Tori Spelling’s wafer-thin frame has been the topic of much debate — and in her new book, TerriTORI, she reveals why she shed so much weight.

According to USA Today, Spelling, 37, blames swine flu, stomach pain, migraines and nerve problems for her weight loss. She says she had to take three rounds of antibiotics that caused severe stomach pain. “I’ve never had a great stomach, but (being ill) just completely tore up my stomach and broke down my immune system, and I’ve basically just been a mess ever since, stomach-wise,” she says. “It’s about rebuilding my immune system.”

Last year, tabloid rumors got so wild that it prompted the 90210 alum to declare last fall on Twitter that she weighs 107 lbs.

“I’m a role model for a lot of women out there, so I hate that they say these things unwarranted, without any research and facts,” she says. “I think it’s doing a disservice to women out there that look up to any celebrity.”

She says she worries “every single day” how the coverage will affect her daughter Stella, now 2, down the road.

“I’m so grateful that she can’t read yet,” she says. “I’m hoping they’ll let up on that by the time she gets old enough to understand, but I’m going to have to explain to her that this is what happens.”

Spelling — who recently renewed her vows with husband Dean McDermott, as Us Weekly exclusively reported – also weighs in on their marriage, admitting that things got rocky last year.

“We had problems that we never thought we would have,” she vaguely says. “We thought we had the perfect relationship. We realized we love each other, but the communication had completely broken down and a lot of our issues, honestly, came from parenting.”

And how are things with her once-estranged mother, Candy?

“We do talk on the phone. We do e-mail. We see each other for dinners. We do the normal stuff I think families do. There’s no strain,” she says. “We’re still building our relationship, of course, but she’s great with the kids (Stella and Liam, 3). She’s completely involved, which is all I ever wanted. We’re just moving forward.”

From US