"I don't ever feel like I've been particularly wholesome, just relatable. You know, and no one really is wholesome," she said. "I'm a bit of a prude. ... I think it's probably because of all of the stuff I did in my 20s. Now I'm, you know, rebelling against my 20s. "
Bertinelli talked openly about her cocaine abuse, her infidelity, and the messy break-up of her marriage to rock star Eddie Van Halen. She said her tailspin of depression was intertwined with her lifelong addiction to food.
"That's my drug," she said. "That's why I'm still not using coke. I mean I could still be on coke right now but that wasn't my love. Food is my love. I was getting bigger and bigger the tougher it got. That's how I was feeding my fears and calming my emotions, was through food. And it showed."
As for Osmond, food was also an issue at an early age.
She said she remembers producers on the "Donny and Marie Show" "taking me out in parking lots and saying if you don't lose 10 pounds, you are going to be an embarrassment to this family, we are going to cancel the [show]. I mean I was 15 years old, 110 pounds. ... I was thin, and I went down to 93 pounds, which was stupid."
In later years Osmond struggled with severe post-partum depression, a troubled marriage that also ended in divorce. One of her sons entered rehab. She said it was only after her mother died of heart disease that she decided to do something about her weight.
"On her death bed she said, 'Don't do what I did. Don't do it," she remembered her mother telling her. "Don't put the weight on; don't not take care of your health. Don't put yourself last."
Around the same time, Bertinelli got a phone call from Jenny Craig.
Bertinelli cringed at the memory. She said her first thought was, "Oh God, they know I'm fat too! How do they know?"
"My life felt out of control. ... At that point you are just looking for a life raft, a life preserver, somebody help me, and they were there," she said.
"She had been on the radar for a while," Jenny Craig CEO Patti Larchet said. "I think everybody knows who Valerie is. She's the kind of woman, she's very genuine. You think, 'I could be her friend.' I think that's why she's resonating."
Jenny Craig, headquartered in Carlsbad, Calif., has cracked the code on how to find the ultimate weight loss star.
"I think one of the reasons we've been using celebrities for so many years is celebrities create an interest," Larchet said. "So I think the magic kind of, if you will, of rotating in celebrities telling their story is people like reality television."
According to the company, 150,000 people sign up each week, inspired, over the years, by the likes of Monica Lewinsky and Regis Philbin -- and now Bertinelli.
"We have over 84 different foods at any one given time," said Larchet, who climbed the ranks in the company partly on her ability to recruit the right stars. "Our revenues have been going up year after year. Last year was our best year in our 25-year history, but as important -- our clients are losing more weight and staying longer with the program."
Celebrity endorsers can get paid up to an estimated $1 million to lose the weight -- a small price for all the publicity generated for the company. But Larchet said the relationship between celebrities and the diet business is mutually beneficial.