Kourtney Kardashian Shares Photo Wearing Kylie's Swimsuit

The oldest of the Kardashian family, Kourtney Kardashian has starred on several reality series, launched her own clothing line, and has dated some of Hollywood’s most high-profile stars. Even after turning 40 and having three kids, Kardashian still stays fit—evident on Instagram, where she shared a photo of herself in sister Kylie Jenner’s Kylie Swim line. Read on to see seven ways Kourtney Kardashian 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 Bikini Photos!

1. She Eats Healthy Snacks

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When Kardashian wants to snack on something, she usually goes for healthy organic treats. She tells WHO Australia that her go-to snacks include, “fresh vegetables with avocado, hummus, raw almonds or a bit of fresh fruit.”

2. She Exercises At Home

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Kardashian doesn’t always need to go to the gym or meet with a trainer to exercise. She finds creative ways to exercise in her home. ​​“I’ll do dips on my bathtub for my triceps. I’ll try to do three sets of 25 a day,” Kardashian says to WHO Australia. “And then, no matter what, I always do 100 squats before I get in the shower because I won’t forget it.”

3. She Exercises Every Day

Even with her busy schedule, Kardashian always tries to squeeze in some exercise. "I think I take time for myself to work out every day, which I never did—especially having three young kids," she told E! News. "I just never made it a priority, and now it just makes me feel so much better—mentally and physically."

4. She Avoids Sugar

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Kardashian tells WHO Australia, that she likes to avoid sugar in her diet. She doesn’t snack on sweets throughout the day, but admits to the website, “After meals it’s important to have something sweet.” She says that her go-to dessert is a matcha chia-seed pudding.

5. She’s A Fan Of Supplements

Kardashian is a fan of taking pre-workout supplements. She tells E! News, "Every morning, when I wake up, I take collagen supplements on an empty stomach.” Kardashian will then drink a glass of water with apple cider vinegar and a vegan probiotic shot. "Both of these habits have a ton of health benefits that affect everything from your skin to the way your body processes nutrients," she says.

6. She Limits Both Gluten & Dairy

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Krdashian told E! News that she limits her gluten and dairy intake for herself and her kids, and she has a good reason to. “We had muscle testing done, which showed we all have sensitivities to corn, gluten and dairy,” she says. "I have noticed a great positive change in behavior with my children when we stick to a gluten-free and dairy-free diet." However, Kardashian does indulge once in a while, “I do let the kids have popcorn at the movies and a churro at Disneyland."

7. She Does Interval HIIT Training

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Kardashian’s trainer, Amanda Lee, revealed the reality star’s workout to Poosh.com. Lee revealed that she and Kardashian do interval training HIIT workouts, which include mountain climbers, jump squats into jump lunges, burpees, and jumping jack planks. “If cardio’s your thing, this is the workout for you,” Lee wrote.