Dietary Fat Guidelines Were Flawed From The Beginning

From the start, guidelines were not supported by clinical evidence

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In 1977, the US government published its first set of dietary guidelines for Americans, aimed specifically at reducing cardiovascular disease. In 1983, the National Advisory Committee on Nutritional Education in the United Kingdom followed suit with identical guidelines.

The effort in the US was spearheaded by the Senate’s Select Committee on Nutrition and Human Needs, chaired by Senator George McGovern.

The dietary guidelines urged by this committee quickly became dogma not only to government agencies, but also to the American Heart Association, the American College of Cardiology, all American physicians, and the entire food processing industry. We all know what those guidelines said, because (despite what we’ve learned since then) we are still inundated with the message from nearly every direction: 1) Limit the amount of total fats in your diet. 2) Don’t eat saturated fats. 3) Don’t eat foods containing cholesterol.

These dietary recommendations were not based on clinical evidence compiled from randomized clinical trials (RCTs), but rather, were based on the cholesterol-heart disease hypothesis, which goes like this: Cholesterol causes heart disease; eating fat (especially saturated fat) increases cholesterol levels; therefore, dietary fat causes heart disease.

    Even in 1977 dietary experts did not all agree on this. Some brave souls cautioned the Senate committee that there really wasn’t any clinical evidence that the guidelines they were proposing would be helpful, and that, perhaps, urging a drastic change in diet for more than 200 million people without good clinical evidence might not turn out to be a smart thing.

    McGovern’s famous retort (“Senators don’t have the luxury of waiting until every last shred of evidence is in”), effectively shut down the dissenters (or, as they would be called today, “deniers,”) and the world has subsequently been treated to nearly 40 years of highly coordinated and heavily funded dietary propaganda about the benefits of low-fat, low-saturated fat, low-cholesterol diets.

    In recent years however, enough clinical evidence has been compiled to convince a growing body of dietary experts that this dogma is wrong. Indeed, the most recent US Dietary Guidelines quietly dropped the low-total-fat recommendation without much comment, and with no fanfare. In 2015, the Guidelines are poised to “allow” the consumption of high-cholesterol foods (like eggs). And, while the recommendation for severely limiting saturated fats apparently will remain, the rationale for keeping this recommendation is under significant fire. Slowly, glacially, the “real” clinical science is acting as a needed corrective to the “settled” clinical science that has driven American dietary guidelines for so long.

     

    Wrong From The Beginning

    In 2015, a group of investigators writing in the medical journal Open Heart published a meta-analysis of the RCTs that were, in fact, available to dietary experts between 1977 and 1983, on the benefits of low-fat, low-saturated fat, low-cholesterol diets.

    These investigators identified six dietary trials that were then available, involving 2467 men at increased risk for heart disease, most of whom already had heart disease. These men were randomized to diets restrictive in fats, or to control groups without these dietary restrictions. The meta-analysis found that, while cholesterol levels were indeed reduced among men randomized to low-fat diets, there was no corresponding reduction in either overall mortality or subsequent heart disease.

    Therefore, at the time the original dietary guidelines were being promulgated and converted to dogma, evidence was indeed available from RCTs, and none of this evidence indicated that the dietary recommendations the experts were pushing would do any good. Notably, neither the Americans nor the Britons referenced these RCTs in their publications on their new dietary guidelines.

    The authors of the meta-analysis conclude, “The present review concludes that dietary advice not merely needs review; it should not have been introduced.”

    The Bottom Line

    The history of the US Dietary Guidelines ought to serve us as an object lesson. The expert panel that produces and revises these guidelines, like all expert panels commissioned with the task of determining public policy with regard to individual behaviors and individual choices, is probably well-meaning, but is inevitably agenda-driven. Therefore, the intelligent citizen ought to approach the work product of such expert panels with an attitude of respectful skepticism. Real science not only welcomes such skepticism, but is founded on it.

    And the degree to which your skepticism is greeted with disdain, dismissal, or even hatred, is directly proportional to the degree to which the “experts” are working from an agenda, rather than from a position of objectivity.

    Sources:

    Harcombe Z, Baker JS, Cooper SM, et al. Evidence from randomised controlled trials did not support the introduction of dietary fat guidelines in 1977 and 1983. Open Heart, 2015:2(1).

    Select Committee on Nutrition and Human Needs. Dietary goals for the United States. 1st edn. Wathington: US Govt Print Off, 1977.

    National Advisory Committee on Nutritional Education (NACNE). A discussion paper on proposals for nutritional guidelines for health education in Britain. 1983.

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