This is a short version of the lecture that Prof Tim Noakes gave at the close of the international low-carb, high-fat (LCHF) summit in Cape Town on February 22, 2015.
At heart, it’s about learning how to tell good nutrition science from bad. You’ll be able to assess whether Noakes really deserves to be Public Health Enemy Number 1 for promoting low-carb, high-fat (LCHF) diets. – Marika Sboros
By Tim Noakes
My critics have called me deluded and dangerous. In the South African Medical Journal in 2013, they said that I have cherry picked, misinterpreted data; that I don’t understand the science; I’ve lost my way, flouted the Hippocratic Oath; and I’m harming patients and the population.
Last year, for the first time in the history of the University of Cape Town, no senior academic has ever been criticised as publicly as I was.
Senior colleagues, including the Dean of the Medical Faculty at UCT (Prof Wim de Villiers who has since moved upwards and onwards – a reward for his bravery perhaps), sent a letter to the Dean of all South African medical schools and to the press.
“There is good reason for concern that this (LCHF) diet may rather result in nutritional deficiencies, increased risk for heart disease, diabetes mellitus, kidney problems, constipation, certain cancers and excessive iron stores in some individuals in the long term.”
They said that I was “making outrageous unproven claims about disease prevention, and maligning the integrity and credibility of peers who criticise his diet for being evidence-deficient and not conforming to the tenets of good and responsible science.
“This goes against the University of Cape Town’s commitment to academic freedom as the prerequisite to fostering responsible and respectful intellectual debate and free enquiry.”
The letter ended: “UCT’s Faculty of Health Sciences, a leading research institution in Africa, has a reputation for research excellence to uphold. Above all, our research must be socially responsible. We have therefore taken the unusual step of distancing ourselves from the proponents of this diet.”
The authors didn’t stop there. They ran a website in which they collected extraneous material, selected what they said was my argument and threw in blogs by people unrelated to the topic. All without giving me the right of reply.
Who is right?
Clearly, their goal was to prove that I’m deluded and dangerous. Rather than attacking the science, they attacked me personally . They said that I was practising junk science.
These are not horrible people. They were saying what they believed out of a deep sense of conviction.
Are they right, or am I right? We can’t both we right.
I will present the evidence to show that my opinion is scientifically based, does not break the rules of good science. I will show that I have a right to that opinion. And I will show that my critics are the ones who are practising junk science and endangering people’s health. They don’t understand causation science, hazard ratios, and insulin resistance.
The key problem is both sides believe the facts sit with them.
At the first international low-carb, high-fat summit in Cape Town, we spent three days discussing evidence for and against LCHF diets to treat insulin resistance.
Click here to read: Noakes on Banting: where it began, where it is going
Quality of the evidence
We need to begin by looking at the quality of the evidence. My critics say that low-carb diets are proven not to work. They also say that saturated fat is proven to increase the risk of cardiovascular disease (CVD). They say that we only have anecdotal evidence for low-carbohydrate, high-fat diets for the treatment of insulin resistance (IR) and diabetes.
That’s not correct.
We have the evidence: all randomised, controlled trials (RCTs) either show that high-fat outperforms low-fat diets, or long-term RCTs show no evidence that a low-fat diet does any good.
My critics have ignored all the RCTs and other evidence that disputes their theories. In so doing, they have not practised good science according to the rules laid down by British epidemiologist and statistician Sir Austin Bradford Hill. Bradford Hill is revered as the “father of medical statistics”.
A new science
Bradford Hill wrote a series of articles in 1937 describing the use of statistics in medical science. It was a new science. He was one who really understood it. He laid down levels of information for causation, starting from anecdote (case history). It included cross-sectional study, randomised, controlled, prospective, clinical trials. And finally, systematic review and meta-analysis.
Bradford Hill explained that it was possible to prove causation from associational studies. But only if you could meet certain criteria. He listed nine such considerations. I have focused in this paper on only two: coherence and strength of association.
