With her 60th birthday approaching on January 29 — Oprah Winfrey’s efforts for a healthy new look and attitude are more apparent than ever after years of yo-yo dieting.

Now, her colleague Dr. Mehmet Oz tells Closer Weekly that less stress in her life was a massive contribution to her weight loss this time around!

“When stresses in life get managed better, the weight comes off,” Dr. Oz tells Closer adding, “It’s great news for her!”

The media mogul has been able to focus more on her health now that she doesn’t have the daily grind of hosting a talk show and is living full-time in Montecito, Calif. And that means less stress — and body fat!

“When you have extra weight on board, it’s usually your body’s response to stress,” Dr. Oz said.

“She is ready to face this decade,” a longtime friend confides to Closer, “Looking and feeling the best she has in years.”

The famous doctor has been a health expert on The Oprah Winfrey Show for the last five seasons. His TV career was launched after he first appeared on the show in 2004.

Then in 2009, the Dr Oz show – a program about medical issues and personal health, was launched by Winfrey's Harpo productions and Sony Pictures.