Dr. Oz Dr. Oz

He's not just trying to save a life, he's also trying to save a marriage. On today's episode of The Dr. Oz Show, Dr. Mehmet Oz brings back severely obese viewer favorite Colleen Williams and her husband, Derrick, for their third appearance on the syndicated show. The 31-year-old Phoenix woman, who recently tipped the scales at 700 pounds, is working with Oz and his team of trainers, nutritionists and shrinks on a no-baloney weight-loss program. (So far, she's shed 30 pounds.) Oz also has reality star Ruby from The Style Network — herself a former 700-pounder — serving as Colleen's mentor.

It's an epic undertaking, complicated by the Williams' increasingly strained relationship. For years, Derrick — a classic enabler — has waited on Colleen hand and foot, feeding and bathing her because she can't (or won't) do things for herself. During their last appearance, Oz labeled them both addicts: She's addicted to being a manipulator; he's hooked on being bossed around. "And both fear that dynamic will change when Colleen loses the weight," says Oz.

He considers marriage counseling just another part of his job description, but he's careful not to intervene too much. "What people really want from their doctor is to be heard," Oz says. "A lot of us in the medical field aren't too good at that, and it causes unnecessary grief. I learned this from Oprah: My patients may use code words like weight, pain or depression, but what they're really asking is 'How do I live my best life?'"

Adds the good doctor: "You want to know the most important thing I've learned since having my own show? To stop talking so much and to listen more."

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