The most famous fast-food restaurants are burger joints: McDonald’s (MCD), Wendy’s (WEN), Burger King (BKW). But Americans have been in the mood for something different lately, and many of the trendiest quick-serve restaurants indulge that desire for variety, novelty and healthier eating.

Like other parts of the lackluster economy, restaurant industry sales have been growing slowly. So new chains hoping to become the next Five Guys or Chipotle (CMG) have garnered attention with standout food, flashy preparation and an eye-catching atmosphere. It also doesn’t hurt, of course, if a meal seems like a bargain.

To identify some of the most promising up-and-coming fast-food chains, Yahoo! Finance teamed with Technomic, a Chicago food-industry research firm that tracks more than 2,000 chains. Technomic sorted its data to highlight firms with annual sales between $3 million and $25 million and more than 10 outlets at the end of 2012. Among those, here are the fastest-growing chains that could open near you before long:

Cups Frozen Yogurt (12 locations in New Jersey and New York, according to the company Web site; 400% annual growth in the number of outlets). The yogurt gets good reviews but the buzz comes from pounding music, a nightclub ambiance and arresting female staffers who have led some customers to dub this chain "the Hooters of froyo." Check the name (and the logo) for double entendre.

Let’s Go Yogurt (29 locations in Florida, New Jersey and Massachusetts; 285% growth rate). It’s not dessert, it’s a “yogurt experience,” with flavors such as Zeusberry Greek and Ooey Gooey Cinnamon Bun. While yogurt may not seem like traditional fast food, it's one of the hottest trends among quick-serve restaurants.

BurgerFi (20 locations in Florida, Georgia and nearly a dozen other states; 250% growth rate). Taking on the established burger chains requires something special, which in this case is “all-natural grass-fed beef” meant to taste like a premium steak on a bun. Veggie burgers are also on the menu. And to convince you that it’s not McDonald’s, BurgerFi also includes furniture made from recycled products in all its stores, along with huge ceiling fans meant to cut down on electricity use.

100 Montaditos (10 locations in south Florida; 233% annual growth rate). This is a popular European chain that offers authentic tapas-sized sandwiches and other Spanish fare. It’s a hit with Hispanics but offers anybody a flavorful alternative when you’re tired of Subway footlongs. Beer and wine goes for as little as $2. Bring on the siesta.