As of April, casual dining establishments serving sex appeal along with the beer and hot wings can call themselves anything but "breastaurants." That's when Doug Guller trademarked the term for exclusive use at Bikinis Sports Bar & Grill, the company he founded in 2006.

RELATED: BREASTAURANTS TAKE AIM AT HOOTERS

"Breastaurant" describes a dining spot with female servers in revealing outfits. In June, a trade publication, The Nation's Restaurant News, reported that this portion of the casual dining segment had grown to over $2 billion in annual sales.

According to Darren Tristano, executive vice president of the food industry research firm Technomic, 80 percent of the business comes from male customers. "The female servers play a big role in drawing that demographic," he said.

Not everyone approves of the model. Serial entrepreneur and Camping World CEO Marcus Lemonis of CNBC Prime's "The Profit" owns Rose's Café & Bakery, a gluten-free organic restaurant with locations in Evanston and Highland Park, Ill., so he knows a thing or two about running a food service business. In an interview, he opposed using sex to promote one.

"I'm very passionate about steering away from it," he said. "I don't see any value in it long term. How many people can you attract, and what is the risk of offending somebody?"

Whatever the long-term prospects of the breastaurant might be, there's no denying that it's an important piece of the casual dining segment.

This article by Daniel Bukszpan originally appeared at CNBC.com.

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