During rehearsals for her cheerleader-themed performance with pro partner Sasha Farber, the reality TV star said that, in high school, she would go days without eating.
Polizzi fought back tears as she recalled her struggles with anorexia.
"Cheerleading was my life in high school, but it wasn't always easy for me," she said. "I started to be anorexic.
"I started eating one salad a day, and then it became, like, one cracker a day, and then it became just one grape a day. And then ... just not eating at all for three days."
"It was a really, really bad time for me."
Polizzi said she intends to create "positive new memories" on "Dancing With the Stars."
This was not the first time she has spoken out about her struggle with food. Polizzi has been candid about her 50-pound weight loss since the birth of her 1-year-old son, Lorenzo.
Last month, she revealed she was at her heaviest weight — 146 pounds — during her "Jersey Shore" days. She now weighs 96 pounds and insists that her size 0 physique is "normal." Polizzi credits her new figure to strength training and cardio with her trainer.