Award-winning science writer Gary Taubes disagrees with the medical community’s most basic rules of dieting. Here, Gary challenges Dr. Oz to reexamine his fundamental assumptions about nutrition and why we gain and lose weight.

Click here to see Dr. Oz and Gary Taubes debate the effectiveness of exercise for weight loss.

Click here to read an excerpt from Gary’s book, Why We Get Fat.

Click here to watch Part 1.

Click here to watch Part 3.

After years of trying to get pregnant, doctors told Kelsi Pierce it would be near impossible for her to conceive a child. However, Kelsi got the surprise of her life when her mom volunteered to be her surrogate — and she found out she, too, was pregnant!