I worked a few seasons on The Biggest Loser. Saw Jillian on a daily basis for months at a time. Cool chick. I liked her vibe a lot. All the "fatties" were under constant medical care, doctors, physical trainers, DC's, etc. She got the best out of them. Some phenomenal results.
I interacted with her and the fatties for 10-12 hours per day, 5 days a week. She knows her stuff. And yes, the show has made her a millionaire.