Historical Events

Lancet editors mock diet-heart hypothesis despite the power it held.

After the publication of NiHonSan and the trial on the Israeli civil servants, The Lancet took stock of the evidence in 1974. “So far, despite all the effort and money that has been spent,” wrote the editors, “the evidence that eliminating risk factors will eliminate heart disease adds up to little more than zero.”

“One thing is clear,” they continued about the two recently published epidemiological studies, “statistical association must not be immediately equated with cause and effect.” It was an obvious point but one worth repeating in a community of nutritional experts who were tempted to stretch the epidemiological evidence in favor of the diet-heart hypothesis.

The Lancet editors were consistently outspoken about adopting the diet-heart hypothesis too soon, and for many years, the debate in England was more lively and open than it was in the United States. In England, skepticism and even hostility toward the diet-heart hypothesis were widespread. The passionate embrace of the diet-heart hypothesis by American scientists was something that their British colleagues found perplexing. “There was a very big emotional component into the interpretation in those days,” said the influential British cardiologist Michael Oliver. “It was quite extraordinary to me. I could never understand this huge emotion towards lowering cholesterol.” His colleague in the United Kingdom, Gerald Shaper, the researcher who studied the Samburu tribe in Kenya, also found the American diet-heart proponents incomprehensible: “People like Jerry Stamler and Ancel Keys raised the blood pressure of British cardiologists to a level which was not believable. It was something strange; it was not rational, it was not scientific.”

The Lancet editors sometimes mocked the American obsession. Why would Americans put up with the sacrifices of a low-fat diet? They were appalled that “some believers long past their prime were to be seen in public parks in shorts and singlets,XVII exercising in their free time, later returning home to a meal of indescribable caloric severity [when] there is no proof that such activity offsets coronary disease.”

The Lancet also sounded a note of alarm that would soon be picked up by others: “The cure should not be worse than the disease,” wrote the editors, echoing the medical dictum, “First, do no harm.” Perhaps reducing fat in the diet might lead to some unintended consequence, such as a lack of “essential” fatty acids in the diet (these are fats that the body itself cannot make). In fact, Seymour Dayton was concerned about the extremely low levels of arachidonic acid, an essential fatty acid present mainly in animal foods, among his prudent dieters. Another possible consequence of cutting back on fat was the seemingly inevitable increase in carbohydrate consumption that would result, for the simple reason that there are only three kinds of macronutrients: protein, fat, and carbohydrates. Reducing animal foods (mainly protein and fat) shifts consumption toward the only type of macronutrient remaining: carbohydrate. In practical terms, a breakfast without eggs and bacon (fat and protein) becomes one of cereal or fruit (carbohydrates). Dinner without meat is often pasta, rice, or potatoes. Experts now lament that this dietary change came to pass in the latter half of the twentieth century, with disturbing results for health. The Lancet’s fear was therefore clearly justified.

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