Is "Biggest Loser" winner Rachel Frederickson too thin?

When 24 year old Rachel Frederickson revealed her body after dropping a whopping 155 pounds (70 kg) from her 5'5" frame, the world collectively gasped. Her transformation, which visibly shocked the shows judges, triggered a heated debate about how much is too much when it comes to weight loss. At the beginning of the competition she weighed 260 pounds (117 kg), losing nearly 60% of her body weight to walk away the winner.

The Biggest Loser, in its 10th year, is shot over a 7 month period and pits overweight contestants against each other in the reality show. At the beginning of each season, contestants are grouped into various teams, each working with a celebrity trainer who tailors nutrition and exercise programs for each player. Along the way, the weight-loss hopefuls are faced with challenges that tempt their willpower. The person with the steeliest resolve who drops the most weight is dubbed "The Biggest Loser" and awarded a $250,000 (ksh. 21,750,000) grand prize.