Since she first entered treatment for bulimia, self-harm, drug use and to help deal with her bi-polar disorder, Demi Lovato has been beyond open about her recovery, inspiring her Lovatics to "stay strong" and not be ashamed of their own issues. However, while we've heard about the 'X Factor' judge's issues and that she's going through a recovery process and rehab, we never really knew everything that entailed -- until now.

In a preview of her interview with Katie Couric on an eating disorder-themed episode of 'Katie,' Lovato reveals what rehab life was like and just how difficult it was to adjust to it.

“I wanted to be very thin," Lovato, who was being treated for bulimia, said. "Treatment was so difficult at first. I remember walking around saying, ‘I’m in prison!’ They needed to have those strict rules in order for me to understand how sick I was. I wasn’t allowed to use the bathroom by myself. We had specific phone times. There are tons of things you weren’t allowed to have, you weren’t allowed to have certain hair products or whatever, that you could injure yourself with or possibly drink, and you were just stripped of a lot of things.”

Not only couldn't Lovato use the restroom alone, but her eating was also closely monitored. “I also had somebody watching over me every single time I ate," she said. "And if I didn’t finish what was on my plate -- and often times I would cry because I physically couldn’t stomach it -- and if that happened, I would have to have little consequences, nothing horrible, just not being able to go to the cafeteria to eat.”

Needless to say, we're happy that those little consequences worked, because Demz is one of our faves! Her full interview will air this Monday, Sept. 24.