The low-fat mantra all started in the 1950s with a scientist named Ancel Keys. He performed a couple of highly flawed studies where he "cherry-picked" data to show that saturuated fat intake caused heart disease. The government and food industry locked onto this idea, despite data and numerous studies that have flooded in to debunk this theory. I highly recommend the books Eat Fat Get Thin by Mark Hyman, MD, and Why We Get Fat by Gary Taubes, for more information and citations of this.
Here are 5 reasons that saturated fats are not going to increase your risk for heart disease or death:
1. Low-fat diets are NOT effective at preventing heart disease
No study has been able to prove that a low fat diet will decrease risk of cardiovascular mortality. Plenty of studies show that saturated fat can increase total cholesterol, and then make the simplified conclusion that saturated fats lead to heart disease. But this is highly misleading because yes, saturated fat will increase total cholesterol because it increases HDL cholesterol (good cholesterol), as well as the good type of LDL cholesterol (more on this below); however, no study can show a direct link between saturated fat intake and cardiovascular related death. Again, there are more studies then I could ever reference, but here are a couple good ones:
In 2010, an analysis of 21 quality studies that looked at roughly 350,000 individuals up to a 21 year period found no risk of saturated fat intake with cardiovascular disease or stroke
And lastly, one of the largest and most expensive and long term clinical trials called the Women’s Health Inititiative(WHI) was meant to show the benefit of a low-fat diet for lowering cholesterol and heart disease. After eight yearsof this study, the women on low-fat diet had lowered their total and LDL cholesterol, however, there was no beneficial effect on heart disease, stroke, or cancer found from eating a low fat diet.
2. Fat increases your HDL cholesterol (good cholesterol)
Low HDL cholesterol has been found to be a far greater risk factor of having a heart attack than a high LDL cholesterol . When you replace fat in your diet (including saturated fat), with carbohydrate, this lowers your HDL cholesterol. A study by The New England Journal of Medicine explains that a low HDL cholesterol is a “biomarker for dietary carbohydrate.” Saturated fats have been shown to increase your HDL cholesterol (good cholesterol), and to have either no effect on your triglyceride cholesterol or to reduce this (another type of bad cholesterol).
In practice, when I get a patient's labs back and I see a low HDL cholesterol level with high triglycerides, this is an indicator to me that this individual is eating a high carb, low fat diet.
3. Fat increases large LDL particles (good type) and decrease small LDL particles (bad type)
Yes, to make things more confusing there are different types of LDL, large "fluffy" type (think cotton balls), small dense type (think rocks), and many other sizes in between. We want more of the large LDL particles to small dense LDL particles because the small dense LDL particles are much easier to lodge themselves into the walls of your arteries causing your arteries to narrow which leads to decreased blood flow (ie oxygen to your heart). These small dense LDL particles also are known to oxidize which leads to rancidity and inflammation in the blood vessels. Saturated fats will increase large LDL and decrease small LDL which in effect will cut your risk of heart disease.
4. Replacing saturated fats with carbohydrates increases bad cholesterol
This is more of a summary of the above, but I want to reiterate that replacing saturated fats for carbohydrates makes your cholesterol profile much worse. Carbohydrates have been shown to decrease your good HDL cholesterol while increasing small particle LDL bad cholesterol, as well as inceasing your triglyceride cholesterol. As mentioned above, heart disease is most associated with a low HDL cholesterol and high triglyceride cholesterol. LDL is a little harder to predict with heart disease because of the varying sizes and conflicting evidence.
5. Prevents "Diabesity"
Cutting back on fat almost enevitably means you are going to add carbohydrates to your diet, and high carbohydrate intake is what leads to diabetes as well as obesity - this is something that is not disputed. Obesity is a risk factor in itself for heart disease, as is diabetes, put these two major risk factos together and you are talking about a massive increase in your chance of cardiovascular disease (think heart attack).
Just as guidelines have changed in terms of cholesterol containing foods (in case you didn’t know, cholesterol containing foods do not raise bad cholesterol and this has finally been recognized by the American Heart Association (AHA) and the United States Department of Agriculture (USDA)) I have a hunch that there will be new guidelines for saturated fats in the near future.
Be sure to increase your intake of good saturated fats such as organic eggs, organic grass-fed beef, coconut oil, and dark chocolate.
Sarah-Kate Rems, NP
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