Obesity? Forget the fats, it’s the carbs, stupid, says cardiologist


What does obesity have to do with hearts? Lots. Icelandic cardiologist Dr Axel Sigurdsson spoke recently at a meeting mostly of cardiologists and endocrinologists.

Dr Axel Sigurdsson

He discussed, among others, the current status of diet-heart hypothesis that saturated fat causes heart disease. And the possible relationship between fear of dietary fats and the obesity epidemic.

After the meeting, a senior colleague, an old friend and mentor,  lambasted him privately. He said that the mortality from heart disease had dropped dramatically for the last 30 to 40 years, mostly from dietary changes to lower blood cholesterol. 

He was angry that Sigurdsson suggested that the emphasis on low-fat food products ultimately had steered people into an epidemic of obesity, metabolic syndrome and diabetes. Here, Sigurdsson explains how and why low-fat diets contribute to obesity and a whole lot more. – MARIKA SBOROS

By Axel Sigurdsson

During (my discussion with my mentor), I came to think of Dr Tim Noakes’s words at the Foodloose Convention in Reykjavik last year. He touched upon the same issue. I had the privilege to speak at the same conference. It gave me the opportunity to meet and talk with Tim for the first time.

Tim showed the slide (left)  and said:

‘… the dietary guidelines changed in 1977 and in 1978 the obesity epidemic begins in the United States, and no one will take responsibility for that. And that’s the question you have to ask.

‘You change the guidelines and why won’t you take responsibility for what happened? Why do you ignore it? And, why do you attack us for asking that question?’

Yes, these were the words I remembered so vividly: … ‘and, why do you attack us for asking that question?’

Sixty years ago, American psychologist Leon Festinger described a phenomenon he called cognitive dissonance.   He believed that we hold many cognitions about the world and ourselves. When they clash, it evokes a discrepancy, resulting in a state of tension known as cognitive dissonance.

Our powerful motive to maintain cognitive consistency can give rise to irrational and sometimes maladaptive behavior.

Cognitive dissonance

Festinger wrote:

‘A man with a conviction is a hard man to change. Tell him you disagree and he turns away. Show him facts or figures and he questions your sources. Appeal to logic and he fails to see your point. ‘

Well, I guess you’re assuming that I think my senior colleague and old mentor suffers from cognitive dissonance. And you’re right, I do. But, I also know he thinks I’ve completely gone off the rails.

So, how can a low-fat diet lead to an epidemic of obesity, metabolic syndrome, and diabetes?

Let’s start by looking at three facts.

The first one is that a low-fat diet is also a high-carb diet. Of course, this does not imply that it is a diet composed of added sugars and refined carbohydrates. However, the energy has to come from somewhere and therefore a low-fat diet is usually synonymous with a high-carb diet.



The second fact is that according to recently published evidence, at least 50% of the adult population in the US has insulin resistance. It manifests as diabetes or prediabetes.

The role of insulin resistance

Finally, there is evidence from several studies on human metabolism showing that insulin resistance and high-carb diets make a destructive combination. And, remember, at least half of the U.S population is insulin resistant.

Let’s quote Tim Noakes’ Reykjavik lecture again:

‘Insulin resistance is a benign condition. However, a high carbohydrate diet turns it into a killer.’

Noakes believes that the macronutrient of interest in chronic disease is carbohydrate, not fat:  

‘They completely got it wrong. Ancel Keys backed the wrong horse completely. But, this truth comes through understanding human metabolism, not epidemiology.’

Insulin resistance is defined as a diminished response to a given concentration of insulin. Initially, the pancreas responds by producing more insulin (compensatory hyperinsulinemia). For this reason, individuals with insulin resistance often have high levels of insulin in their blood.

Gerald Reaven is professor emeritus in medicine at the Stanford University School of Medicine. He was the first to emphasise the role of insulin resistance and compensatory hyperinsulinemia in increasing the likelihood of developing the cluster of abnormalities commonly referred to as the metabolic syndrome.

Metabolic syndrome

The five conditions described below are used to define the metabolic syndrome. Three of them must be present in order to be diagnosed with the condition.

  • Abdominal obesity, defined as waist circumference > 40 inches (102 cm) in men and > 35 inches (88 cm) in women
  • A high triglyceride level in blood, defined as > 150 mg/dL (1.7 mmol/L)
  • A low HDL cholesterol level in blood, defined as < 40 mg/dL (1 mmol/L)
  • High blood pressure, defined as > 130/85 mmHg or drug treatment for elevated blood pressure
  • Elevated blood sugar, defined as fasting blood glucose >100 mg/dL (5.6 mo/L) or drug treatment for diabetes

In his Reykjavik lecture, Tim Noakes summarised a few Reaven’s studies on the importance of triglycerides in patients with insulin resistance.


Dangers of high-carb diets

In a study published 1966, Reaven and colleagues examined the triglyceride response to low- and high-carbohydrate diets. They discovered that the majority of patients will increase their triglyceride concentration to a variable extent as a consequence of a high-carb diet.

