Refined Grain Further Out Of Favor

(CBS)  Bread has been portrayed as Public Enemy No. 1 for low-carb dieters trying to slice inches off their wasitlines. But, reports CBS News Correspondent Serena Altschul, there's growing scientific evidence showing that idea to be a misconception.

"It's not just the total carbohydrates, but it's about the types of carbs you are consuming that will affect your waistline," says P.K Newby of Tufts University.

In two studies spanning three years, scientists at Tufts followed the eating habits of over 450 healthy middle-aged people. They compared those who ate foods high in refined flour — like white bread — to those with diets loaded with whole grain products.

"Those individuals in the white bread group had about a half-an-inch larger waist circumference than compared to those in the healthy high fiber group," Newby says.

But, remarks Altschul, the real shocker is that the white bread lovers with the expanding waistlines ate less total carbohydrates than whole wheat eaters. It was the white bread that made the difference.

Here's why: Researchers believe refined flour in white bread metabolizes faster in the body than whole grains. That causes a spike in insulin. The rush of insulin turns into fat more quickly -- right on your waistline.

Cathy Nonas of the American Dietetic Association says, "You can see that, if someone was eating like that for ten years, it would make not only a significant difference, but it would be a significant risk to their health profile."

Food manufacturers are already looking to cash in, Altschul notes.

Conagra -- one the companies that originaly brought refined flour to American grocery shelves -- has rolled out a new product claiming the taste and texture of white flour, with the benefits of whole grain.