Kate Middleton is often praised for her fashion choices, ability to project a certain image as a royal and for being a hands-on mom to her three kids. However, the Duchess of Cambridge does sometimes raise eyebrows due to her slender figure.

It is believed that Middleton is a size six, and according to Express UK, it is likely that the Duchess is able to keep such a slender frame due to her active lifestyle, which has been seen on royal outings where she has also engaged in sports and proven she likes to stay in shape. In addition, the Duchess may still follow the Dukan Diet, a plan she followed ahead of her 2011 wedding to slim down.

The diet consists of three phases, known as the “attack,” (where followers only consume protein for a certain number of days), before introducing vegetables in a “cruise” phase and reintroducing light carbs, fruit and cheese in a “Conciliatory” phase. Middleton reportedly followed it for the wedding and potentially afterward as well.

Middleton has also reportedly dabbled in the raw food diet trend as well, and it’s even been reported in the past that when she has a craving for something sweet, she makes a smoothie of pureed berries and almond milk, which helps curb her cravings but without adding too many calories to her daily intake.

However, while she may simply just be keeping active and eating well, it doesn’t mean that Middleton’s figure hasn’t raised questions in the past.

It has previously been speculated that while she is widely reported to be a size 6, she could actually be closer to a size 2 since photos pf the Duchess likely show her as larger than she is because the camera adds 10 pounds. It especially raised concerns because of Princess Diana’s own history with an eating disorder, though it was revealed by other royal insiders that there likely wasn’t anything to worry about.

“I don’t think we have a problem like Di did with weight,” one insider revealed. “I don’t think William would put up with it, he’s very attuned to things with Kate, unlike how Charles was with Diana.”

Catherine, Duchess of Cambridge
Kate Middleton is pictured arriving at the Cridge Centre for the Family on Oct. 1, 2016 in Victoria, Canada. Getty Images