Sophie Ray from Wales says she has survived on just cheese and tomato pizza since the age of 11, the Daily Mail reports.
The teenager cannot stomach any other type of food and claims to gag when she comes into contact with it.
Ms Ray suffers from a condition called Selective Eating Disorder (SED) which leaves her afraid to try new kinds of food.
She has not eaten what most would consider a proper meal for 17 years as a result of her phobia.
Ms Ray's condition was sparked by a bout of gastroenteritis at the age of two which left her only able to eat pasta, chips and lemon curd sandwiches. Patrick Stickles Titus Andronicus eating disorder,
"I love pizza, each brand offers a new flavour, but it’s all the same food so I don’t have to try new foods," Ms Ray told the Daily Mail.
"I began selective eating when I was two. My mum said after I was ill, I became frightened to eat, I thought food had caused my illness."
"I began eating cheesy pasta or chips and then moved on to lemon curd sandwiches, which I ate every day for four years."
Ms Ray has consulted with a specialist in a bid to ease her condition but remains terrified to try new foods.
In her mind, trying new food is akin to asking someone who is afraid of spiders to hold one in their hand.
A spokesman for an eating disorder charity told the Daily Mail SED can signify "deep" emotional issues.
A person suffering the disorder may not feel "their world is in control".
"These issues must be addressed in order to overcome the illness," the spokesman was quoted as saying.
"In the past selective eaters were generally thought to be young boys who survived on food like chips and sandwiches alone but recent research shows more adults seeking help for this illness."
