Alternative burgers are on the rise in restaurants, as beef burgers give way to leaner meats and vegetarian choices. Chicken burgers top the list of fastest-growing burgers on menus, rising 23 percent since 2013 on limited-service restaurant menus, according to Technomic.

Burger King recently released its new Flame Grilled Chicken Burger, featuring a chicken burger patty, tomatoes, lettuce, mayonnaise, ketchup, pickles and onions on a brioche-style bun. “We’ve never seen more interest in chicken burgers than we do today, so we’re excited to now offer them to guests everywhere,” said Eric Hirschhorn, chief marketing officer, North America, for Burger King. “Our guests tell us they love the taste of our burgers because we fire grill them over an open flame, so now we’re taking what we do best and applying it to a burger made of chicken.”

McDonald’s also has been testing chicken burgers in the Tampa Bay, Florida area. The burgers feature a quarter-pound ground chicken patty made of a blend of breast and thigh meat. The Classic version offers red onions, lettuce, tomatoes and ranch sauce, while the Signature variety includes grilled onions, lettuce, tomatoes and a “signature” sauce. Both are served on a potato bun.