. >> jenny mccarthy used weight watchers. >> jenny mccarthy came to us after she lost the weight. we had no idea she was doing the program. she came to us after she lost all her baby weight. 60, 70 pounds. >> reporter: bob garfield spent 25 years in the ad business. not that he's cynical. >> you take a "b" list celebrity. who is famously chubby and put them on a crash diet, photograph them before and after, voila, you have a marketing campaign. once again, results, not typical. >> i lost 40 pounds and i gained confidence. >> reporter: the dramatic reveals are turned into television spots that can mean a big bump in business for these companies. >> i think one of the reasons we're using celebrities for so many year, celebrities create interest. the magic, if you will, rotating in celebrities, telling their story, is people like reality television. >> valerie bertinelli made a big splash of the "people" magazine. had to boost jenny craig's fortunes. >> reporter: valerie lost 50 pound on jenny craig. >> i love the program. love the food. >> i'm marine osmond and lost 45 pounds on kne