For decades, saturated fat has been demonized as a major cause of heart disease, obesity, and diabetes. However, the evidence supporting these claims is not as strong as it may seem. In this blog I explore why saturated fat has been unfairly targeted, and why carbohydrates may be the main culprits behind many modern health problems.
In 1980 in the US followed in 1983 by the UK, the first dietary guidelines were published with the main recommendation being to cut back on saturated fats and cholesterol. The public were swayed by this advice and replaced meat with pasta, and rice, butter with margarine and vegetable oils, and eggs with cereals. In reality we moved from eating saturated fat to eating carbohydrates and polyunsaturated fat, and instead of becoming healthier instead we ushered in an "obesity and chronic disease epidemic". Not my words but the words of the World Health Organisation who in 2022 said ‘none of the 53 countries that comprise its European region is on track to meet the agency’s non-communicable disease target of halting the rise of obesity by 2025.’ So what we have been doing has simply been making things worse and not better.
Nina Tiecholz, is a health journalist, who has probably investigated the fat myth more than anyone else, and wrote her research in the book ‘The Big Fat Surprise’. On her website she states that since her book was published in 2014 the data exonerating saturated fats has grown even stronger. “there are now more than 17 systematic reviews and meta-analyses of scientific studies looking at the relationship between saturated fats and heart disease. These studies include randomized, controlled clinical trials on more than 50,000 people, which is an enormous amount of the most rigorous kind of data available.” She concludes that by far the vast majority of studies have found that saturated fats have no effect on cardiovascular mortality and/or saturated fats are not associated with heart disease.
If we don’t want to take a journalist’s word for it then how about a cardiologists? Dr Aseem Malhotra in a 2016 article for the British Medical Journal wrote “Despite popular belief among doctors and the public, the conceptual model of dietary saturated fat clogging a pipe is just plain wrong.” He points out that in fact a chronically elevated serum insulin linked with insulin resistance was likely the root of heart disease, type 2 diabetes and obesity. Insulin resistance is mainly caused by too much dietary carbohydrate and you can read more about it in my blog on insulin resistance here.
A recent meta-analyses of studies from 2010 to 2021 published in December 2022 found that “that the consumption of SFA (saturated fat) is not significantly associated with CVD (cardiovascular disease) risk, events, or mortality. Based on the scientific evidence, there is no scientific ground to demonize SFA as a cause of CVD. SFA naturally occurring in nutrient-dense foods can be safely included in the diet.”
So why on earth has the official nutritional advice of many governments around the world, including the UK and US, been to continue to vilify fat? To answer this, we need to look back and learn from the events that led up to fats first being deemed bad for us.
The origins of the vilification of saturated fat can be traced back to the work of a physiologist called Ancel Keys. In the 1950s, Keys developed an idea that high blood cholesterol caused fatty deposits of a type thought to clog arteries and subsequently caused heart attacks. Based on his observations of diets eaten by people in European countries like Spain and Greece he had found those eating less saturated fat had less heart disease. He conducted a study known as the Seven Countries Study which helped develop his idea further and it became known as the diet-heart hypothesis. But Keys' work has been criticized for its selective use of data. In fact, a meta-analysis published in the American Journal of Clinical Nutrition in 2010 found that there was no significant evidence linking saturated fat intake to the risk of heart disease. He also declined to study countries such as France and Germany who were known to have a high saturated fat content to the diet but low levels of heart disease.
However, Key’s work was published in more than 20 papers between 1957 and 1958 and he was able to win over and influence key figures in the US which helped his idea to gain the advantage compared to other hypotheses and it became the dominant paradigm explaining cardiovascular disease for the next 70 years. One of these key players was Paul Dudley White, an influential cardiologist and the personal doctor to President Eisenhower. When Eisenhower suffered his first heart attack, Key was able to bring his ideas via White into the national spotlight. As their president was in hospital the US public became focused on what had caused the heart attack. Heart disease was still at that time a relatively new and terrifying condition. From being rare in the early 1900s I had risen by the 1950s to become the country's leading cause of death. White made it clear that diet was to blame and prescribed Eisenhower a diet low in cholesterol and saturated fats swapping butter for polyunsaturated margarine and eggs for toast for breakfast.
