Oprah Winfrey blames the mild depression she suffered after gaining so much weight last year on working too much at the expense of taking the time to relax.
Winfrey yesterday confessed on her U.S. television show that she was miserable - although she never came out and admitted she had depression - and vowed to change her attitude towards food.
The 54-year-old, who at one point tipped the scales at 14.3 stone, said she was determined to change in 2009.
She said: 'It's not about the food. It's about using food - abusing food.
'Too much work and not enough play. Not enough time to come down. Not enough time to really relax.
'I am hungry for balance. I'm hungry to do something other than work.
Winfrey, who has been diagnosed with a hormonal imbalance known as hypothyroidism, says she is now devoting more time from her 14-hour workday schedule to her own well-being, which includes regular exercise.
She revealed that last year she was forced to mask her figure every month for her cover shot on her O magazine.
She told viewers: 'I've been hiding my body because I didn't want you to see it.
'Here I am, one of the most visible people in the world, trying not to be seen on the cover of my own magazine.'
For O's January issue, which she showed off on her show yesterday, Winfrey poses next to a picture of her former svelte self, from 2005 - when she weighed 11.4 stone.
'This is the year of hopefulness,' she insisted. 'My goal is to be the weight that my body can hold and be healthy and strong and fit and be itself.'
Winfrey said she began suffering sleep issues and heart palpitations over a year ago.
'None of the doctors recognised it was a thyroid problem, but our viewers did,' she said. 'The moment I heard I had a thyroid problem, I thought I don't even know how to fight this. It's about balance. When I ask myself what I am hungry for, I am hungry for balance.'
Her fitness guru also appeared on yesterday's broadcast and said Winfrey had lost her 'zest for life'
Bob Greene said he was alarmed at the change in the behaviour of the chat show queen, who has struggled with her weight throughout her life.
He said things got particularly bad in 2008 when she couldn't shift the extra pounds.
'I looked in her eyes, and she wasn't there,' he said. 'She was very vacant and distracted. It was alarming to me.
'I think I felt she was losing her zest for life, and that was one of the saddest moments.'