The 24-year-old singer, who made her return to the spotlight on American Music Awards, said she brought the changes in her routine to feel healthy, reported ET online.
"I'm horrible at discipline when it comes to working out. So I've been working with my trainer Amy Rosoff Davis for a year now, and when we started the tour, I really wanted to keep it up. I wanted to be healthy; I wanted to feel good. I just wanted to make sure I was the best I could be for the show and for my fans."
The former Disney star also opened up about her skin, revealing that she would prefer to keep it natural rather than putting on layers of makeup.
"I just can't understand when, and no offense, people have to wear makeup all the time," she said, adding that you "can't really fight" pimples. "Life is life.