Chloe Frame, 20, became so determined not to eat that she feared even using toothpaste would cause her to put on weight.
At the height of her illness Chloe’s periods stopped and her hair began to fall out, and she was only sleeping two hours a night.
Chloe's problems began aged 18 when her parents divorced, and she says she began to starve herself in a bid for attention.
But a girls holiday to Magaluf in June last year saved her life when her pals noticed how thin she was and told her parents.
The university student, from Ayr, South Ayrshire, is now recovering with the help of private counselling - but feared her illness may have left her infertile.
Chloe said: "When it started, my mum and dad were getting divorced and I wasn't getting the attention I was used too.
"I started becoming obsessed with food and thought if I lost weight maybe that would get me the attention from my family.
"I started restricting what I was eating.
"But the weight wasn't coming off quick enough. So I started starving myself all day.”
"Even when I brushed my teeth, I would only use a tiny bit of toothpaste because I was so worried it would make me put on weight."
Phobia of supermarkets
As the illness took hold, Chloe developed a fear of supermarkets - and each trip would end up lasting three hours as she desperately searched for the lowest calorie foods.
She began trawling online grocery stores in a bid to find foods with no calories.
Chloe said: "I developed a phobia of supermarkets, I would find them totally overwhelming to be in.
"I would spend three hours shopping looking at the calorie content of each thing to make sure I got the one with the least in it.
"When I started getting scared to go in them, I would sit at home instead, spending hours on my phone looking at their websites to find food with zero calories.
"I think I was also taunting myself, looking at all the things I couldn't have. It was the same with restaurants, I was scared to eat out.
"It was exhausting and I was always so hungry.
"I was so cold all the time, I was only sleeping for about two hours a night, my periods stopped and my hair fell out in massive clumps.
"At one point I was constipated for four weeks. I was so weak and tired but was still trying to do 25,000 steps a day while eating no food.
"I would say 'I will stop when I get to this weight', but then when I reached it, I would just keep going.”
But an intervention finally came following a boozy holiday to Magaluf - when Chloe restricted her eating even further to allow for calories from her alcohol consumption.
She said: "When we went on holiday to Magaluf I was drinking so I really tried not to eat anything at all because I was so determined to stay thin.
"But my friends started noticing, so one of the days I ate three chicken nuggets and was sick right away because I just couldn't live with the guilt.
"When we got home my friends told my parents and that's when I knew I had to make a change. The holiday saved my life because that's when my friends started noticing.
"I was a really bubbly and happy person, who always enjoyed food, no one could believe this happened to me."
Last July she began seeing a counsellor, and she has now returned to a healthy weight and is enrolled on a course at Glasgow Caledonian University.
She said: "My periods only came back two months ago and I was really worried that I was going to be infertile.
"I had to cut my hair into a bob because it was so thin, and then get extensions to try and make it look thicker because I lost so much.
"But the counselling has helped me cope and I no longer have anxiety and depression because of my eating disorder.
"I still eat a healthy diet but I don't weigh myself anymore. The thoughts can sometimes be there but it's gradually getting better."
Information and support for those suffering from an eating disorder can be found on the Scottish Eating Disorders Interest Group (SEDIG) website.