Janet Jackson to write about fat

Janet Jackson will chronicle her yo-yoing weight in a new book, PEOPLE reports.

"I’m writing a book on my journey of weight loss and weight gain," Jackson, 41, told PEOPLE at the Hollywood premier of Tyler Perry's Why Did I Get Married?

"[I'm] really coming from the soul with it, and what I was going through at different times in my life and what possibly brought it about for myself," she says of the yet untitled book. She'll also include in the book what she did "nutrition-wise" to slim down "when she needed to," but warns, "It's different for everyone."