The notion that saturated fats have a detrimental effect on human health gained attention for the first time in 1950. The theory was promoted by Ancel Keys, a US nutritional scientist. Dr. Keys postulated a correlation between saturated fats, cholesterol levels, and cardiovascular disease and initiated a study to prove his hypothesis.

At a 1955 meeting of the World Health Organization in Geneva, Dr. Keys presented his diet-lipid-heart disease hypothesis. At that time in the USA, heart disease was on a steep rise, with no apparent cause. 

His presentation laid the ground work for other studies, many of them concluding that saturated fats do in fact raise cholesterol levels — specifically the “bad” LDL cholesterol. Indirectly, saturated fats, by increasing LDL cholesterol, were now listed as a risk factor of heart disease.

The Low Fat Diet Craze

What ensued was an anti-fat campaign that peaked in the 1980s and continues still today. Throughout the years, countless numbers of low fat or fat-substitute products were introduced in hopes of minimizing saturated fat consumption and subsequently lowering heart disease risk.

So has minimizing saturated fats for the last 60 or so years produced the expected outcome? In short, the answer is no. Heart disease remains our nation’s number one killer. But it’s not because the science is totally wrong. We just didn’t know the complete story.

The Complete Story of Saturated Fats and Cholesterol

Saturated fats raise LDL cholesterol. And that should be enough information to avoid them, as high LDL cholesterol is an independent risk factor of heart disease. 

But over the past two decades we’ve learned a great deal about LDL cholesterol. And what we’ve learned should vindicate saturated fats and bring them back to the dinner plate.

There are two basic types of LDL cholesterol. There’s the small, dense type that’s prone to clogging arteries and then there’s a larger, buyout type that is much less prone to cause clogs. 

It turns out that saturated fats raise the large, buyout, less artery clogging type of LDL cholesterol.¹ This was first confirmed in 1998, yet it remains largely unknown to most Americans.

Sugar is the Real Culprit

Simple sugars raise LDL cholesterol. But unlike saturated fats, sugar has its greatest influence on the small, dense type of LDL — increasing the risk of heart disease far greater than saturated fats ever could.

And this is why the low fat craze didn’t lower heart disease risk as expected. As we removed the fat, we added the sugar! The added sugar increased the artery clogging type of LDL cholesterol, and we saw a rise in heart disease cases, not a decrease.

Additionally, a high sugar diet increases the triglyceride level.² This is a measurement of fats in your blood. The higher it is the greater the risk of heart disease. We used to think saturated fats did this, but we were wrong. Once again, sugar is the culprit.

Putting it all Together

In correct proportions, saturated fats can be a component of a healthy diet. They don’t raise levels of the small, dense, and dangerous type LDL cholesterol, nor do they increase triglycerides to any significant degree. All of these are now attributed to simple sugars. 

By the way, saturated fats are important for healthy cells and cell membranes, maintaining balanced hormone levels, and supporting brain health. So go ahead, bring back the fat — just don’t overdo it!

Here are a few healthy saturated fat choices:

1. Avocados
2. Coconuts and coconut oil
3. Nuts and seeds
4. Organic, grass fed meats and dairy products
5. Unheated organic nut oils

References

1. Am J Clin Nutr. 1998 May;67(5):828-836.
2. Circulation. 98:935–939.