Books and broccoli are Caroline Wozniacki's allies when she's traveling on the Tour.

Wozniacki visited the Dr. Oz Show on Monday to discuss health, nutrition and fitness. After rallying with Dr. Oz while wearing high heels — "I don't want to roll an ankle here," Wozniacki said at one point — the former No. 1 touched on a variety of topics.

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Caro discussed her friendship with Serena Williams, revealing the advice Serena gave after her split from fiance Rory McIlroy last year.

"She's a great friend; we have so many things in common," Wozniacki told Dr. Oz. "I was going through a few personal things last year and she was there for me. We sing karaoke, we talk design, we do all kinds of fun stuff. She said, 'Just keep going. It's not going to be easy always, but it's going to be worth it in the end. At the end of the day, everything's meant to happen that happens for a reason, you're going to come out stronger.' She was right."

The two-time US Open finalist said chocolate is her favorite guilty pleasure ("I love any chocolate," she said) and named broccoli her favorite healthy food.

"I tried it once when my mom made stir fry and vegetables and since then I eat broccoli every day," Wozniacki said. 

Wozniacki de-stresses from the pressures of competitive tennis with books and Bruno, her dog.

"I read books or watch movies. It's the best way for me to relax and get into my own little world," Wozniacki said. "Bruno is my dog. He's always happy and always hungry, which I am too, he's always in high spirits."

Caro's complete appearance on the Dr. Oz Show is here.