FC Online Marketing, headquartered in Levittown on Long Island, said Costa violated a condition of her contract that she remain in good condition, Newsday reported. The company owns the website Ilovekickboxing.com.
"We hired Tara Costa in 2011 to be a spokesperson," Michael Parrella, the company's chief executive, told Newsday. "She came on at a certain weight. We had a fitness clause. She was in material breach after she gained, in my opinion, about 45 pounds. She was supposed to visit 15 of our franchise locations, but we weren't able to send her anywhere because she gained a lot of weight."
Costa, a Bethpage resident, lost 155 pounds on NBC's show in 2009, finishing third.
Her lawyer, Darren Heitner of Miami, says Costa filed a lawsuit in Florida against FC, also alleging breach of contract. He said the suit will be refiled in New York.
Heitner said Costa has not gained weight.