By Marika Sboros
At the heart of the trial of scientist Prof Tim Noakes is the diet-heart hypothesis – that saturated fat causes heart disease. US investigative journalist Nina Teicholz focused on the hypothesis in her testimony in Noakes’ favour at the fourth session of the Health Professions Council of SA (HPCSA) hearing in Cape Town on October 25.
Teicholz showed how the creator of that hypothesis ignored evidence showing that sugar and others carbohydrate are far more likely causes of heart disease. Here, in Part 2 of a two-part series on her evidence, she shows why low-fat diets can be lethal. Teicholz also looks at the role of sugar in the rise of chronic diseases. She hows why people should go back to the way they used to eat before epidemics of obesity and diabetes took hold.
The HPCSA has charged Noakes with unprofessional conduct for giving unconventional advice to a breastfeeding mother on a social network (Twitter). That was for a tweet in which he said good first foods for infant weaning are low-carb, high-fat (LCHF). In other words, he was suggesting meat, full-fat dairy and vegetables.
Teicholz is author of The Big Fat Surprise, a groundbreaking book that experts internationally acknowledge as having changed the face of nutrition science. She based her evidence in chief at the hearing on the 10 years of research it took to write the book.
She told the hearing how US physiologist Ancel Benjamin Keys came up with the diet-heart hypothesis in the 1950s. To support it, he needed research. Keys embarked on the Seven Countries Study. Though fatally flawed, it was an “extremely influential”, study that is still well-cited.
“If you read 10,000 nutrition papers, as I’ve done, they all telescope back to Keys’ Seven Countries Study,” she said. It became the “Big Bang of modern nutrition studies”.
Study results showed exactly what Keys had hoped they would: that men who did not eat much saturated fats had lower rates of cardiovascular death. That was because Keys “cherry-picked” the countries that he included in the study, Teicholz said.
He avoided countries such as Switzerland, Germany and France, where he knew that people ate lots of saturated fat yet had low rates of heart disease, Teicholz said. These countries “would have ruined his findings on saturated fats”.
Click here to read Part 1 of this series: TEICHOLZ EXPLODES FAT BOMBS IN NOAKES TRIAL
Teicholz asked Keys’ right-hand man, Henry Blackburn, why Keys and colleagues did not go to those countries. Blackburn said Keys had “just a personal aversion to being in those countries”.
She presented other problems with the Seven Countries Study, which she has documented in detail in The Big Fat Surprise. These include data “inconsistencies” which Keys could not resolve.
One error is “emblematic”: The men Keys studied on the island of Crete became the foundation for the Mediterranean diet as we know it today. Those men seemed to eat very little saturated fat and had very low rates of heart disease.
Yet of the three study periods that Keys spent collecting data on Crete, one fell during the month of Lent. That was when the islanders would have been religiously avoiding all meat, dairy, eggs and even fish.
“The Greek orthodox fast is a strict one,” Teicholz said. Thus, Keys must have undercounted the amount of saturated fat the Cretans ate, she said. Keys knew of this problem but dismissed it without explanation.
One of Keys’ fellow project leaders, Alessandro Menotti, headed up the Italian part of the Seven Countries Study.
Much later, in 1999, Menotti went back to re-analyse the dietary data. He found that the food that best correlated with heart disease was not saturated fats, but “sweets”, Teicholz said.
She asked Menotti how that finding escaped Keys. He told her that the Seven Countries Study leaders “did not know how to treat (sugar). We reported the facts and had some difficulty explanation our findings.”
Teicholz said Keys clearly knew that the hypothesis that sugar causes heart disease competed with his own. He also knew that only one could be right. He did what he had always done when dealing with inconvenient hypotheses: he went on the attack.
One of the most prominent proponents of the sugar hypothesis in the 1970s was Prof John Yudkin of Imperial College, London. Yudkin is author of Pure, White and Deadly – How Sugar Is Killing Us And What We Can Do To Stop It.
Keys dismissed Yudkin’s theory as “a mountain of nonsense”. He suggested that financial reasons motivated all those who promoted the idea that sugar caused heart disease. Or, he said, they were “just plain wrong”.
And while the Seven Countries Study was large and seemingly persuasive, it was still only observational. A basic principle of science remains that observational studies can only show association but not causation, Teicholz said. For causation, clinical trials are needed, preferably randomised controlled clinical trials that are “absolutely gold standard”.
