The Smallest Gainer?

After watching a minute of The Biggest Loser before recovering my senses and turning the television off, a thought occured to me.
Apparently it is prime-time viewing to watch obese people sweat, cry, breakdown, etc in the quest to lose weight.

But what about the other end of the spectrum?
Why is it not prime-time viewing to watch annorexic people cry, breakdown, etc whilst chubby chefs force them to eat food?

I would find that far more entertaining.
One of the reasons being there wont be fat people on my TV screen.