'iCarly' 's Jennette McCurdy on Her Painful Battle with Anorexia and Bulimia: 'I Could Have Died'

For seven years, Jennette McCurdy was the star of the hit series iCarly and its spinoff Sam and Cat, but behind the scenes, the young actress was hiding a painful secret.

"I was a mess for a long time," McCurdy, who battled disordered eating for years, including anorexia, binge eating and bulimia, tells PEOPLE. "But I no longer think about food in an obsessive way. And I once didn't believe that was ever possible."

McCurdy was just 11 years old when she was introduced to restrictive eating by her mother Debbie, whom the actress says abused her physically and mentally.

For more on Jennette McCurdy and other top stories, listen below to our daily podcast PEOPLE Every Day.

"My mom said she could teach me calorie counting and we could be a team, but that I had to keep it secret," says the former actress, whose upcoming memoir details her struggles. "I thought it was an opportunity for my mom and me to be closer."

McCurdy was living on 1,000 calories a day and "sometimes I'd eat even less because I wanted my mom to be proud," she recalls. By the time she was cast as plucky Sam Puckett on iCarly, she had full fledged anorexia.

"Ironically, my character's trademark is that she loves food," says McCurdy. "I'd have scenes where I was supposed to be eating and they'd have a spit bucket. But I'd have terror that there would still be calories left in my body."

McCurdy kept her disorder a secret on set. "I don't think I even realized how intense it was," she says, "but I'm sure everybody just attributed [her weight loss] to normal body fluctuations."

For more on McCurdy, pick up this week's issue of PEOPLE, on newsstands Friday.

Then, when she was 18, McCurdy's mother Debbie was diagnosed with cancer for the second time, and the actress' dangerous habits shifted. "I swung to binge eating," she says. "I would eat everything in sight. I wanted food so much."

Her mother died in 2013. In trying to cope with her death, McCurdy began purging.

"Bulimia took over my life very quickly," she recalls. "I was throwing up up to 10 times a day and I was completely unable to stop. But the cycle of bulimia kept me numb. It was a full-time job, so there was no space to deal with my issues or mourning my mom."

Two wake-up calls pushed McCurdy in the direction of recovery.

"I passed out in my friend [iCarly co-star Miranda Cosgrove]'s bathroom," says McCurdy. "I had been purging and I passed out on the cold marble floor. That terrifies me because I could have died, choking on my own vomit."

The other incident occurred on an airplane bathroom when McCurdy lost a tooth, its enamel worn by stomach acids from purging.

"I realized that destroying myself wasn't going to help anything," says McCurdy. "I needed better tools."

After two years of intensive Dialectical Behavior Therapy, or DBT, McCurdy was able to curb her addictions — and make peace with her mother's death.

"Food was my coping mechanism," she says. Now, "I haven't binged or purged or restricted in years. And I feel very deeply and very strongly about saying I've finally recovered."

If you or someone you know is battling an eating disorder, please contact the National Eating Disorders Association (NEDA) at 1-800-931-2237 or go to NationalEatingDisorders.org.