24 Hour Fitness Worldwide, the world’s largest privately owned and operated fitness center chain, began as a one-club operation in 1983.   The 385+-club chain made its debut on reality television in 2004.    24 Hour Fitness worked closely with NBC on their new reality show, “The Biggest Loser,” which featured 12 overweight contestants competing to lose weight over several months.   For the past three seasons, 24 Hour Fitness has built an onsite gym, including all state-of-the-art equipment, at the ranch where contestants live while competing on the program.   The show continues to showcase 24 Hour Fitness' mission to make fitness a way of life for everyone, no matter what their fitness ability.