The 36-year-old fitness fanatic reveals in the new issue of Parade magazine's Healthy Style that she went under the knife to rid her face of a nose that was "the size of a softball" and subjected her to cruel ridicule in middle school.
Michaels, who has admitted many times that she was an overweight child, says she weighed about 175 pounds when she decided to have rhinoplasty to reduce her nose in an attempt to stop the bullying.
She shares a "before" pic with the weekly, revealing a heavier face and a nose that is much more prominent than the one familiar to her television fans.
"Once I was sitting at lunch and got surrounded by a bunch of kids who let me have it about how ugly I was -- my unibrow, the size of my nose, the fat rolling over my jeans. It was pure hell. My mother had to pull me out and enroll me in another school," she tells the mag.
"I had my nose done," Michaels explains. "I felt much better about myself. Plastic surgery is a very personal decision."
The trainer and star of "Loser" spin-off "Losing It With Jillian" did not say when she had the procedure but shared that it was only the beginning of a long process to repair her eroded self-esteem.
The buff workout queen, who is now 5-foot-2 and weighs 120 pounds, has been in therapy since the age of five and still seeks counseling as often as twice a week.
"It's important that I don't end up playing out my own pain and insecurities with the people I'm trying to help," she says.
Meanwhile, read why some Middle Eastern women are opting for "ethnic rhinoplasty" to change their profiles.
And consider these cases of real women who've contemplated plastic surgery in StyleList's regular "Post Your Face" column.