Sadly..this is a 'guilty pleasure' I guess of mine... lol. Unlike you, when I saw the commercials, I thought the premise behind it was...well pretty stupid. But turned to it once when nothing else was really on, and couldn't help but keep watching. The show actually is, in an odd way interesting.
Although, like you said, it probaly should be more about keeping it off, rather then what you lose that week, because...that's really not that hard. For wrestling, if I wanted to I could gain 10 lbs in a day, or lose 10 lbs in a day to make weight...but fact is, in a day or two I'd be back to my set weight.