Michael Ventrella

'The Biggest Loser' faces weighty challenge

'The Biggest Loser' faces weighty challenge

Bob Harper isn't going anywhere.

Season 11 of "The Biggest Loser" starts Tuesday on NBC with the biggest twist the weight-loss show has ever seen: Contestants must choose between working out with Harper and Jillian Michaels or with two unknown trainers.

Why would anyone choose the latter? Because it comes with four weeks immunity from elimination — the most valuable prize the show has to offer short of the $250,000 payday awaiting the contestant who loses the largest percentage of his or her body weight.

The introduction of the two new trainers — as yet unnamed, although the blogosphere is already buzzing about their identities — comes shortly after Michaels...