A teenager nearly died from cardiac arrest after her weight dropped dangerously low. She says she cut what she ate after following food bloggers on Instagram.
Izzie Tidswell says she slowly reduced what she ate until she became so ill she needed urgent medical care.
Izzie has had an eating disorder for four years. She says following food bloggers on Instagram made her anorexia worse.
It was only when she was in hospital that her dad, Richard, realised just how ill she really was.
"I remember sitting in a room with the lead medical professional turning round to me and saying 'I need to tell you your daughter's at risk of heart failure'", he says.
"That's the thing really, within the space of months you go from someone who is highflying at school, to hearing that and being rushed in for emergency ECGs, that will live with me forever."
And Izzie's not alone.
Sam Woodfield became underweight after over exercising and cutting food. He says he was inspired by food bloggers and lean athletes on the social media platform - he may never be able to have children.
Even though Sam is now recovering, at 28 he still has the bone density of 60 year old - and there are long lasting effects from being so underweight.
"There is a possibility I might never be able to have children, because I really did plummet my hormones that low, they might never rebound."
Health professionals say the true effect of social media is only just being realised - and what is a fun pastime for most, can be a dangerous obsession for others.
Renee McGregor, and eating disorder dietician says social media is holding people in the grips of the mental illness for longer.
She says: "Ten years ago if I was working with somebody with an eating disorder it was a bit easier to move them on because you weren't really up against social media.
"Whereas now when you're working with an individual, you'll make a suggestion, you'll rationalise an argument that they might bring forward, but then literally the following week you see them it'll be 'but such and such is doing this on social media, and they feel great so...'
"I know for a fact there are a number of high profile bloggers who put pictures up but don't actually eat what they've put up."
Instagram says eating disorders are a complex issue and it's working with mental health charities to better understand them.
It adds it provides advice and links to experts, and some of its users promote positive body image and provide support networks for those with eating disorders.
- WATCH IN FULL: An Unhealthy Obsession