Sam and Charlotte are twins. They have always been close and grew up sharing secrets and having a laugh together.
But when they were 12, Sam developed the eating disorder anorexia and their relationship changed.
As Sam's world became focussed on food and how she could avoid eating, Charlotte worried about how she could help her sister recover.
It started when people told Sam how good she looked after losing weight from being ill at Christmas.
"I thought that if I carried on I would lose more weight and it just got out of control," she said.
"I was in a class with very slim girls and I always felt like the odd one out. I just wanted to fit in."
'I'm not hungry'
But Charlotte soon noticed Sam wasn't eating at school.
"I just remember one day I said 'Aren't you having anything?' and she said 'I'm not hungry'. But Sam never said that because she used to love her food."
As the anorexia took hold, Sam became increasingly quiet and withdrawn but it wasn't until Charlotte saw her getting changed at home that she realised how much weight she'd lost.
At her lowest weight she was just 34kg (five stone six pounds).
Helping Sam beat her anorexia has made the sisters closer than ever
"It really shocked me," said Charlotte. "She used to be gorgeous as she was but she'd lost so much weight.
"She'd lose concentration because all she could think about was food. She had to think what she would do with it and how she could avoid eating it without us noticing."
The twins' relationship also started to suffer.
Charlotte kept a close eye on Sam and they had a group of friends who supported them both but anorexia kept Sam in her own little world.
"I was so focussed on food," she said. "It was only when I started coming out of it that I realised the effect it was having on Charlotte and everyone else.
"We did talk but we weren't really really close anymore. We never really told each other secrets, which we always used to do, and we kind of lost our bond."
Sam's family tried everything to help her get better.
They made special foods, took her to centres that specialised in eating disorders and her mum even went back to school to learn more about anorexia to see what else they could do to help Sam recover.
Three years on, Sam has gained about 15kg (two stone six pounds) and is happy and healthy again. And the twins' relationship is better than ever.
"We've got our bond back and it's made us stronger," said Sam. "My friends have commented on how much better I look now and it's made me realise who my proper friends are."
"We had about four school friends who were amazing," said Charlotte. "They helped me cope and helped Sam feel more confident."
The girls are agreed that if you're worried someone you know may be developing eating problems you should tell someone you can trust.
"Get help," said Sam. "Definitely tell someone straight away."
"When you find evidence, like them chucking their lunch away, that's when you can confront them," added Charlotte.
'Never give up'
"Otherwise they could just say they're not hungry and deny it and start trying to cover it up.
"But never give up because even through the hard times you just have to think of the positives.
"When you get through it it's just the most amazing feeling. We're so close now and everyone gets on so much better because we've been through this and we're stronger."