Bradford Hill wrote in 1965: “Here then are nine different viewpoints from all of which we should study association before we cry causation.
“None of my nine viewpoints can bring indisputable evidence for or against the cause-and-effect hypothesis. And none can be required as a sine qua non. What they can do, with greater or lesser strength, is to help us make up our minds on the fundamental question. Is there any other way of explaining the set of facts before us? is there any other answer equally, or more likely than cause and effect?”
Bradford Hill designed and completed the first RCT in 1950 (Streptomycin in TB meningitis). With Sir Richard Doll, he “proved” that smoking causes lung cancer initially from an associational study (which cannot prove causation).
He found that the hazard ratio for lung cancer in smokers was 10 to 30 times higher than in non-smokers. Such a high value could only indicate causation, in his opinion.
Click here to read: Science in crisis: not just sugar souring faith in experts
Bradford Hill has since died. Many researchers have ignored his criteria and flipped into a model of junk science. These are scientists who are more interested in getting funding and more work. They are not interested in discovering how to make people healthier.
In science, the bar has dropped to the lowest level of scientific “proof” conceivable. So low that researchers now ignore what Bradford Hill taught. They accept any hazard ratio above 1.0 as definitive evidence of causation.
Poor Bradford Hill turns in his grave with every new publication.
That means you can now prove anything as a cause of anything. The result is that we have grown an entire discipline of nutritional science based on this improper understanding of Bradford Hill’s doctrines.
And we wonder why we have got it all so very, very wrong.
So all the associational nutritional studies used to justify the 1977 US (low-fat) Dietary Guidelines are based on studies with hazard ratios usually between 0.7-1.3. Bradford Hill would not have accepted any of these studies as evidence for causation. Nor would he have allowed them to be used as the sole justification for novel global dietary guidelines.
In fact, studies using such feeble criteria for causation are simply scare-mongering, the ultimate junk science.
In his book, The Rise and Fall of Modern Medicine, James Le Fanu says: “Bear in mind Sir Austin Bradford Hill’s insistence that statistical inferences by themselves have no meaning unless they are internally coherent. That is to say, when several different types of evidence for an association between an environmental factor and disease … are examined, they (must) all point to the same conclusion.”
“Put another way, no matter how plausible the link between dietary fat and heart disease might seem, just one substantial inconsistency in the statistical evidence effectively undermines it.”
Since most such studies originate from departments of epidemiology that consider themselves at the forefront of hard science, Le Fanu proposes a simple solution: “Meanwhile the simple expedient of closing down most university departments of epidemiology could both extinguish this endlessly fertile source of anxiety-mongering while simultaneously releasing funds.”
Interestingly, a Canadian report – A Systematic Review of the Evidence Supporting a Causal Link Between Dietary Factors and Coronary Heart disease – used four Bradford Hill criteria (strength, consistency, temporality and coherence) to evaluate all the evidence from dietary studies.
Foods to protect hearts
The study published in the Archives of Internal Medicine in 2009 showed strong evidence for vegetables, nuts, “Mediterranean” and high-quality dietary patterns for “protective effects against CHD”. These are exactly the components the Banting low-carb, high-fat diet promotes.
They also showed strong evidence that trans-fatty acids and foods with high glycaemic index or load (ie high-carbohydrate diets) as “harmful effects promoting CHD”. These are exactly the foods the Banting diet does not allow.
The study found insufficient evidence for: saturated and polyunsaturated fatty acids; total fat; alpha linolenic acid; meat; eggs; milk.
If my critics were steeped in the science as they claim, they could only have concluded in their letter to the media that my advice was compatible with the most rigorous science currently available. And that I’m correct to argue that there is no evidence that a high-fat diet causes anything.
Instead, they concocted an argument based on evidence that Bradford Hill would have rejected. And this from leading scholars at a leading medical institution in this country.
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