In 2013, Beyoncé and Jay-Z embraced a plant-based lifestyle. Now, the famous power couple is challenging people to incorporate more vegan foods into their diets to help make a positive impact on health and the environment, PEOPLE reports.

The superstars penned the introduction for the new book The Greenprint: Plant-Based Diet, Best Body, Better World, which was written by Beyoncé’s trainer, Marco Borges. In the message to readers, the pair talk about how becoming parents influenced their lifestyle changes.

“Having children has changed our lives more than anything else,” wrote the couple, who have three kids. “We used to think of health as a diet—some worked for us, some didn’t. Once we looked at health as the truth, instead of a diet, it became a mission for us to share that truth and lifestyle with as many people as possible.”

While Jay-Z and Beyoncé aren’t advising that folks adopt a totally vegan diet, they’re encouraging everyone to eat more fruits, veggies, whole grains, nuts, seeds and legumes and fewer animal products.

This isn’t the first time Beyoncé has invited fans along her on her vegan journey. In 2018, she called for supporters to join her 22 Days Nutrition challenge—which she cofounded in 2015 with her husband and Borges and made available to followers on social media—as she prepared for her legendary second performance at the Coachella music festival.

“We all have a responsibility to stand up for our health and the health of the planet,” Beyoncé and Jay-Z concluded. “Let’s take this stand together. Let’s spread the truth. Let’s make this mission a movement. Let’s become “the Greenprint.”

Click here to purchase the book.

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