Teicholz showed how governments around the world undertook randomised control clinical trials (RCTS) on the diet-heart hypothesis throughout the 1960s and 1970s. They used foods high in vegetable oils, such as margarine and soy-filled milk.
A previous expert witness for Noakes, British obesity research Dr Zoe Harcombe, reviewed much of those studies during her evidence-in-chief. So Teicholz did not go into those in detail. She referred briefly to research that included the Finnish Mental Health study that lasted for 12 years and studies the US National Institutes of Health (NIH) funded. Among these are the LA Veterans Study, the Minnesota Coronary Survey, and the MrFit Trial, as it is known.
The NIH alone spent billions of dollars on studies, trying – and failing – to prove Keys’ hypothesis, she said. These trials were “remarkably special” as they were highly controlled, in-patient environments where all meals were served.
Additionally, almost all these studies had “hard endpoints.” This means they had “indisputable outcomes,” such as death, which “ cannot be contested”. The diagnosis of a heart attack is another end point but “a little more disputable”, she said.
Many studies today use far less reliable “intermediary endpoints”. These include lipid markers such as LDL-C (low-density lipoprotein cholesterol) and HDL-C (high-density lipoprotein cholesterol). There is “quite a lot of dispute” over those, Teicholz said, in terms of which best predicts heart-attack risk.
Altogether, the trials on the diet-heart hypothesis included more than 75 000 subjects, mostly men but some women. They did show that restricting saturated fats reduced total cholesterol. However, there was no impact on the ultimate outcome – whether or not people died of a heart attack, she said.
In recent years, researchers around the world have gone back and looked at this data. There are now more than a dozen meta-analyses and systematic reviews published, Teicholz said. Nearly all have concluded that saturated fat and dietary cholesterol do not cause death from heart disease.
Low-fat diets are consistently shown to lower HDL-C (so-called “good cholesterol”). That means they actually increase the risk of heart disease.
Some official bodies are taking notice, Teicholz said. The Canadian Heart and Stroke Foundation (CHSF) – the equivalent of the AHA in the US and the Heart and Stroke Foundation of South Africa – has re-evaluated the data. In 2015, the CHSF lifted the cap (as a percentage of calories) on saturated fats, Teicholz said.
Although few people are aware of it, the US Dietary Guidelines for Americans also no longer recommend a low-fat diet, precisely because of compelling evidence that it causes heart disease, she said. But it’s also because clinical trials on more than 52,000 people show a low-fat diet to be “ineffective in fighting any other kind of chronic disease”.
Teicholz presented disturbing evidence to show that by 1981, for example, nearly 12 sizeable studies on humans found a link between lowering cholesterol and cancer. That was principally for colon cancer. Other research linked vegetable oil diets with an increased risk of lung cancer.
Teicholz cited an analysis Noakes has done of the US Women’s Health Initiative (WHI) study on nearly 49 000 women over seven years. His study found that those women with the least insulin resistance at the start of the trial actually had a greater risk of developing type 2 diabetes if they were eating the low-fat diet, compared to the control diet.
The low-fat diet also worsened glucose control in women with diagnosed diabetes.
Both these markers imply that the low-fat diet increased the risk for diabetes, compared to the control group eating a higher-fat diet, she said. WHI authors concluded that health professionals should exercise caution in advising women with diabetes to reduce dietary fat “unless accompanied by additional recommendations to guide carbohydrate intake”.
In other words, said Teicholz, the advice was that “women should be careful about eating so many carbs because a low-fat diet was, by definition, a high-carb diet”.
Teicholz told the hearing: “Thus, it’s fair to say that many RCTs on the diet-heart hypothesis found no evidence of benefit and some evidence of harm.”
The diet-heart hypothesis has been “the most tested hypothesis in the history of nutrition and disease”, she said. “And the results were null.”
She presented the competing carbohydrate-insulin hypothesis of obesity. Evidence to support it includes;
- More than 74 randomised controlled trials, virtually all on Western populations
- At least 32 trials of low-carb diets have lasted six months or longer
- Three lasted two years (the gold standard) to see any adverse side effects.
These trials have established that low-carb diets are safe, she said. They have also established efficacy for fighting obesity, diabetes, and heart disease (improves nearly all CVD risk factors).
Click here to read: KETO POWER – DISPELLING MYTHS OF LCHF DIETS
From there, Teicholz turned to the politics of nutrition science. She said it is needed to explain why so many people in positions of power and authority have been able simply to ignore all the evidence that did not suit their favoured hypothesis.
