Despite giving birth three times, the Duchess of Cambridge (AKA Kate Middleton) has managed to maintain a lean and toned figure.

While she’s rarely given any insight into her life as a royal, let alone her diet and exercise routine, over the years various sources have dropped hints and info on how the Duchess stays in tip-top shape.

To slim down for her wedding, Kate was rumoured to have followed the Dukan Diet – a high-protein, low-carb program that other A-list celebs such as JLo and model Gisele Bündchen claimed to use to drop their baby weight.

The Dukan Diet involves four stages: attack, cruise, consolidation, and stabilisation. In the ‘attack’ stage you can only eat protein for four to six days. You’re then allowed to introduce some vegetables into your diet during the ‘cruise’ phase. The ‘consolidation’ phase brings back some fruits, carbs, and cheese, along with two cheat meals a week. Then the ‘stabilisation’ phase refers to maintaining a healthy, balanced diet for the rest of your life, while also incorporating the ‘attack’ mode once a week.

It’s also rumoured that Kate’s mother is another fan of the diet, and curbs her cravings with prawns and cottage cheese.

The Duchess suffered from extreme morning sickness while she was pregnant with her first two children, Prince George and Princess Charlotte. She reportedly had to undergo food hypnotherapy to encourage an appetite despite her nausea. The Duchess stuck to a diet rich in avocados, berries and oatmeal to help put on the weight needed for a healthy pregnancy. Kate also suffered with hyperemesis gravidarum – severe nausea, vomiting, weight loss, and electrolyte disturbance during pregnancy – when she was pregnant with her third child, Prince Louis.

When Kate isn’t following the Dukan Diet, it’s been reported that she likes to dabble in the raw food trend at least one day a week, which might be the secret behind her glowing skin and luscious hair. Her raw food favourites include the beloved Latin American dish ceviche, goji berries, watermelon salad, gazpacho, and tabbouleh.

According to Marie Claire UK, the Duchess also enjoys mixing spirulina powder in her morning kale, spinach, lettuce, cilantro, and blueberry juice smoothies. Spirulina, a blue-green algae, is packed full of vitamins, minerals, proteins, and antioxidants. Moreover, it’s known to boost the immune system, fight off infections, and protect against allergic reactions.

Although it sounds like Kate is the walking and breathing definition of health food trends, it’s confirmed she’s definitely not a fan of hipster almond milk.

Volunteers at a charity-run café visited by Prince William and Kate earlier this year, put almond milk on the table especially with the Duchess in mind, but the mum-of-three is said to have told Kim Gardener, who runs Betel UK’s women’s house: "Don't believe everything you read – I don't even like almond milk."

While genetics obviously play a significant role in her lean figure, Kate is known to be “an exercise junkie”, according to a Daily Mail insider. The mum-of-three played sports throughout her childhood and teenage years, and despite her busy schedule now, she makes sure to maintain her fitness levels. On top of being a devoted skier, cross-country runner and hockey player during her schooling years, Kate had a strong passion for tennis – a sport she still regularly plays.

When she’s not running in Norfolk with Charlotte in her buggy and Lupo the dog at her side, the Duchess of Cambridge fits in an hour workout session, warming up with skipping and indoor rowing, followed by interval training where she incorporates exercises like hip raises, squats, calf raises, bridges and push-ups – all without a personal trainer.

After giving birth to her first child Prince George, the Duchess of Cambridge used a popular postnatal program, Busy Mums Fitness, to whip back into shape. Founder of the program, Kelly Rennie, created the program based off her own 20kg weight loss experience.

Although Kate likes to vary her workout routine all the time, she can never do a workout without adding in her all-time her favourite exercise: the plank.

“It tightens her muscles,” a royal insider told Daily Mail. “There are three elements, the basic plank, the side plank and the prone skydive, all of which are positions Kate can hold for 45 seconds or longer and repeat at least ten times each.”

It’s also been reported that Kate employs rowing and cycling exercises into her workouts, and uses a Swiss gym ball to focus on her abs.

The Duchess has also become a fan of Crossfit – a high-intensity fitness program that combines a wide variety of functional movements in a timed workout. She reportedly focuses on a number of different cardio and resistance training exercises to burn excess fat and keep her muscles strong.

When she’s not sweating it out in a rigorous workout, the Duchess is said to enjoy yoga to calm her mind, de-stress, and “keep her supple”. “Seated poses — known as asanas — are a Middleton favourite. Kate enjoys Pilates, too, which has helped her posture since having children,” a source told Daily Mail.