Kate Upton, the world-famous model and actor, is known for being one of the most stunning women on the planet, her beauty earning her three covers of the Sports Illustrated Swimsuit Issue and a Vanity Fair cover to boot. A mother of one and the wife of baseball player Justin Verlander, Upton rarely posts photos of her in swimwear, but just posted a stunning new bathing suit photo of herself lounging in an outdoor pool. She captioned the post, "Mentally I'm here." How does she stay so fit? Read on to see 5 ways Kate Upton 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!

One of Upton's personal trainers, David Kirsch, disclosed some of the model's diet and exercise secrets to ELLE. Kirsch says that when it comes to Upton's diet, she cuts out a few major foods, and is inspired by a gluten-free diet. "It's sugar, alcohol, and processed carbs that we avoid. I don't have her on a specifically gluten-free diet, but by the nature of what she eats, it is gluten free."

Kirsch also broke down Upton's fitness routine to ELLE. "We do extreme, intense circuit training," he said. "We do three or four circuits and change them up a lot. There's lots of core, butt, and thigh shaping and toning. We work with resistance bands, stability balls, do lateral lunges for the inner thighs, and for arms we do boxing. She has her own pair of boxing gloves, and she will beat me up. She loves it! It's a very efficient way to work out and get your cardio in."

While it may seem like Upton has the perfect body and weight, she says that she doesn't exercise to get to a certain number on the scale. In fact, she told Yahoo Style, that she doesn't even own a scale, and sets goals to where she is happy with her body. "I'm not trying to be fit for a number on a scale," she says. "Whenever I'm happiest, I try to maintain that. I don't need a number."

Upton's other trainer, Ben Bruno, gushed over the model in an interview with E! News. He praised Upton's work ethic and persistence. "Her progress has been amazing. She trains harder than just about any client I've ever had. I've trained a lot of athletes and Kate trains as hard as anybody. She's very dedicated, works hard and the other part too that kind of goes hand in hand with what we do in the gym is that she's got her eating on track. She's very disciplined with her eating. She's been great about limiting sugar."

Bruno said that while Upton eats healthy, she isn't afraid to indulge once in a while. He says that she does enjoy herself at times, but always goes back to eating healthy. "She eats very well most of the time. Sometimes she splurges and when she does she just picks back up and keeps going. She eats treats but it's just about moderation…I don't want people thinking it's a diet. I want them to think it's a lifestyle."