Editor's note: Nina Teicholz is the author of the book, "The Big Fat Surprise: Why Butter, Meat and Cheese Belong in a Healthy Diet." She can be found at www.thebigfatsurprise.com and @bigfatsurprise The opinions expressed in this commentary are hers.

(CNN) -- Eating fat helps heart health and weight loss, concluded a widely reported clinical trial this week.

The result did not surprise close followers of nutrition science since it echoed a decade's worth of similar studies. But, unlike its predecessors, the new trial was not ignored by nutrition experts and the media; that was the real news. It's a sign that a half-century-long fear of dietary fat might finally be melting away, exactly the breakthrough needed to start healing the nation's health.

When Americans were placed on a low-fat diet in the 1970s, the scientific evidence behind it was thin. Yet, desperate to combat the nation's epidemics of heart disease and cancer, the scientific establishment rallied behind the low-fat dogma. And the idea that eating fat makes you fat has long had a certain intuitive appeal.

Ever since, challenging the conventional wisdom on dietary fat has been a form of professional suicide for nutrition experts. Critics faced near-certain retribution: They had trouble getting papers published, lost research grants and were frozen out of expert panels.

"For a generation, research on heart disease has been more political than scientific," lamented George Mann, a professor of biochemistry and prominent expert throughout the 1970s. He himself had been warned by a secretary at the National Institutes of Health that if he kept up his sustained criticism of the low-fat diet, he would lose his research grant, which he did.

Skeptics pointed out that the low-fat diet had never been properly tested before being recommended to the public. A remarkable 30 years passed before trials were conducted, and then the results were entirely disappointing.

Indeed, in the largest-ever dietary trial in history, called the Women's Health Initiative on nearly 50,000 women, researchers found in 2006 that subjects who followed a low-fat diet for an average of seven years ended up only one pound lighter than those on a regular diet, and with hardly any advantage in preventing cancer, heart disease or diabetes. Robert Knopp, the now-deceased lipid specialist at the University of Washington who conducted some of the first low-fat trials, remarked to me that "there was a deafening lack of commentary" about these devastating findings.

Last year, an expert panel convened by the Swedish government reviewed the entire low-fat diet literature and determined that the universally recommended low-fat diet was ineffective as a tool for weight loss. If they had not been blinded by establishment bias, Americans would have come to the same conclusion based on our reality at home.

Over the past 30 years, we have dutifully reduced fat as a portion of total calorie intake by about 5% while increasing carbohydrates by about 25%—and yet we have only grown fatter and sicker.

Our own authorities have proven reluctant to investigate alternative ideas. The low-carb approach popularized by Robert C. Atkins in the early 1970s has been all but villainized for decades. The two main funders of nutrition science, the American Heart Association and the National Heart, Lung, and Blood Institute have long deemed an Atkins diet an unhealthy fad.

Despite these obstacles, a growing number of scientists over the past decade have conducted dozens of rigorous clinical trials on altogether thousands of people that tell an increasingly clear and consistent story: A low-carb diet has consistently been shown to be more effective in combating heart disease, obesity and diabetes.

Some of the results have been dazzling. In one trial, diabetes patients on a low-carb diet improved so dramatically that they were able to drop their diabetes medication. In another trial, subjects' blood pressure fell far more than those on a low-fat diet who were also taking blood-pressure medication.

Unfortunately, this story has long been ignored by the nutrition establishment. For instance, in 2008, the prestigious New England Journal of Medicine published a study that was twice as large and lasted twice as long as the one that appeared this week in the Annals of Internal Medicine. It produced similar results, with low-carb dieters performing far better than low-fat subjects. Yet this finding generated few headlines.

Moreover, there was no attempt to reckon with these successful low-carb trials in the expert report that informed the most recent Dietary Guidelines of the USDA, the body responsible for the nation's dietary health. The government maintains its longtime position that "healthy diets are high in carbohydrates."

Now, for the first time, the media and mainstream nutrition researchers are talking openly—and seriously—about the potential health benefits of a low-carb diet. If our error over the past half-century has been to shift too many of our calories from fat to carbohydrates, nutrition science, like any science, can correct itself—but only in this tentative new climate of open, unbiased debate.

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