In a world of fad diets and ever-changing ideas on how to get thin, Gary Taubes is not just another diet guru but a journalist who has covered science for the past 30 years.
It was Taubes who wrote the eye-opening -- and controversial -- New York Times magazine cover story five years ago that asked the near-blasphemous question: "What If Fat Doesn't Make You Fat?"
Now he's at it again. He's expanded that article into a new book, "Good Calories/Bad Calories: Challenging the Conventional Wisdom on Diet, Weight Control, and Disease." In the book, Taubes looks back at some 50 years of scientific research on why we get fat. He blames the bread.
"My wife likes to refer to me as the Grinch who's trying to steal Christmas," Taubes said.
And not just the bread, but the whole family of complex carbohydrates. So "Nightline" took Taubes to lunch, and what better place to discuss the dangers of carbohydrates than Raffaele's, an Italian restaurant on Manhattan's East Side, where we could talk -- over bread and pasta -- about carbs and fat, good science versus bad.
Taubes said that after rereading years of scientific research, he has found proof that for the last half century, science has just gotten it wrong: It's not fat that is making Americans fat, he said, it is the base of the food pyramid, the complex carbohydrates, foods such as bread, pasta, potatoes. It's the starches we were told we needed that make us pudgy.
It's simple chemistry, said Taubes. Carbs spike insulin. Insulin creates sugar. And sugar packs on the pounds.
"The grains are carbohydrates," Taubes said. "They're refined carbohydrates. You take off the shell and all the protein and the vitamins, and you refine it down, and you end up with something that its primary effect on the body, immediate effect, is to raise insulin levels. And if you raise insulin levels, what that does is drive calories into your fat tissue. Raising insulin literally works to make you accumulate fat. This is one of these phenomena that for some reason the medical research establishment has chosen to consider irrelevant to why we get obese."
It's a theory that Taubes claims is simple -- and anthropological. It evolved from our days as hunter-gatherers, before we ate refined carbohydrates and sugars.
"And all we're saying [in the book] to do is, 'Don't eat these foods we didn't evolve to eat.' It's conceivable that switching to a diet absent these foods, making the transition has side effects that we have to deal with, that doctors have to deal with," he said. Click here to read an excerpt of Taubes' book.
"Carbs are not killers," said New York nutritionist Carol Forman Helerstein. "Mother Nature would not have put carbs on the face of the earth if they were killers. If you go back to our ancestry and you look at the caveman, what did he eat? He ate carbs."