Interestingly, they also found that the more insulin resistance present, the greater the subsequent rise in triglycerides following the ingestion of carbohydrates.

Reaven also suggested that the liver’s increased triglyceride production causes endogenous hypertriglyceridemia. In other words, the liver is pumping triglycerides into the circulation. The higher the plasma insulin, the higher the liver production of triglycerides, the higher the blood levels of triglycerides.

Endogenous hypertriglyceridemia, which includes familial hypertriglyceridemia and idiopathic hypertriglyceridemia, is characterized by the increased level of very low-density lipoprotein (VLDL) and triglycerides in the blood.

Hence, insulin resistance, accompanied by hyperinsulinemia, may be an important cause of the enhanced triglyceride production by the liver following the ingestion of a diet high in carbohydrates.

The real cause of heart disease?

Reaven developed a model explaining the relationship between insulin resistance and cardiovascular disease. He concluded that insulin resistance and hyperinsulinemia are common findings in apparently healthy individuals and associated with a number of abnormalities that significantly increase the risk of coronary artery disease.

Among them are lipid abnormalities commonly termed atherogenic dyslipidemia because they tend to promote atherosclerosis. Scientists believe that to be the underlying cause of cardiovascular disease.

Several bad things seem to happen if we’re insulin resistant. These include weight gain, atherogenic dyslipidemia, visceral adiposity hypertension (high blood pressure), systemic inflammation, mitochondrial dysfunction, and impaired exercise performance.

Noakes believes that Reaven’s biggest mistake was not to pinpoint high-carbohydrate diets as the culprit. However, Noakes refers to three papers published by Reaven’s group between 1987-1994. This emphasises that Raven knew that carbohydrate was the villain.


Benefits of lowering carb intake

Noakes says:

‘So, Reaven understood that carbohydrates drive insulin secretion in the metabolic syndrome. Hence, he had to conclude that restricting carbohydrate should be the key therapy for this condition. In 1987, he was heading into that conclusion because he published three papers in 1987, 1989 and 1994 all showing the benefits of low carbohydrate diets in people with insulin resistance.’

The studies Noakes is referring to were performed on individuals with non-insulin dependent diabetes mellitus (NIDDM). That group that is highly representative for insulin resistance. Here are Reaven’s main conclusions from these three papers:

‘These results document that low-fat, high-carbohydrate diets, containing moderate amounts of sucrose, similar in composition to the recommendation of the ADA, have deleterious metabolic effects when consumed by patients with NIDDM for 15 days. Until it can be shown that these untoward effects are evanescent and that long-term ingestion of similar diets will result in beneficial metabolic changes, it seems prudent to avoid the use of low-fat, high-carbohydrate diets containing moderate amounts of sucrose.

‘The results of this study indicate that high-carbohydrate diets lead to several changes in carbohydrate and lipid metabolism in patients with NIDDM that could lead to an increased risk of coronary artery disease, and that these effects persist for more than 6 weeks. Given these results, it seems reasonable to suggest that the routine recommendation of low-fat high-carbohydrate diets for patients with NIDDM be reconsidered.

‘In NIDDM patients, high-carbohydrate diets compared with high monounsaturated fat diets caused persistent deterioriation of glycemic control and accentuation of hyperisnulinemia, as well as increased plasma triglycerides and VLDL-cholesterol levels which may not be desirable.

Liver disease

Then Noakes says:

Why did he (Reaven) stop in 1994 doing low-carbohydrate studies? The answer is that because he was at Stanford, which is one of the most progressive cardiovascular groups. Had he come out in 1994 and said you must all eat a high-fat diet, his career would have ended overnight. And wisely he decided to continue researching without drawing attention to himself and that’s why that work is so fundamental but it has got lost.’

Non-alcoholic fatty liver disease (NAFLD) has become the leading cause of chronic liver disease in the United States and other Western countries.

It is primarily triglycerides that accumulate in the liver in patients with NAFLD. Triglyceride accumulation may be due to an excessive importation of free fatty acids to the liver from adipose (fat) tissue. Excessive amounts of fatty acids may also be produced by the liver cells themselves due to an increased conversion of carbohydrates and proteins to triglycerides. Defective transport of fatty acids from the liver may also contribute to the accumulation of triglycerides in the liver.

A paper published 2016 suggests that the presence of NAFLD in people with insulin resistance is a key driver of atherogenic dyslipidemia so typical of the metabolic syndrome.

Patients with NAFLD are more likely to have high levels of apolipoprotein B and small LDL particles, regardless of similar body mass index and other clinical parameters. The authors speculate that this lipoprotein profile is driven mostly by liver fat content and insulin resistance and appears not to be worsened by obesity or the severity of liver disease. Hence, NAFLD may be a major link between insulin resistance, metabolic syndrome, and coronary heart disease.

Key driver

In his Reykjavik lecture, Noakes said:

What they are showing for the first time is that the key driver of atherogenic dyslipidemia is NAFLD. And, how do you get NAFLD?  You get it from eating a high- carbohydrate diet feeding insulin resistance.

