At age 71, Christie Brinkley still feels like an "Uptown Girl."The former Sports Illustrated Swimsuit cover model has written a memoir, "Uptown Girl," which explores her rise to stardom and the pitfalls she faced.During her "FOX & Friends" appearance on Thursday, the star was asked how shes stayed in camera-ready shape over the years. And Brinkley didnt hesitate to share her diet regimen.CHRISTIE BRINKLEY BELIEVES MAGIC DIRT MAY HAVE SAVED HER LIFE IN NEAR-FATAL 1994 HELICOPTER CRASH"First of all, my number one beauty secret is that I have been a vegetarian since I was a little kid," said Brinkley. "And I really, truly believe that if everybody would at least try and be a vegetarian or a vegan Im currently a vegan. I have been for the past, maybe a year now.""So try it," she encouraged viewers. "Youll love it. And youll never feel better. And youll be helping our planet, which is vitally important right now."The model previously told Fox News Digital shes a big fan of the "rainbow diet," or "brightly colored foods" rich in vitamins and minerals.WATCH: CHRISTIE BRINKLEY OPENS UP IN NEW MEMOIR UPTOWN GIRL"It fortifies my body and you really, truly are what you eat," she shared. "I treat myself to good nutrition, and I never feel like Im denying myself.""Its no longer called a diet," Brinkley stressed. "Theres no denying myself anything Ive always said, the more you learn about food, vitamins, minerals and exercise and what it does to your body chemistry, the more you will reach for the good stuff because youll want to fuel your body. And thats what I do."Back in her early modeling years, Brinkley was put on an all-fish diet to shed pounds quickly before a photoshoot. These days, Brinkley said she refuses to deny herself the foods she loves. Moderation is key, she said."If I happen to be on some trip, or its somebodys birthday, you have to have a piece of cake because its not good luck to not take a bite of the birthday cake," she chuckled. "I do that, and then I say, Thats fine. Im not going to beat myself up over it. Ill just watch the sugar intake the rest of the day, but I just want to treat my body right.""I've been a lifelong vegetarian," said Brinkley. "But about a year ago, I became a vegan, and I am really, really thrilled that I did, because I have never felt better. I eat lots of grains and beans and all kinds of colorful foods."When asked for a piece of advice she would give her younger self, she quoted her ex-husband Billy Joels song, "Vienna."CLICK HERE TO SIGN UP FOR THE ENTERTAINMENT NEWSLETTER"Slow down, you crazy child, youre so ambitious for a juvenile," she sang. "But seriously, slow down. Enjoy it all. Savor it all. But live."Back in 2021, Brinkley told Fox News Digital she wont step on a scale to manage her weight. Instead, she lets her clothes do the talking."I dont step on a scale," she said at the time. "I have my Honest Jeans tell me the truth. Ill try those on to see where Im at. If I fit into those, I feel good. And when theyre too tight, its OK, too.""At first, I was a little surprised because Ive been wearing a lot of sweatpants," she added. But for me, its smaller portions and a little more exercise. And I choose to focus on counting my blessings, because once you start realizing all the things in your life that youre grateful for, it becomes no big whoop."In 2019, Brinkley told Fox News Digital that keeping her body moving has been essential over the years."Ive always loved sports and doing things outdoors," she said. "Whether its running around the tennis court, stand-up paddleboarding, skiing, kayaking, cycling, mountain trails I just love being active and doing things."LIKE WHAT YOURE READING? CLICK HERE FOR MORE ENTERTAINMENT NEWS"Its just so important to keep moving every day, especially at my age now," Brinkley continued. "My enemy is sitting. Its a big mistake for people to think they need to sit it out. Thats the worst thing you can do. You gotta get yourself to a physical therapist, figure out whats causing those aches and pains, strengthen your muscles and keep going."