'Marcia Brady' Opens Up About Bulimia Battle

April 5, 2007 — -- For six years starting in 1969, Maureen McCormick was America's favorite big sister on the country's favorite family TV show.

With her long blond hair and miniskirts, Marcia Brady was the oldest, prettiest and most popular Brady sister.

But for years after "The Brady Bunch," McCormick lived with some dark secrets: a decade-long battle with bulimia and, as she revealed to People magazine, a cocaine addiction that lasted six years.

McCormick says she has beaten back those demons and will appear on the latest season of VH-1's reality show "Celebrity Fit Club" to try to lose weight the healthy way.

McCormick, looking fit and younger than her 50 years, said today on "Good Morning America" that she became bulimic after the show ended in 1974.

She was tutored on the set while the show ran, but then went back to high school, where she succumbed to pressure from other girls to try bingeing and purging.

"When I went back to public school, I was with some girlfriends and they said, 'Hey, you know what you can do? You can eat a lot of food and get rid of it.' That's how [I] got into it," she said.

From Humiliation to Happiness on Reality Show

McCormick never told anyone about her eating disorder until recently, when she was asked about it on "Entertainment Tonight."

"It's so weird. I've always wanted to [tell someone]," she said, "but I've never been asked the question, 'Have you ever had an eating disorder?' And they did ask me and I couldn't lie."

Now McCormick is glad that she revealed her struggle with bulimia, because she has a 17-year-old daughter and hopes she can help other girls who struggle with body image.

McCormick told People that she got into cocaine "through a boyfriend, who was friends with people who did drugs."

After six years, she said she kicked that habit as well, thanks to therapy and faith in a "higher power."

McCormick maintained a stable weight for years, until 2004, when her mother died of cancer. Shortly after, she was faced with putting her mentally disabled brother into a group home.

"It was just one of the most difficult things I've ever had to deal with," she told "Good Morning America." "And I still feel a lot of guilt, but I know that he's in a really good place."

Facing those troubles, McCormick said she began to put on weight, and quickly gained about 35 pounds.

The 5-foot-3-inch actress weighed 150 pounds when she got the offer from "Celebrity Fit Club" to join the show.

"I was really kind of humiliated," she said, but it also a "real wake-up call."

Her daughter, Natalie, also encouraged her to join the show. McCormick can't reveal how much weight she lost on the show, but she says the experience was a huge success.

"I feel like I'm really me for the first time," she said. "I feel like I shed weight and other things, the healthy way."