Last year, Beyonce and Jay-Z pledged themselves to veganism in preparation for Coachella. Now, as the world welcomes a new year, the power couple is encouraging fans to do the same. The married rappers wrote an introduction for a new book by Marco Borges, an exercise physiologist and close friend to the Carters, in which they advocated for how important it is to maintain a plant-based diet, according to Billboard.

In the book, called The Greenprint: Plant-Based Diet, Best Body, Better World, the Everything is Love rappers shared how becoming parents gave them a new perspective on what they should eat.

“Having children has changed our lives more than anything else,” they said. “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.”

The couple added that a widespread shift to veganism would have a “profound impact” on the environment, challenging fans to try the diet out as Jay-Z and Beyonce attempt to master it themselves.

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

The couple first discussed going vegan in 2013 as part of their 22Days Challenge, according to NME. Borges encouraged Beyonce and Jay-Z to join the initiative, which focused on a vegan diet for 22 days in an effort to change dietary and exercise habits long term. For years, it has been said that habits can be formed in a minimum of 21 days.

Then, last year, Beyonce revealed in an Instagram post that she was on a vegan diet to prepare for her Coachella performance later in the year.

“44 Days Until Coachella!! Vegan Time!!” she captioned the post.

The couple is among a slew of other celebrities who have devoted themselves to veganism and advocated for the diet. Miley Cyrus, Ariana Grande, Benedict Cumberbatch, and Zac Efron have also gone vegan, Daily Edge reported.

Beyonce and Jay-Z’s message comes just in time for Veganuary, a pledge that many people have taken so far to try veganism for the month of January. Over 250,000 people in 193 countries have reportedly signed up so far to cut animal products from their diets, a record number according to Rich Hardy, head of campaigns at Veganuary.