Sarah Ferguson says her bottom "saved [her] life".
The Duchess of York is grateful she was only addicted to food during her younger years when her mother, Susan Barrantes, divorced Sarah’s father, Major Ronald Ferguson, when the royal was just 12 years old.
She said: "When I was 12, I became a compulsive eater and used food as my emotional tool [to cope] with the loss of my mother, who went to live in Argentina.
"But I always say the size of my bottom saved my life because my addiction was to food, not anything else.
"You beat yourself up, suffer self-doubt, then you hate yourself because you know you shouldn’t be eating."
The 57-year-old royal – who recently became a British Heart Foundation ambassador – has since slimmed down, partly helped by a move to Switzerland in October 2013, where she used "the mountains as [her] gym", but also got angry at the picturesque peaks.
Speaking to HELLO! magazine, she added: "I was furious with myself for getting to 187lbs. Furious. I would go and scream at the poor mountains. I’m a redhead and a Scottish and Irish mix so the mountains got it."
Sarah recently admitted she always used to wish she had bulimia when she was younger so that she could be as "beautiful and thin" as her former sister-in-law Princess Diana, who tragically died in a car crash in Paris in 1997 aged 36.
She said: "I was a binge-eater. I never could get bulimia because I just didn’t have that mental state to go that far, but I always wished I could.
"But that just shows you how dangerous and what place I got to. To wish you could have a mental illness to that level is a very serious place to get to."
Sarah Ferguson: My bottom saved my life
