I have struggled with my reaction to "The Biggest Loser" (along with other TV shows about body size), but my strongest reaction is to the seductive quality of the magical transformation that we see in the contestants. My experience is that changing habits that result in permanent weight loss requires SUSTAINABLE changes in our eating and activity patterns. Fast weight loss is fun to watch on TV, but weight loss that is for keeps requires a very different approach.
"My concern is that such shows not only establish unrealistic expectations but could promote unhealthy, potentially risky, behaviors from viewers attempting to emulate these spectacular results (see Chart at link below). In the article, "Is "The Biggest Loser" Really a Big Winner or Just a Big Loser?" Dr. James Hill of the University of Colorado at Denver states that such entertainment is "...trivializing the complex genetic and environmental influences on our behavior and weight."
http://scienceblogs.com/deanscorner/2010/12/_nbcs_biggest_loser_has.php