Having packed 40 pounds onto her former 160-pound self, Oprah Winfrey is declaring, "I'm mad at myself" in the January issue of her O magazine released on Tuesday, People Magazine reported.

"I'm embarrassed ... I can't believe that after all these years, all the things I know how to do, I'm still talking about my weight. I look at my thinner self and think, 'How did I let this happen again?" the media mogul, 54, writes.

Winfrey memorably revealed her new look on her show in 1988 - by wheeling out a wagon loaded with fat to represent the 67 pounds she had shed. On that episode, she sported a pair of size 10 Calvin Klein jeans.

Choosing a gown for the Barack Obama inauguration coming up in January made Winfrey realize her self-image was no longer jibed with the person standing on the scales.

"I felt like a fat cow," Winfrey writes of the occasion when she sought to skip out on a Las Vegas show taping with Cher and Tina Turner.

The TV star intends to address the issue on The Oprah Winfrey Show, which will kick off "Best Life Week" on January 5.