Kelly Bensimon is heating up Miami in her bathing suit. The former Real Housewives of New York star and supermodel flaunts her forever young figure in a black swimsuit via her latest Instagram post, taken from the W South Beach. "Last one at the pool is buying," she captioned the sultry black and white snap. How does she manage to make 53 look like 35? Read on to see 7 ways Kelly Bensimon 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!

In her book, I Can Make You Hot!: The Supermodel Diet, Kelly reveals that she lost 50 pounds twice. "When I got pregnant with each daughter, I gained 50 pounds. Most people in my position would really watch their diet and eat crazy foods and exercise like a maniac. For me, having children and being able to bear children was such an incredible luxury. I wanted to be a vessel for them and not exercise and diet while pregnant," she explained to The Washingtonian. "As a result, I gained 50 pounds. Believe me, it wasn't easy [losing weight] and having an ex-husband photographing models all the time. But for me, wanting to take care of myself is a really big part of who I am. I like to say I lost the weight gracefully—when my one daughter was five months old people were asking me, 'Are you still pregnant?' But you know what? I have great, healthy kids, and I'm healthy at 44. I treat my body well, and as a result it looks good."

Kelly loves taking group fitness classes. Two of her favorites? SoulCycle and Y7 yoga, she revealed to Page Six. "If you love riding your bicycle, consider a cycling class. If you have a blast on the dance floor, an aerobics class that includes dance moves would be a good choice. If you're a social person, a gym or health club membership may be a good option for you. If you prefer to exercise alone or you find health clubs intimidating, fitness videos and exercises you can do at home may be best for you," says the Mayo Clinic.

Kelly loves to go for runs, often sharing photos of her workouts on social media. "Running alone," she captioned this Instagram post, flaunting her flat abs in a sports bra and matching leggings. "Running is one of the simplest natural exercises available to us. All we have to do is step into our sneakers and go outside. It is a great way to burn calories. However, running will help with weight loss only if it is a sustainable program — meaning weeks and months," says the Mayo Clinic.

Kelly revealed to The Washingtonian the two moves responsible for her legs-for-miles. "My favorite leg exercises are squats and lunges. They just really tone up the inner and outer thighs and lift the buttocks, as well. When your butt muscles are toned, your legs look leaner," she explained. 

Kelly told The Washingtonian that she avoids two dietary trends. "One is skipping meals and the other is fasting," she said. "Both of those do the same thing—every time you skip a meal or fast, you're jarring your metabolism, which causes you to gain weight."

In her book, Kelly reveals that Sunday is her one cheat day. "I love my mom's Irish soda bread, which she used to make on Sundays after I did well in swim meets. I love the pizza I make with the girls, and guacamole and homemade chips. I love doing anything with my kids, and cooking is a good way for them to learn responsibility and how to take care of themselves, and for us to share and make memories," she added to The Washingtonian.

Kelly prioritizes hydration, but instead of water she fills up on a salty soup. "When you're hydrated, you're less hungry," she told The Washingtonian. "Miso soup has a lot of sodium, but it's hydrating, and it helps with digestion and fills you up quicker. But do you need to have a bowl of soup with every meal? No. Instead, you could have a glass of water without ice in it before you start a meal."