In a recent interview with Variety, the Bad Guy star, who regularly speaks out about animal-rights, was asked: "What's it like being vegan on tour?"
'I never got to eat'
"The first tours we did I used to lose weight because I never got to eat and it was not my choice like it was just we couldn't eat anything almost ever, especially in Europe," Eilish said.
"But now we kinda gain weight when we're on tour cos we have so many people and their whole job is to get us food and make sure we're fed and happy and stuff and going to so many new places...
"It's a really good time to be vegan in life cos' there's a lot of places."
Earlier this year, the celeb announced plans to make her Where Do We Go? world tour 'as green as possible'.
Appearing on The Tonight Show, Eilish told host Jimmy Fallon: "We're actually bringing someone from Reverb, this company that basically specializes in the best and most healthy and greenways to do everything...
"So there are no plastic straws allowed, the fans are going to bring their own water bottles, there's going to be recycle cans everywhere, because it's like, if something's recyclable, it doesn't matter unless there's a recycle bin."