The deeply-ingrained idea that saturated fat equals heart disease and cancer is an idea that took root quite independently of the science, says Gary Taubes in Good Calories, Bad Calories. In 1977, while the issue was still being hotly debated within the scientific community, the United States government took a position, and with the publication of Dietary Goals, began its determined push toward dramatic reductions in fat consumption.
According to Taubes, Dietary Goals “took a grab bag of ambiguous studies and speculation, acknowledged that the claims were scientifically contentious, and then officially bestowed on one interpretation the aura of established fact.” But many prominent investigators, the American Medical Association, the National Institutes of Health (NIH) and the FDA were of the view that the guidelines were premature and irresponsible. Once politicized, however, health issues tend to take on a life of their own.
A number of key studies attempting to support the saturated fat-disease hypothesis within different populations were published in the 1980s. None of them succeeded. What they found instead was that low cholesterol levels were associated with a higher risk of cancer, and that high-fat diets were significantly associated with a lower risk of total mortality, cancer mortality and stroke mortality.
One of these studies—the Multiple Risk Factor Intervention Trial, which followed 12 000 men for seven years—surprisingly found a higher death rate among the treatment group that had lowered their cholesterol intake, quit smoking and treated their high blood pressure than among the control group left to do as they pleased.
I'd think that study alone would have made us stop and wonder about the wisdom of pursuing ever-lower cholesterol levels, but it didn't.
More studies were done in an attempt to confirm the fat-is-bad hypothesis. Though none of them succeeded, the idea that fats were bad persisted. The National Heart, Lung, and Blood Institute (NHLBI) marched full-steam ahead with their campaign to bring down our cholesterol levels, and the media, as it tends to in response to press releases, went along with it. Whole milk, butter, fatty meats and eggs became taboo.
The NIH, initially skeptical, eventually hosted a “consensus conference” and effectively put an end to three decades of debate. The conference report failed to mention dissent, though that was anything but true.
Officially settled by declaration of consensus, margarine and vegetable oil consumption continued to rise steadily, butter consumption continued to decline—and heart disease, cancer and diabetes began their relentless climb upward. In 1910, when mortality from heart disease was low, per capita butter consumption was 18 pounds; by the year 2000, it was less than four pounds. The lifetime risk of Type 2 diabetes when we were eating all that butter in 1910 was one in 30; now it is one in three. Why have we clung to the idea that saturated fats are bad? Researchers know that if their research fails to support official positions, funding will go to another researcher. To dissent was, and is now, to forgo research funding. Research, once politicians and the media have done their thing, tends to focus more on being reconciled with the current wisdom rather than on challenging it.
The shift away from butter and toward low-fat, no-fat, or vegetable and trans-fat content also resulted in increasing sugar intake, particularly fructose intake. We look for satisfaction when we eat, and fat content brings satiety. What we lost with the shift away from the nourishing traditions of butter and eggs and animals fats was replaced with overall higher carbohydrate intake.
We now know that the predictors of heart disease include high insulin production, insulin resistance, high triglycerides, and low levels of HDL cholesterol. We also know they are conditions strongly linked to diets low in fats and relatively higher in carbohydrates. But despite our knowing this, we're still doing little to address metabolic syndrome.
The president of the American Heart Association, Anthony Gotto, told Time in 1984 that if everyone went along with a cholesterol-lowering program we'd have heart disease conquered by the year 2000. We've clearly done no such thing; it is a failed hypothesis.