What’s the deal with fat? Is it good or is it bad? Are different types better than others?
There is so much conflicting information!
Let’s start with a history lesson.
For over forty years, society has held the belief that fat is bad, especially saturated fat and animal-derived fat. The belief has been that if you eat fat, it will clog your blood vessels, much like pouring fat down the drain can clog the drain. From a distance, this analogy seems rational enough, however that is not how human physiology works.
Where did this idea come from? I will go into greater detail about the history in future posts, but a big piece of the fat debate started in the 1950s when US President Dwight Eisenhower suffered a heart attack (1). At the time, heart disease was affecting more and more middle-aged men, and the public was searching for answers.
Ancel Keys, a nutritionist in the United States, had a theory. He believed that excess saturated fats in the diet, from red meat, cheese, butter, and eggs, raise cholesterol, which then congeals in blood vessels and cause them to narrow (1). Much like the clogged pipe analogy above.
Around the same time, John Yudkin, a scientist in the United Kingdom, found a correlation between the over-consumption of sugar, not fat, and coronary artery disease. He explained his findings by saying that we as humans have been eating animal-based fats for centuries, but sugar had been a very rare commodity up until the 1850s. Yudkin believed that it was the recent innovation of refined sugar, not the “prehistoric staple” of animal fats that were contributing to this modern disease (1,2,3).
Between these two scientists, Ancel Keys was the more vocal salesman and used many bullying tactics to convince the world that he was right. He used a great deal of name-calling and character assassinations, while John Yudkin did not respond similarly. Yudkin was a “mild-mannered man, unskilled in the art of political combat”. (1,2)
The food industry glommed on to Keys’ working theory of saturated fat causing heart disease, and began creating countless low-fat products to help the public “stay healthy”.
Unfortunately, as soon as fat is removed from a food item, it tastes like cardboard. In order to maintain a level of palatability, sugar needs to be added. This approach, of course, goes against Yudkin’s sugar findings, and The British Sugar Bureau and the World Sugar Research Organization went to all lengths to push Yudkin out of the picture. “The industry successfully discredited the case against sugar and his warnings were no longer taken seriously” (3)
During this time, Ancel Keys gathered data for a project called the Seven Countries Study (SCS), from 1958 to 1964. The study was published in 1978 and claimed that high cholesterol is the cause of heart disease and that saturated fat consumption from foods such as butter, cheese, and meats was correlated.
However, in 1987, Ancel Keys reviewed his study and told the New York Times that “I’ve come to think that cholesterol is not as important as we used to think it was” (3). The SCS lead Italian researcher, Alessandro Menotti, went back to the data and found that food which correlated most closely with deaths from heart disease was not saturated fat, but sugar, as John Yudkin had claimed (1,7). The SCS white paper acknowledged that it “never concluded that total fat intake should be restricted” (4)
Alessandro Menotti went back to the data and found that food which correlated most closely with deaths from heart disease was not saturated fat, but sugar, as John Yudkin had claimed (1,7)
The food industry, however, had already created a multi-million-dollar profit from the creation of low-fat food products. The US government had already created its first-ever Dietary Guidelines in 1980 that restricted the consumption of saturated fats and cholesterol (1). From an economic standpoint, It was too late to go back.
More and more studies, however, continue to demonstrate little or no association between saturated fat and mortality. In 1993 the Women’s Health Initiative found that women on a low-fat diet were no less likely than the control group to contract cancer or heart disease. In 2008 researchers from Oxford University found an inverse correlation between saturated fat and heart disease across Europe. British researcher Zoe Harcombe found that lower cholesterol correlated with higher rates of death from heart disease (1). A recently published PURE study found that high carbohydrate intake was associated with higher risk of total mortality, whereas higher fat intake was related to lower total mortality; and saturated fat had an inverse association with stroke. The authors concluded that “Global dietary guidelines should be reconsidered in light of these findings” (5). There are so many more studies to list, but these are some of the significant studies to date to give you an idea.
We cut out the saturated fat that Ancel Keys had initially claimed was the culprit. Should heart disease then be no longer an issue? Now that we have a food industry based on low fat and high sugar products, we have epidemic-level rates of obesity and diabetes. We are now seeing metabolic diseases like type 2 diabetes, an issue originally only seen in older adults, developing in children.
I have only provided a snapshot of the history and politics of the fat debate. However, these are the most important main points to understand where the belief came from that “saturated fats are bad”.
To replace these saturated fats in the diet, the food industry began producing more and more margarine and vegetable and seed-based oils. Because they came from vegetable sources, and they contain predominantly more polyunsaturated than saturated fatty acids, it has been believed that these are the “good” fats, while saturated fats are the “bad” fats.
However, these claims, in my opinion, could not be further from the truth. I’m not the only one saying this. Here is one example of many experts that are working to change the tides.
In part 2, I will explain the science behind polyunsaturated vegetable based oils, and how they affect the body. When all of this information is put together, then you can better decide which fat is actually the “good fat” and which one is best to avoid.
- Leslie, I. The sugar Conspiracy. Apr 2016. https://www.theguardian.com/society/2016/apr/07/the-sugar-conspiracy-robert-lustig-john-yudkin
- Smith, J. L. John Yudkin: the man who tried to warn us about sugar. Feb 2017. http://www.telegraph.co.uk/lifestyle/wellbeing/diet/10634081/John-Yudkin-the-man-who-tried-to-warn-us-about-sugar.html
- Malhotra, A. The fight against dietary misinformation continues. Jan 2018. http://www.menshealth.co.uk/food-nutrition/the-fight-against-dietary-misinformation-continues
- Harcombe, Z. The Seven Countries Study Part 1. Aug 2017. http://www.zoeharcombe.com/2017/08/the-seven-countries-study-part-1/
- Dehghan, MahshidDiaz, R et al. Associations of fats and carbohydrate intake with cardiovascular disease and mortality in 18 countries from five continents (PURE): a prospective cohort study. The Lancet. 390(10107): 2050-2062, 2017. http://dx.doi.org/10.1016/S0140-6736(17)32252-3
- Kresser C. New study puts final nail in the “saturated fat causes heart disease” coffin. Jan 2010. https://chriskresser.com/new-study-puts-final-nail-in-the-saturated-fat-causes-heart-disease-coffin/
- Teicholz N. The Big Fat Surprise: Why Butter, Meat and Cheese Belong in a Healthy Diet. Simon and Shuster, 2014.