Oprah Winfrey Oprah Winfrey

Never one to be reticent about her weight, Oprah Winfrey is once again publicly sharing her diet struggles. The talk show queen reveals in the January issue of O magazine that she currently weighs 200 pounds and is "mad" that she has again let herself go.

"I'm embarrassed," she writes in the article. "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?'"

Since slimming down to 160 pounds two years ago, Winfrey has "fallen off the wagon" due to a thyroid problem that caused a "fear of working out."

"I was so frustrated I started eating whatever I wanted — and that's never good," she said.

One of Winfrey's lowest points came in April during a taping with Cher and Tina Turner in Las Vegas where she "felt like a fat cow." Her new figure also means a new gown for President-elect Barack Obama's inauguration as she is "not sure" the one she designed on her "vision board" a year ago will fit.

But, not one to be down and out, Winfrey, who once tipped the scales at 237 pounds, is determined to get fit again — although not necessarily thin. The 54-year-old will address her yo-yoing weight on the Jan. 5 episode of The Oprah Winfrey Show, which will kick off "Best Life Week" and hopefully a new and healthy O.

"I definitely wasn't setting an example," she writes. "I was talking the talk, but I wasn't walking the walk. And that was very disappointing to me."