Sonic blends beef and mushrooms for more eco-friendly burger

The popular fast food chain Sonic Drive-In is making a change to the traditional burger -- swapping in mushrooms for some of the meat to make it lower calorie and more environmentally friendly. The chain's new Signature Slingers will contain 25 percent mushrooms, NPR reports. In a news release, Sonic says it "revamped the traditional American cheeseburger" to offer "all the flavor ... with none of the guilt."

The new burger debuted on the menu Monday and starts at under 350 calories. The recipe includes three ingredients, the company says: 100 percent pure beef, mushrooms and seasonings. 

The Signature Slinger "delivers the juicy savory deliciousness you expect from a burger in a way that makes you feel like you're getting away with something," said Scott Uehlein, Sonic's vice president of product innovation and development.

Aside from their promised "deliciousness," the part-mushroom burgers offer an eco-friendly edge.

Reducing the amount of beef will help reduce the amount of greenhouse gasses that are emitted in the production process. Raising beef for the American dinner table does far more damage to the environment than producing pork, poultry, eggs or dairy, according to a 2014 study in the journal Proceedings of the National Academy of Sciences.

Beef produces five times more of the heat-trapping gases per calorie, puts out six times as much water-polluting nitrogen, uses 11 times more water for irrigation and requires 28 times more land, the study found.

"It really looks like beef is a lot worse environmentally than these other meats," said Ken Caldeira, an environmental scientist at the Carnegie Institution for Science.

Richard Waite, of the World Resources Institute, which has been pushing fast food companies to offer more plant-based and sustainable menu options, applauded Sonic's move.

"I think it's great!" he told NPR. 

The Mushroom Council, an industry trade group, partnered with Sonic on the new hybrid burger.