During the 1950s the American Heart Association (AHA) resisted giving advice on heart disease prevention stating a lack of evidence. But in 1960 Keys was appointed to the nutrition committee and within a year his diet-heart hypothesis had become official AHA policy. From then on it was recommended that everyone reduce their consumption of saturated fat and replace it with polyunsaturated vegetable oil. What is shocking is that the AHA had received a huge amount of money from Proctor & Gamble, the makers of the vegetable oil Crisco. Vegetable oil producers profited massively from this recommendation and perhaps helped sway the policy change.
What might surprise you is that alongside Key’s saturated fat hypothesis other researchers were thinking that carbohydrates were the more likely villain and could be blamed for many of the increasing health problems post-war in Europe. John Yudkin, a British nutritionist, was one of the first researchers to suggest that sugar, not saturated fat, was the real cause of heart disease. In his book "Pure, White, and Deadly," published in 1972, Yudkin argued that sugar consumption was linked to a wide range of health problems. However, Yudkin's ideas were largely ignored at the time, in part due to the influence of the sugar industry and other corporate interests. For example, The Sugar Bureau, a a UK industry-funded organisation set up in 1964 to improve 'knowledge and understanding about the contributions of sugar and other carbohydrates to a healthy balanced diet' dismissed his work “emotional assertions” and the World Sugar Research Organization called his book “science fiction.”
We should not underestimate the power that large corporations may have had in ensuring that fat and not sugar was the problem. Taking saturated fat out of food created a huge industry in itself to create low fat products. When fat is removed, sugar is generally added to make a product palatable and tasty. So not only does fat get reduced but the sugar content is increased.
A huge amount of ‘food’ that is in our supermarkets is now highly processed and the main reason for this is the huge development of technology in the 1940s to create time-insensitive food to feed military troops. Soldiers had to be catered for with rations which did not go rancid or mouldy and tasted as good as possible despite being transported to the other side of the world. This involved a huge industry of food scientists, food technologists, chemical engineers and packaging experts. A paper discussing how this huge change in food production described it as “highly processed foods needed a lot of work to make them taste either “natural” or even “scientifically delicious”—that is, utterly fake but oddly addictive.”
And the years following World War II continued to be very busy for the food industry. There were huge surpluses of cheap grain that led to the creation of convenience foods for the general population “many of which featured novel spray-on flavours, nutritional additives, and lots of salt, and fat. Foods formerly reserved for the military entered the civilian market in decidedly more stylish packaging.”
Although many studies had been done on saturated fat and heart disease many of these went unpublished partly due to the political pressure meaning that the scientists did not want to or could not get support for their ideas to be published. This was the case with the famous Framingham Heart Study, started in 1948 where detailed food-consumption data was collected from 1049 people. The results were calculated the results in 1960, and it was very clear that saturated fat was not related to heart disease. In summary the authors reported that ‘No relationship found’. But in 1992 one of the authors William Castelli publicly stated that in fact ‘In Framingham… the more saturated fat one ate … the lower the person's serum cholesterol… and [they] weighed the least”.
In Part Two next month I will take a look at what good metabolic health is, in terms of what blood and other tests you might want to look at, more detail about your blood fats - triglycerides and ‘good’ and ‘bad’ cholesterol, and the impact a low carbohydrate diet has on all of it.
If you want to use fat as a fuel to help address a chronic disease, help you drop a few pounds or get more energy then you can download my Quick Start Keto Guide For Fatigue (but it will help do the rest too!) https://www.moiranewiss.co.uk/quick-start-keto-guide-for-fatigue
Disclaimer: Before changing your diet or lifestyle and taking any supplements always seek the advice of your doctor or another suitably qualified professional such as a nutritional therapist. The content of this blog is for informational purposes only and is not a substitute for professional medical advice. Always seek the advice of your doctor with regards to any questions you have about a medical condition.