It all started when Ellen shared a disturbing fact she just learned about Demi's former management team.
"I just learned today that when you came [on the show] for the last six years, the team — you're no longer with this team — there was a team that used to handle everything before you got here."
"They were told to hide the sugar and put everything away so that when you got to your dressing room, even backstage, there was no sugar anywhere near. Did you know that was happening?"
Demi told Ellen that she had no idea her old team was doing that on the Ellen set, but she wasn't surprised to hear it.
"I didn't know that until today, too," Demi responded. "But I lived a life for the past six years that I felt wasn't my own, because I struggled really hard with an eating disorder, yes."
"My life, I just felt, was so — and I hate to use this word, but I felt like it was controlled. By so many people around me."
Demi went on to detail just how closely her team controlled her diet:
If I was in my hotel room at night, they would take the phone out of the hotel room so that I couldn't call room service. Or if there was fruit in my room they would take it out because that's extra sugar. Like, we're not talking about brownies and cookies and candies and stuff like that. It's like, it was fruit.
And, in one heartbreaking anecdote, Demi painfully recalled not being allowed to have cake on her birthday:
And, for many years, I didn't even have a birthday cake. I had a watermelon cake, where you cut your watermelon into the shape of a cake and then you put fat-free whipped cream on top. And that was your cake. And for years I did that, and it kind of became this ongoing joke, but I just really wanted birthday cake.
Fortunately, Demi got rid of that team, and is now focused on practicing self-care and self-love.
"This year, when I turned 27, I have a new team. And Scooter Braun, my manager, gave me the best birthday cake. And I spent it with Ariana Grande, who is one of my good friends, and we just had the best birthday."
"And I just remember crying because I was finally eating cake with a manager that didn't need anything from me, and that loved me for who I am, and supported my journey."
Demi also had a message for anyone who would try to control someone else's diet the way her former team did.
"I think at some point, it becomes dangerous to try to control someone's food when they're in recovery from an eating disorder," she said.
Demi concluded the conversation on a happy note, saying that she's in a much better place now, and sharing a recent moment where she finally felt truly happy after practicing self-care:
It was a Saturday night, and I was like, "You know what? It's a self-care night. I'm gonna take a bath, get a massage." And I just had this moment of happiness after taking care of myself where I started laughing, by myself, in my room.
"And that's why the song that I have coming out is called, 'I Love Me.' Like, we are good by ourselves. We don't need a partner, we don't need substances. We're good."
You can check out Demi's full conversation with Ellen below:
For more information on eating disorders and resources that can help, call the National Eating Disorders Association helpline at 1-800-931-2237; for 24/7 crisis support, text “NEDA” to 741741.