Bella Hadid in Bathing Suit Says "Happy Birthday Sister"

Bella Hadid is celebrating her friend's birthday in her bathing suit. The supermodel shared well wishes to pal Yasmine Diba in one of her latest social media posts, which included photos of the girls in their swimsuits. "2011 til forever. couldn't do this life with out you. happy birthday sister," she captioned the Instagram post. How does the beauty stay so fit? Read on to see 6 of Bella Hadid's top diet and fitness tips for staying 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.

Bella doesn't exercise on an empty stomach. "I count on a smoothie, a juice, or a protein drink 30 minutes before the session. After the session, I eat something full of protein like chicken and wholegrain rice. It's ideal to strengthen the muscle mass and to increase the effects of the session," she told French Vogue.

Bella believes that finding healthy outlets – like riding horses – is great for your body and mind. "My earliest memory of happiness, like I remember just my heart always being with my horses and that was always like my, my first memory ever was just me getting on a horse for the first time," she told ID during a recent interview. 

"I've always had a difficult relationship with food. In high school, my relationship with food came from not having control, but food was the one thing I could control. So I would micromanage and make schedules for food, but it's more important to check what's good for your body and your own biology," Bella confessed toHarper's Bazaar. Her diet is mostly healthy but she does allow herself to indulge. "My favorite go-to snack, I eat pizza, at least once a day. It's always like a go-to cuz it always, you know, it tastes good every time," she added to ID. "There's no bad pizza. Also seaweed snacks randomly. Oh, sour Patch Kids and Rose Champagne if i'm feeling frisky."

Bella loves hitting the mountains for a snowboarding session. She recently shared some photos of herself drinking her energy drink, Kin Euphorics, while on the mountain. According to the University of Rochester, snowboarding, like skiing, is a great cardiovascular workout. "Because they are also weight-bearing exercises, they strengthen your bones as they tone your muscles," they say. "Cardiovascular or aerobic exercises also work to reduce your risk for chronic diseases, and lower blood pressure. They also help you maintain a healthy body weight. Through regular aerobic exercise like skiing and snowboarding, you lower your risk of developing conditions like diabetes and heart disease, having a stroke, and perhaps even getting cancer."

"I always say that first thing in the morning, you have to start your day by staring at the sun. When I was going through a difficult time, I would pull myself out of bed, open the blinds, and then just stare at the sun. But it's so true! And now, I have a sun light and I drink Actual Sunshine, our new Kin flavor, which honestly makes me feel like I'm walking on air," Bella told Harper's Bazaar.