 We've known for nearly a half century, according to 200 of the country's leading experts in cardiovascular diseases in our report representing 29 national medical organizations, including the American Heart Association, the American College of Cardiology, that coconut oil is one of the most potent agents for elevating the level of cholesterol in the blood. Studies showing coconut oil elevates cholesterol date back to 1955, when it was first shown experimentally that switching someone from coconut oil to something like soybean oil could drop cholesterol from like 200 down to 150. Coconut oil can significantly raise cholesterol levels within hours of consumption, a significantly increased blood cholesterol within hours of eating a slice of cake made from coconut oil or from cod liver oil for that matter. But not from the same cake made from flaxseed oil. Coconut oil may even be worse than tallow or beef fat, but not as bad as butter. The latest interventional trial was published March 2017, a month-long randomized controlled crossover study looking at the impact of two tablespoons a day of virgin coconut oil, and it elevated cholesterol about 14% over control. Consistent with the other seven interventional trials published to date in this 2016 review. But wait, saturated fats can make so-called good cholesterol HDL go up. So what's the problem? The problem is that doesn't seem to help. Having a high blood HDL level is no longer regarded as protective. What? But wait a second, higher HDL is clearly associated with lower risk of heart disease. In fact, HDL levels are among the most consistent and robust predictors of cardiovascular disease risk. Ah, but see, there are two types of risk factors, causal and non-causal. Association does not mean causation, meaning that just because two things are tightly linked doesn't mean one causes the other. Let me give you an example. I bet that the number of ashtrays someone owns is an excellent predictor of lung cancer risk. I bet study after study would show that link, but that doesn't mean that if you intervene and lower the number of ashtrays, their lung cancer risk would drop, because it's not the ashtrays that were causing the cancer, it was the smoking. The ashtrays were just a marker of smoking, an indicator of smoking, as opposed to playing a causal role in the disease. So just like having a high number of running shoes and gym shorts might predict a lower risk of heart attack, having a high HDL predicts a lower risk of heart attack, but raising HDL just like raising the number of gym shorts wouldn't necessarily affect disease risk. How do you differentiate between causal and non-causal risk factors? You put it to the test. The reason we know LDL, cholesterol, really is bad is because people who are just born with genetically low LDL end up having a low risk of heart disease, and if you intervene and actively lower people's LDL through diet or drugs, their heart disease risk drops. Not so with HDL. People who live their whole lives with high HDL levels don't appear to have a lower risk of heart attack, and if you give people a drug that increases their HDL, it doesn't work. That's why we used to give people high dose niacin to raise their HDL, but it's time to face the facts. The lack of benefit to raising HDL seriously undermines the concept of HDL being a causal risk factor. In simple terms, high HDL may not protect the heart. We should concentrate on lowering LDL. And so specifically as this relates to coconut oil, the increase in HDL is of uncertain clinical significance, but the increase in LDL cholesterol you get from eating coconut oil would be expected to have an adverse effect on atherosclerotic cardiovascular disease risk. But what about the MCTs? Proponents of coconut oil, who lamented that this whole coconut oil causes heart disease thing, has created this bad image for their national exports, assert that the medium chain triglycerides, the shorter saturated fats found in coconut oil, aren't as bad as the longer chain saturated fats in meat and dairy. And what about that study that purported to show low rates of heart disease among Pacific Islanders who ate tons of coconuts? I'll cover both these topics next.