Not wanting to upset her mum, Demi agreed to see a dietitian, but would drink litres of water to make it look like she was putting on weight.
She added: “The dietician made me a meal plan and told me to try to gain at least 1kg a week, or I might have to go into hospital.
“I attempted to eat a little bit more, but I would do anything to fake putting on weight, to avoid hospital.
“An hour before the appointment, I would drink litres and litres of water, so it seemed like I had put on weight.
“I know now how crazy that is, but at the time, it was what I thought I had to do.”