Katharine McPhee in Bathing Suit Says "Happy Earth Day"

Katharine McPhee Foster is celebrating Earth Day, by flaunting her incredibly flat abs in a swimsuit. In the mother-of-one’s latest Instagram post, she puts her fabulous figure on display while posing in the ocean. “Happy (almost) Earth Day! 🌍 I love that each year, this day is meant to remind us that we should all try & do our part to take better care of the planet that generations to come will inhabit. Like our kids! While several environmental causes are important to me, I’m probably the most passionate about ocean conservation,” she wrote. How did the star overcome an eating disorder to become the healthiest and happiest version of herself? Read on to see 9 ways Katharine McPhee stays in shape and the photos that prove they work—and to get beach-ready yourself, don't miss these essential 30 Best-Ever Celebrity Bathing Suit Photos!

1. Her Workouts Combine Running and Strength Training

McPhee works out three or four times a week for hour-long workouts with trainer Simon Carter. "We’ll run and we’ll, like, in the middle of each intersection do, 20 push-ups or 20 jump squats, and then start running again, and go for four or five miles," the actress told Health, per Self, about their sessions. Carter also adds in walking lunges up and down hills during her run.

2. She Doesn’t Weigh Herself

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Katharine, who struggled with an eating disorder in her younger years, avoids stepping on the scale. "I stopped weighing myself and doing calories a long time ago," she told Health.

3. She Eats a Clean, Balanced Diet

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Katharine isn’t super strict with her diets, but eats as healthy as possible because it makes her feel good. “I love clean food; it makes me feel good,” she told Health. “But the idea that you can never eat a burger and French fries [without gaining] weight five days later? I just don’t believe that’s true.”

4. She Cheats

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"If there's somewhere special I wanna go - like for Mastro's butter cake or a pizza with some delicious red wine - I break every rule," she told Health. "I'm gonna have the appetizer, the entree, some of your entree, and dessert, just because I love food."

5. Her Diet Has Gotten More Plant-Based

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Katharine revealed to Health that she was influenced by the documentary, What the Health. She said, “it’s basically gearing everybody to be plant-based and vegan. I could never be vegan; I like milk and yogurt and cheese too much. But I’ve definitely moved more toward the vegetarian route.”

6. Her Diet Is Very Green

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Katharine’s diet is filled with lots of green food. “Well, I love avocado toast. I know it’s super trendy but I love it for breakfast; it just feels so nurturing and wholesome and so good going into my stomach. I put a little bit of truffle oil over the avocado with salt and pepper on delicious whole wheat toast,” she told Health. “I also like big salads, like the ones at Sweetgreen. I love Sweetgreen.” Her favorite combo? “Kale, kale, kale, kale. I love kale. And then garbanzo beans, spicy broccoli, red onion, carrot, feta cheese, cucumbers, and then maybe something crunchy, like almonds. I like to eat a really hearty, full meal that’s rich in fiber with good fat, like an avocado, and proteins.”

7. She Intuitively Eats

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After welcoming her first child, Katharine confessed to Katherine Schwarzenegger Pratt, during her Instagram Live series Before, During and After (BDA), that she struggled a bit with her body image during her pregnancy but was able to get through it. "The way I was able to overcome disordered behavior, in terms of food, was not obsessing and letting my body tell me what was needed," she said. "Not being like, 'It has to be oatmeal in the morning, four ounces of protein,' because that makes me crazy."

8. She Belives “Diets Are the Worst”

In a recent Instagram post, Katharine explained that she lost her baby weight in a healthy way. "I lost this baby weight without dieting. Zero. Diets are the worst and I've had zero pressure from anyone,” she said. "I'll probably gain weight again at some point too. Who cares?"

9. She Takes Zumba Classes

In an Instagram post for World Mental Health Day, Katharine revealed that she loves a certain dancing workout. "More than just a fun workout, Zumba class is a safe space to connect with others, exercise my mental fitness & take my me-time to the next level," she wrote.