Demi Lovato has long been open about her battle with drugs and an eating disorder.

While her latest documentary touched upon living with bulimia, she just got real about the huge toll the disorder took on her body.

Lovato shared a side by side of her at her skinniest and now.

The photo was made by @heartbyheartdemi, a fan account.

She talked about living with bulimia in her documentary "Simply Complicated," saying that she relapsed after her breakup with Wilmer Valderrama. 

"What started the relapse was missing Wilmer. And when I feel lonely my heart feels hungry and I end up binging," she said.

While she was able to successfully abstain from drugs and alcohol for almost six years, her eating disorder still bubbles to the surface.

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“When I was in a relationship with Wilmer I went three years without purging and when we broke up that’s one of the first things I did,” she revealed in the documentary. “The less I have to think about food, the easier it is to go about having a normal life and I don’t want to let anybody down so when I do have moments when I slip up, I feel very ashamed."

Lovato revealed that food was medicine for her at a young age.

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“The food came first, when I was 8 years old and my little sister was born, a lot of the attention was taken off me and onto my little sister,” she said in the documentary. “I had started working at that time and was under a lot of stress so I would bake cookies for my family and I would eat all of them and nobody would have any to eat. That was my first memory of food being that medicine for me.”

Lovato revealed that "food is still the biggest challenge" of her life.

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However, judging by by that powerful side by side photo, she's made a lot of progress.

Hopefully Lovato's story — and knowing that it's still a work-in-progress — will inspire the 4.7 million women and 1.5 million men struggling with bulimia.