Low fat, saturated fat, and sugar: the confusion continues

This month two reputable doctors, horrified by the rise in bariatric surgeries to reduce the harms associated with diabetes, published an op-ed on the front page of the Sunday Review of the NYTimes sharply suggesting that we’re doing it all wrong with it comes to medical measures recommended for diabetics.

Most doctors — and the diabetes associations — portray diabetes as an incurable disease, presaging a steady decline that may include kidney failure, amputations and blindness, as well as life-threatening heart attacks and stroke. Yet the literature on low-carbohydrate intervention for diabetes tells another story. For instance, a two-week study of 10 obese patients with Type 2 diabetes found that their glucose levels normalized and insulin sensitivity was improved by 75 percent after they went on a low-carb diet.

At our obesity clinics, we’ve seen hundreds of patients who, after cutting down on carbohydrates, lose weight and get off their medications. One patient in his 50s was a brick worker so impaired by diabetes that he had retired from his job. He came to see one of us last winter, 100 pounds overweight and panicking. He’d been taking insulin prescribed by a doctor who said he would need to take it for the rest of his life. Yet even with insurance coverage, his drugs cost hundreds of dollars a month, which he knew he couldn’t afford, any more than he could bariatric surgery.

Instead, we advised him to stop eating most of his meals out of boxes packed with processed flour and grains, replacing them with meat, eggs, nuts and even butter. Within five months, his blood-sugar levels had normalized, and he was back to working part-time. Today, he no longer needs to take insulin.

The paper ran a follow-up story by one of its best medical reporters, Gina Kolata, that cast some doubt on the simplicity of this recommendation.

But there are no large and rigorous studies showing that low-carbohydrate diets offer an advantage, and, in fact, there is not even a consensus on the definition of a low-carbohydrate diet — it can vary from doctor to doctor.

“There have been debates for literally the whole history of diabetes about which kind of diet is best,” said Dr. C. Ronald Kahn, chief academic officer at Joslin, and no relation to Dr. Richard Kahn. But, he said, “the answer isn’t so straightforward.”

The diet question arose again in the public discourse with the revelation last week that the sugar industry (the Sugar Foundation) backed a study way back in the 1960’s that shifted blame for heart disease from sugar — which is where the evidence was pointing at the time – to saturated fat.

The sugar industry paid scientists in the 1960s to play down the link between sugar and heart disease and promote saturated fat as the culprit instead, newly released historical documents show.

The internal sugar industry documents, recently discovered by a researcher at the University of California, San Francisco, and published Monday in JAMA Internal Medicine, suggest that five decades of research into the role of nutrition and heart disease, including many of today’s dietary recommendations, may have been largely shaped by the sugar industry.

“They were able to derail the discussion about sugar for decades,” said Stanton Glantz, a professor of medicine at U.C.S.F. and an author of the JAMA Internal Medicine paper.

It’s now the medical consensus that processed foods — which typically include unnecessarily added sugar — worsen heart disease. But it’s easy to overlook the fact that — then and now — researchers also suspect that saturated fat worsens heart disease. Saturated fat vs fat overall was an issue I wrote about a couple of years ago: although unsaturated fats, such as the olive oil that is at the heart of the Mediterranean diet, are considered healthy, the saturated fats found in butter, meat, and cheese do not get off so easily.

As NPR said, discussing the sugar study from the l960’s:

The review minimized the significance of research that suggested sugar could play a role in coronary heart disease. In some cases the scientists alleged investigator incompetence or flawed methodology.

“It is always appropriate to question the validity of individual studies,” [JAMA author] Kearns told Bloomberg via email. But, she says, “the authors applied a different standard” to different studies — looking very critically at research that implicated sugar, and ignoring problems with studies that found dangers in fat.

Exactly. As Dr. David Katz, editor of Childhood Obesity, and a professor at Yale, put it in a Forbes column:

Almost everyone who ultimately winds up considering bariatric surgery has tried every diet under the sun. When you recall that some of the most popular diets of recent years, from Atkins to South Beach, have been “low-carb,” the notion that this is the road too seldom taken can only be proffered by those lost in the woods.

A low-carb diet has certainly been among the attempts made by almost every patient I have ever referred for bariatric surgery, helped to find an alternative to it or treated after. Low-carb diets work in the short term like almost every other diet, and generally fail over time like every other diet for just about everybody.

Katz writes unusually sharply for a doctor:

As I noted recently, there is a booming cottage industry now, amplified at every turn by those directly interested in selling beef and perhaps butter, in peddling the notion that saturated fat has not only been exonerated of all ills (it has not), but is actually good for us now (but for biochemical nuance, this is plain baloney).

The problem with “the sugar did it!” is that we tend to process such revelations as an endless sequence of either/or choices: it was either sugar or saturated fat. That’s perilously silly.

Leaving aside the truly devastating environmental implications of encouraging moremeat intake by nearly 8 billion Homo sapiens at a time of climate change, desiccating aquifers, deforestation and biodiversity itself on the endangered list–there is the simple fact that dietary patterns reliably associated with good health outcomes across study methods, global populations and decades are high neither in sugar nor in saturated fat. They are, instead, high in wholesome foods, mostly plants–every time.

Or, as HL Mencken put it:

There is always a well-known solution for every problem — neat, plausible, and wrong. 

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