In The Body Book, which is chock full of advice on health and fitness, Diaz shares her own struggles with her skin, even once trying out wrinkle-zapping Botox.
"I've tried it before, where it was like a little tiny touch of something,” she said. "It changed my face in such a weird way that I was like, 'No, I don't want to be like that' -- I'd rather see my face aging than a face that doesn't belong to me at all."
That means she won't be fighting her wrinkles, at least not with plastic surgery.
"I love it, I don't mind. It's like, 'Guess what this means, I've smiled my whole life,'" she said. "I love life. I'm happy I don't have a problem with that."
But the actress, 41, was not always so comfortable in her own skin, struggling with acne for a long time.
"It was embarrassing, and I did everything I could think of to make it go away,” Diaz said. “I tried to cover it with makeup. I tried to get rid of it with medication: oral, topical, even the harshest prescriptions. Nothing helped for very long.
"It was really challenging to cover them up for the cameras," she continued. "It was awkward and embarrassing and frustrating, and I always felt really bad about myself."