13/09/2012 13:12 BST | Updated 13/09/2012 13:28 BST

Lizzie Velasquez Answers Bullies Who Branded Her The 'World's Ugliest Woman' (PICTURES)

A woman who was born with no fat on her body has addressed online bullies who branded her the "world's ugliest woman".

Lizzie Velasquez suffers from a medical condition so rare there are only three known cases in the world.

Although doctors have been unable to pinpoint her syndrome, she exhibits some signs of the ageing disease progeria.

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lizzie velasquez

Fighting back: Lizzie Velasquez hit out at bullies on the Dr Drew Pinsky show

Lizzie, who cannot put on weight despite eating every 15 minutes, is also blind in one eye.

Speaking on HLN's Dr Drew Pinsky show, she revealed what it was like to be taunted over her appearance.

The 23-year-old said: "It's not easy, I will be the first to tell you it's not easy.

"I may have this outer exterior of people saying, 'She can handle everything, she's dealt with this for so long,' and to be honest, I'm human and of course these things are going to hurt."

"I think the biggest things I have to deal with is constantly people staring at me as soon as I walk into a room.

"Recently, it's been a lot of adults I've been having to deal with who will slowly walk in front of me and turn their heads, and look me up and down. So the stares are what I'm really dealing with in public right now."

But "instead of just sitting by and watching these people judge me, I'm starting to want to go up to these people and introduce myself, or give them my card, and say, 'Maybe you should stop staring and start learning.'"

In 2010, Lizzie, who wears size triple zero clothes, told The Telegraph: "I weigh myself regularly and if I gain even one pound I get really excited."

Lizzie was born four weeks prematurely, weighing just 2lb 10oz. The Texas State University student has never weighed more than 60 pounds.

Despite her difficulties, Lizzie hopes to become a motivational speaker and is the author of a new book - Be Beautiful, Be You.

Lizzie Velasquez