Noakes does an excellent job in explaining the clinical implications of the metabolic abnormalities underlying insulin resistance, visceral obesity, type 2 diabetes, and coronary heart disease, and how these may be fueled by high consumption of carbohydrates.

You’re either highly carbohydrate tolerant, normal or carbohydrate intolerant. If you’re tolerant, you’re probably an athlete, probably not overweight or obese, and you’ll probably not get these diseases, and you can eat pretty much what you like.

But if you’re carbohydrate intolerant, there’s only one way you can go; insulin resistance, expanding waistline, obesity, metabolic syndrome and type 2 diabetes await you.

Noakes says:

And that’s the point when we’re talking about nutrition. Nutrition is not the issue. It’s the patient. And you’ve got to fit the diet the patient. People just don’t seem to get  that if you’re insulin resistant you cannot eat carbohydrates.

Noakes is convinced that a low-carbohydrate diet is a key to the prevention and treatment of insulin resistance and all its associated conditions.

Low-fat ‘catastrophe’?

If he’s right, advising everybody to consume a low-fat, high-carbohydrate may be catastrophic because at least 50% of the adult population is insulin resistant. If we put all these insulin resistant people on a high-carb diet, we may have an epidemic of obesity, metabolic syndrome and type 2 diabetes.

Sounds familiar huh?



  1. There is no doubt in my mind that terribly mis-handled STRESS was at the ….heart… of my rapidly occluding coronary arteries, “requiring” a 5 way CABG. This was despite remaining close to ideal weight, a low carb eating pattern and average glycemic control. It took 14 months…

  2. TeeDee, It is reliably reported by one of his (at his Italian residence) Housekeepers, that he did not always follow his own dietary advice. – What a Surprise !

  3. At some time in the future, a paradigm shift on diets will occur. When this happens will we be able to sue our health practitioners for giving us wrong and deadly advice?

  4. Brilliant stuff as always. So SAD (pun intended) that the likes of Reaven and the late Joseph Kraft did so much work and yet are still largely ignored. Meanwhile dieticians and others in the pay of the Foodlike Substance Manufacturing Industry are orchestrating a fightback: http://www.medscape.com/viewarticle/881689. When David Katz is involved you just know it isn’t going to end well.

  5. Thanks so much for this, Marika. I’m just going to have to accept the fact that reading these articles is going to make me feel both angry and happy at the same time. Angry that this information was kept from us for decades, leading to myriad chronic illness, and of course, happiness at finally being told the truth by rebels like you, Tim Noakes and a growing number of others. 🙂

    • I know just what you mean. I was stunned when I realised the depth of suppression of the evidence. I thought I was un-stunnable. I had no choice but to begin this remarkable journey uncovering the who, what, when, where, why and how of that suppression. It’s a very murky story. Thank you for your comments on social media!

  6. Excellent article.

    Isn’t sugar consumption a major contributor to NAFLD? Sugar is 50% fructose and 50% glucose. We’re not designed to deal with much fructose, certainly not over a prolonged period. Now so much food is packed with sugar, often after removing the fat, that our bodies struggle to cope with it. Unless rapidly used, the fructose is stored as liver fat and this leads to insulin resistance and type 2 diabetes.

  7. Thanks for this Marika and… As always, a clear and well argumented viewpoint from Axel Sigurdsson. His Tim Noakes quote hits the nail on the head:
    The macronutrient of interest in chronic disease is carbohydrate, not fat. “They completely got it wrong. Ancel Keys backed the wrong horse completely. But, this truth comes through understanding human metabolism, not epidemiology.”
    It is strange to look back and see how epidmiologists won over the majority scientific viewpoint in spite of common sense, the French paradox, the basic laws of human metabolism and much more. They have a lot to answer for as NAFLD, T2DM and all the other effects of Insulin Resistance take over the waiting rooms of doctors and A&E departments around the world.

    • An Oceanographer that specialize in eels, named Ancel Keys back in the 1950s and 1960s, put out a LOT of misleading, even dishonest, public statements claiming low fat diets would prevent heart disease. Since then, scientist have been trying to prove that eating animal fat causes disease. So far, they have only been able to prove that rabbits that are force fed animal fat, get heart disease. Keys studies never included a diet composed of actual foods rich in saturated fat, instead he used trans fats. It may be a coincidence but before Ancel Keys phony ideas, and before the insane corn oil craze, we didn’t have all this chronic disease and obesity.

      • Common sense and a bit of knowledge about rabbits, tells me the heart attack was brought on by stress. I knew someone who had a few rabbits as pets and if one of them ever got cornered by a cat, the stress of that situation (though the cat didn’t physically harm the rabbit) would most often kill it within 30 minutes. I’m not a medical researcher, but my money would be on the stress of being “force fed” animal fats/trans fats and not necessarily the fat itself. That said, while animal studies can point humans in the right direction as to study questions and design, we’re omnivores, not herbivores being force fed anything. Ancel Keyes seemed to be the type that hung on to his preconceived notions to the bitter end; unlike a truly dedicated scientist would.

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