Cameron Diaz's stay-healthy tips

The image we all have of Cameron Diaz is Hollywood's fittest, coolest, most glamorous goofball. So it's hard to believe she didn't uncover her muscles—not to mention that awesome sense of strength and confidence—until she was in her mid-20s.

"I fell into fitness by accident," said the actress, a former string bean and smoker. "But it's become something I depend on physically and emotionally. I feel so much more empowered now."

Hoping to help other women change their lives in the same way, Diaz, 41, decided to write The Body Book and delve into the science behind why she looks and feels so amazing—and, of course, how you can, too.

You write that, during high school, you'd eat two Taco Bell bean burritos every single day.

"I saw a Taco Bell yesterday—it made my stomach scream. If I had nothing else to do, I would be, like, 'Three bean-and-cheese burritos and give me some nachos with extra cheese sauce!' I would so kill that s---. But what I've learned is that just 'cause you can chew it and swallow it and poop it out doesn't mean it's food."

The Body Book is filled with similar lessons—it's like Health 101. Why take that approach?

"I love the science of the body, and I love to give information and see people utilize it in their own lives. I want women to know that it's never too late to start paying attention to their bodies. Until I started training at 27 for Charlie's Angels, I didn't. I literally quit smoking a month before. I was, like, 'Ugh, I've got to do this training. I guess I should stop smoking now.' We trained eight hours a day, seven days a week for three months, and I was dying. Crying every day. On Monday, I wondered how am I ever going to do this, but soon enough, I had a six-pack. At 27, I wasn't consciously saying, 'I'm doing this for when I'm 41.' But at 41, I'm saying, 'Thank God I started at 27.'"

Compared with how fit you've been during different points in your life, where are you now?

"I'm definitely not in the best shape of my life. I had a couple of hernias fixed last summer, so I took six weeks off to rest and heal—and see what happens if I have a liter of olive oil a week. It was sort of an experiment [Laughs]. If I wasn't cooking, I was eating. It was amazing! I put weight on and loved it. But as soon as I went back to my normal workout and eating, I dropped it. I was, like, Where's my booty?"

So what's a normal workout?

"At the gym, I'll do intervals on the treadmill for 5 minutes, jamming out for 30 seconds at 10 or 12 mph, then resting for 15 seconds. Then I do lunges with rows, squats, and pushing and pulling cables. I use 10- to 15-pound weights if I want to build muscle or 5- to 8-pound weights if I'm maintaining; you have to figure out your own needs and fitness level. I do two sets of 15 reps on everything. The whole thing takes me 20 to 30 minutes."

When do you fit it in?

"I do it first thing in the morning. My gym opens at 5:30 a.m., and if I have an earlier call time, I'll just do a quick run, then two sets of 25 dips, step-ups and push-ups. I think it's important to get a workout in, even if you only have 15 minutes."

What about when you don't feel like exercising?

"Some days I don't. Some days I stay in bed because sleep is more important to me at that moment. And some days I go to the gym for literally 10 minutes. But the fact that I got up and got there matters to me. Because at the end of all of this, I want to be able to say, 'I did the best I could.' It's not about having a ripped stomach. It's about taking care of myself. If you don't have your health and if you're not in a strong, capable body, you don't have anything."

You have so many long and strong female friendships. Gwyneth, Drew...

"Oh, I'm still friends with my boyfriends, too. I feel like all my relationships are strong—friends, family. I've invested in my people and they're invested in me."

What would you want to tell the women coming up behind you in Hollywood?

"If the tabloids were what they are now when I was 22, I would not have a career."

Because they would discover all of your secrets?

"Hella f---ing yeah! What I did wasn't seen, and it will not be known. Every 22-year-old does something stupid, and no one needs to see that. It's part of growing up and part of understanding who you are. You do really stupid s---. These young girls are all going to make ridiculous fools of themselves, and who cares what other people think? But at the same time, they shouldn't play into it or do it to spite people. That's the worst high school mentality. 'F--- you, I'm gonna do it because you don't want me to!' You can't win on the scale of the world against you."

What do you see for the future?

"Nothing. I don't look forward like that. I never have. Look back at my very first big press junket for a movie, and in one interview I was asked, 'Where do you see yourself in 10 years?' And I said, 'I don't know. Happy, hopefully.'"