Lipid Hypothesis: measures used to lower the plasma lipids in patients with hyperlipidemia will lead to reductions in new events of coronary heart disease.
In other words, a link is posited such that consuming dietary fat leads to increased blood cholesterol levels; increased cholesterol levels lead to heart disease.
About 60 years ago, the government started telling us that saturated fat is bad for you. In particular, saturated fat raises “bad cholesterol,” otherwise known as Low-Density Lipoprotein (LDL), which by the way is not technically cholesterol. This bad cholesterol is sure, according to our dear government, to kill you in a most unpleasant way.
As Richard Feynman said, “if it doesn’t agree with reality, it’s wrong”. If the hypothesis is that saturated fat raises your triglycerides, raises your cholesterol, and increases the likelihood that you’ll die early, then the minute saturated fat doesn’t do that, it seriously throws the hypothesis into question. At the very least, when we see saturated fat not causing harm en masse, it should prompt us to ask the question, were we wrong? Indeed, the data proves the hypothesis is shit.
Why is it that a person who cuts carbs and significantly increases their saturated fat intake gets healthier and loses fat quicker than the traditional reduced calorie, high grain diet? Why is it that reduced carbs and increased saturated fat, on average, drastically reduces triglyceride levels? Why is it that SO MANY people are having a lot of success controlling blood sugar, weight, cholesterol, and triglycerides, even though they’re getting 50%+ of their diet from fat?
There is no mechanism I am aware of that could lead to increased LDL cholesterol from eating saturated fat; on the contrary, the only way to raise LDL, as far as I know, is by consuming excess carbohydrates. The way it works is that you overeat carbohydrates, the liver converts those excess carbohydrates to fat, the liver then packs said fat into a VLDL lipoprotein and sends it out to the bloodstream. The VLDL delivers the fat to fat cells, and voila, you’ve got LDL.
Saturated fat follows a similar looking trajectory, except, instead of being packed onto a VLDL, it gets loaded onto Chylomicrons. It also skips the liver – it enters the blood through the thoracic duct. The handoff between the lipoprotein and the fat cell looks similar to the excess fat released by the liver; however, the remaining chylomicron is shrunk down much smaller than LDL. In other words, saturated fat doesn’t raise your LDL level.
Aside from technical aspects of this mechanism, there are a few things that are clear, based on the disastrous consequences of the last 60 years of public health policy:
1. It is overwhelmingly harmful to rely on cohort surveys to drive health policy. Cohort surveys have a place in science and medicine, but should not be the only tool used to demonstrate something’s benefit or harm. Well-designed control trials are the only reliable tool to demonstrate causation
2. Saturated fat and cholesterol are not the problems the government and “health experts” have been making them out to be for the past 60 years. In fact, external (exogenous) cholesterol has negligible effects on blood cholesterol. Moreover, there is no biological mechanism for saturated fat to affect cholesterol levels
3. The success of various diets (veganism, paleo, ketogenic, traditional reduced calorie) makes it clear that sugar (sucrose), high fructose corn syrup, and processed flour are the primary problems. Vegetable oils with a high amount of omega 6 are probably a problem too
There are plenty of people who articulate this better than me, but I think the takeaway of our observations in reality should be that the fixation on the relationship between saturated fat and blood cholesterol should be critically re-examined. Better alternatives, based on best practices, should be favored over dogma and demonization.