000 tons of whey behind as waste. But in a paper out this month, researchers say they've figured a way to use bacteria and the otherwise wasted whey to create biofuel and food for livestock.