After refusing medical tests for 15 years, Colleen begins treatment at a top weight-loss clinic. Dr. Oz introduces her to the team of experts that will work with her.

Click here to watch Part 1: Dr oz begins his intervention with a house call. 

Click here to watch Part 2: Colleen admits why she is afraid to lose the weight.

Click here to watch Part 3: Colleens husband and mother join the show.

Click here to watch Part 5: Oz explains Colleen's shocking test results

Click here to watch Part 6: Colleens mentor, Ruby, promises to help her lose the weight.

Blood tests courtesy of Biophysical Corporation

Want to help lower your risk of getting cancer? The answer could be in the food you eat! Dr. John Whyte, chief medical officer at WebMD and the author of "Take Control of Your Cancer Risk," says there are three kinds of foods that could really help prevent cancer: garlic, fish and grapes. And what three kinds of foods should you avoid? Red and processed meats, refined grains, and alcoholic and sugary drinks. Watch the videos below to learn more about how food could be connected to your cancer risk.