Twiggy was eating "everything" at the height of her modelling fame.
The 77-year-old model - who was discovered in 1966, at the age of 16 - has claimed that her "metabolism" has always been the secret to her slender figure.
Twiggy told People: "I was just born that way.
"If you saw what I used to eat, it was everything. It was just my metabolism. My father was built the exact same way. And I was so young!"
Twiggy is now more health-conscious than she used to be.
She said: "I can’t eat like that now. Your body changes. I have to try to eat healthily now."
Earlier this month, Twiggy explained how her life was changed by a trip to a hair salon.
The model was initially discovered in improbable circumstances, after a fashion editor saw a photo of her in a London hair salon.
Twiggy told People: "It was mad, really.
"I couldn’t have planned any of it. If I’d gone to a modelling agency and said ‘I’d like to model,’ they’d have turned me away. I was too short. I was too small. I just didn’t have the measurements."
In 1966, Twiggy headed to a salon in preparation for a night out.
The iconic star said: "It was serendipity, because I went to that salon to have my hair styled, and Leonard [Lewis, the celebrity hairdresser], saw me and said, ‘Can I cut your hair?’
"The funny thing was, I didn’t want my hair cut, because I was a mod, and I liked it long and parted in the middle.
"[But] because I was so timid and in this posh Mayfair salon, I was too shy to say no to him!"
Twiggy ultimately walked out of the salon with her iconic pixie cut, and she now admits that the distinctive look changed her life.
She said: "The photographer, Barry Luttigam, that was the first shot he did of me, which is amazing really, because it became the most famous shot. He just pulled me in front of the camera and said, ‘Look in the lens, which is what I did."
A fashion journalist subsequently spotted Twiggy's photo hanging in the salon, before reaching out to her to offer some modelling work.
Twiggy added: "I didn’t look like anybody else at the time, which is why I think it all happened."
