The reality show has tapped into an American obsession with losing weight, but some doctors not affiliated with "The Biggest Loser" weight loss program question its safety, according to a New York Times article.

Physicians questioned the safety of severe caloric restrictions and up to six-hour workouts resulting in up to 15 pounds lost in a single week on the NBC show, according to the article. Weight loss that is too rapid can lead to severe health problems.

“I’m waiting for the first person to have a heart attack,” Charles Burant, a professor of internal medicine at the University of Michigan Health System and director of the Michigan Metabolomics and Obesity Center told the New York Times.

Burant called the show "exploitative" and counsels his own patients against trying to mimic the rapid weight loss tactics seen on the show.

An executive producer for the series, JD Roth, defended the show's format by saying it "needs to be extreme in my opinion.”

“For some of these people, this is their last chance,” he told the New York Times. “And in a country right now that is wrestling with health care issues and the billions of dollars that are spent on obesity issues per year, in a way what a public service to have a show that inspires people to be healthier.”

The show airs on Tuesday evenings, but will feature a two-hour special "The Biggest Loser: Where are they now?" this evening with contestants from the the previous seven seasons. It starts at 8 p.m.

Tina Reed covers health and the environment for AnnArbor.com. You can reach her at tinareed@annarbor.com, call her at 734-623-2535 or find her on Twitter @TreedinAA.