"The theory was that a low-fat/high-carb diet would control weight and help prevent killer diseases. But most of the studies that followed actually failed to show a direct link between fat in the diet ad heart disease and cancer. But by then it was too late--even science couldn't shake the prevailing wisdom that all fats are bad, and all carbs are good," explained Johnson.

By investigating the genesis of this theory, Taubes found that the government's initial decision 30 years ago to promote low-fat diets was not based on recommendations from doctors or scientists, but rather from lawyers who worked for Sen. George McGovern in the mid-1970s.

"They come out with this document and it just sets this ball rolling where finally some government body is telling Americans to eat less fat and eat more carbohydrates," Taubes said.

With the release of the government's "Food Pyramid" in the early 1990s, it was official: the low-fat/high-carb diet was America's food plan. At the pyramid's base are the foods considered the staple of the healthy low-fat diet: refined carbohydrates such as bread, cereal, rice and pasta. At the narrow top--indicating that they should be used sparingly, if at all: fats and oils.