(CNN)At 14, Ashlee Thomas was in the grips of anorexia.
She weighed 85 pounds. She was hospitalized. Her heart stopped twice. Doctors thought she would not survive.
But she did. And now the resident of New South Wales, Australia, is dedicating her life to helping other girls. Her first warning to parents and children is about the dangers of Instagram, where, Thomas says, her journey to a near death began.
On the app Thomas started following "clean eating" influencers. She was an athlete looking to have the most fit body she could create. And the bodies she considered ideal streamed down her timeline every single day, with every "like" and comment enticing her to emulate the types of bodies she saw.
"I just wanted to be liked and loved like they were," said Thomas, now 20.
"I wanted to get a taste of that."
But the opposite happened. She began to hate herself.
One commenter reacted to photos Thomas posted of herself by writing that her stomach was fat. At some point she stopped eating. She said her parents tried everything to get her to eat. Child welfare authorities were called on them as they resorted to force feeding her.
"It got to the stage where I remember sitting down and my dad holding my jaw open and my mom syringing food into my mouth because I just refused to eat," Thomas recalled.
'There isn't some quick fix to this thing'
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Thomas' struggles are just one example of Instagram's potential "toxic" effect on teen girls, as highlighted in the congressional testimony Tuesday of Facebook whistleblower Frances Haugen.
"I believe Facebook's products harm children, stoke division and weaken our democracy," Haugen, a 37-year-old former Facebook product manager who worked on civic integrity issues at the company, told a Senate subcommittee.
Facebook's own internal research, cited in one of Haugen's filings to the Securities and Exchange Commission, showed "13.5% of teen girls on Instagram say the platform makes thoughts of 'Suicide and Self Injury' worse" and 17% say the platform makes "Eating Issues" such as anorexia worse.
Its research also claimed Facebook's platforms "make body image issues worse for 1 in 3 teen girls." (Instagram is owned by Facebook.)
"The company's leadership knows how to make Facebook and Instagram safer but won't make the necessary changes because they have put their astronomical profits before people," Haugen said during her opening remarks. "Congressional action is needed. They won't solve this crisis without your help."
Facebook CEO Mark Zuckerberg took to the platform he built to defend the company against Haugen's allegations, saying in a 1,300-word statement that the tech giant's research on its impact on children was being misrepresented.
"We care deeply about issues like safety, well-being and mental health," Zuckerberg wrote.
He added, "Many of the claims don't make any sense. If we wanted to ignore research, why would we create an industry-leading research program to understand these important issues in the first place?"
In a statement, Facebook disputed the interpretation of the research and insisted the percentages are much lower. The company has also said it welcomes regulation.
Still, those familiar with the workings of the tech world say it will take much more to save teens.
"Their business model's putting kids into these kinds of loops of engagement," said Tristan Harris, co-founder of the Center for Humane Technology. "And that's what I'm really worried about... that there isn't some quick fix to this thing. It's the intrinsic nature of the product."
Content from extreme dieting accounts can act as validation for users already predisposed to unhealthy behaviors, according to experts.
Pamela Keel, director of the Eating Behaviors Research Clinic at Florida State University, said the posting of photos to Instagram increased concerns about weight and shape as well as preoccupations and dissatisfaction with one's appearance.
"That's actually one of the most robust risk factors for developing an eating disorder," she said.
Instagram's broad reach among young women and girls means that such content posted to its platform can be especially dangerous, according to Keel.
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In video from her family, Thomas is seen screaming and crying when her parents demand that she eat.
"I can't do it," she cried.
"Come on open your mouth and just put it in and swallow," she is told in another video.
"When I was admitted into hospital, the doctor said to me, 'We don't understand why you're here. You should be dead,'" Thomas recalled. "Actually in hospital ... my heart failed twice."
Thomas admits she was "very addicted" to Instagram.
Anastasia Vlasova, an eating disorder survivor who lives in New York and attends New York University Gallatin, said she had a similar experience.
"I was most definitely addicted to Instagram," she said.
Vlasova was lured by the images of women with chiseled bodies and perfect abs. The more toned bodies she saw, the worse she felt about herself, she said.
"I was just bombarded with all of these messages of you have to exercise every single day, or you have to do these types of exercises or you have to go on this type of diet and avoid these foods," she said.
Vlasova, now 18, called it an "unhealthy obsession" that afflicted many young people her age.
Instagram endangered their lives not only by failing to crack down on accounts promoting extreme dieting and eating disorders, but by actively promoting those accounts, according to the young women.
"We shouldn't have to end up in hospital beds or we shouldn't have to be fed by the nose or gastric tube or our parents have to say goodbye to us or hand over their parental rights because your platform is encouraging us to starve ourselves or to eat cleanly," Thomas said.