“We know that the food industry is large and powerful and plays a role in our nutrition policy,” Teicholz said.
She interviewed hundreds of executives for The Big Fat Surprise and came to realise just how profoundly the food industry has affected and continues to affect science.
The industry started financing nutrition science back in the early 1940s, she said. The then-emerging manufactured food industry understood early on that by far the most effective way to influence policy was to fund science at its very source – scientists, university chairs, etc.
And of course, the low-fat, high-carb industries have vested interest in maintaining the diet-heart hypothesis as status quo.
.@CarynZinn Phytates in grains bind w/ iron, B Vits and excrete them from the body. So carbs for babies actually reduce avail.of those vits.
— Nina Teicholz (@bigfatsurprise) October 26, 2016
All the carbohydrate companies who produce cookies, crackers, chips, serials, grains, rice, all those companies benefit from the reduction in fat, she said. She presented evidence on the “brilliant” way vegetable oil companies promoted their products as “health foods”. They touted them as ways to reduce cholesterol.
“They marketed these foods practically as pharmaceuticals,” said Teicholz.
That would not have been possible had the diet-heart hypothesis not become powerfully enshrined in the US Dietary Guidelines.
These guidelines are “enormously influential”, she said. Doctors, nutritionists and dieticians have followed them “like the bible, with a kind of kind of religious faith”.
Saturated fat “phobia” has been part of that faith.
Conflicts of interest (with Coke, eg) compromise US public health agency’s mission, say scientists | The BMJ https://t.co/serIWJ4GPE
— Nina Teicholz (@bigfatsurprise) October 28, 2016
Yet fat “is an important element in any manufacture of foods”, Teicholz told the hearing. Fat conveys flavour and enables texture. It is “an essential ingredient in many foods”.
When you take fat out of a food item, you have to replace it with something. That something is what the industry calls “fat replacers”. Industry uses the replaces in low-fat foods, such as low-fat yogurt, peanut butter and salad dressings.
“Fat replacers are almost all carbohydrate-based. Often, they are just sugar,” said Teicholz. “If you lower fat, you increase carbohydrates. Low-fat foods are almost inevitably higher in carbohydrates. Low-fat yogurts, for instance, tend to have a much higher sugar content.”
Teicholz said the scientific jury was still out on whether some carbohydrates are worse than others, and whether whole grains are much better than refined carbohydrates, in terms of their impact on metabolic health.
“These questions are still unfolding. We do not know exactly why carbohydrates are now driving disease more than they did in the past. Nor do we know if it is some combination of total carbohydrates plus sugar that has an especially negative metabolic effect.”
“We also do not know if it is that we have changed the way we produce wheat, if it is something about food processing, or if it is vegetable oils plus carbohydrates that are provoking obesity and diabetes.
“We really do not know. All we do know is that if you restrict carbohydrates, you see benefit.”
Dietary guidelines claim to offer a range of diets. In the US these are: US-style, Mediterranean and vegetarian diets. However, these diets are really just a “one-size-fits-all”. She presented a comparison slide to explain why. (See right.)
Teicholz said the US dietary guidelines – and by implication, South Africa’s guidelines – should no longer be the “gold standard.”
The guidelines have hardly changed over the past 35 years, she said. So there’s no reason to expect different results. She referred to the definition of insanity: To do the same thing over and over and expect different results.”
As a way forward, Teicholz suggested two policy implications based on all the currently available evidence.
- Low-carb diets should be considered as a safe and effective option for people with metabolic conditions. There is no scientific reason to demonise fat or label low-carb diets as a “fad” or remotely dangerous, she said.
- As a general population-wide recommendation, it would be safe to “back out” of the high-carb diet and return to what we ate in 1965, before the epidemics of obesity and diabetes. That means less than 40% of calories as carbs and about 45% as fat.
An obstacle to progress, Teicholz told the hearing, is that vested interests still employ the tactics Keys used to silence and stifle scientific debate. What has been happening to Noakes is happening “around the world”: “What you see is people who are trying to present alternative views of the science and who are being punished for it.”
In the US, doctors and scientists have collected hundreds of scientists around the world to form a group called the True Health Initiative. Their motto is: “We agree.”
Teicholz clearly thinks little of that initiative and rightly so: “Their principle is that there should be no debate, that science is settled,” she said.
“But science is never settled.”