I enjoy the Biggest Loser and Losing It with Jillian, but I always try to keep things in perspective when I watch. I try to focus on the fact that you have people who are beginning to exercise and make "healthy" food choices again (I try not to focus on the "weekly" loss numbers).
The tough thing is that Biggest Loser (and Jillian) have become franchises. In the first season or two, the contestants blogged about what they ate each day/week. You could see how little they were eating (1000-1200 calories a day). Since the introduction/creation of the Biggest Loser plan site, books, videos and Jillian's weight loss DVDs, books and site, this information is no longer provided on-line. Additionally, these details are not provided on the show in any detail. This allows the Biggest Loser to continue growing as a profitable entity. As you all have seen, they receive large dollars for the many product placement "ads" during the show (e.g., Extra gum, Brita water filters, etc.), and not a lot is shown in terms of what/how/when contestants are eating. Additionally, you see the types of exercises that are done, but the details are not provided. This creates a "need" for individuals to purchase their products.
I choose not to purchase the information, but try to enjoy the program for the overall motivation that it provides.
Also, with the prior contestants, they do sign a confidentiality agreement and I know in years passed, the agreement was set for a specific amount of time (e.g., 6 years or something). Once that time passes, they are "free." I'm sure since Kai has shared information (she blogged about this prior to 2010), the contracts have become stronger.