I feel that, with Cholesterol being such a big subject, I have to stress that I am not a doctor. So here it is: I Am Not A Doctor... nor a nutritionist... or a lipidologist.

Now that's out of the way let's discuss cholesterol.

Franki and I recorded a video recently about it. The aim was not to be too scientific. There are plenty of much better websites explaining this matter. For example, I cannot stress enough that you guys should go and see Dave Feldman's blog Cholesterol Code
No, our aim is to try to be a first stop, to add to the argument or to the voice that what we know about cholesterol is wrong. So after you watching our video or reading this page, if you want to know more you will know where to start.
Here's the video.
If you can't watch it, I leave my notes from the episode below. In fact you may want to read them anyway because I think they make much more sense than our rambling. And I may or may not be entirely correct in all aspects, like dates and names.

What is cholesterol?

Cholesterol is a lipid or a fat.
Almost all cells can produce cholesterol with the liver being the organ that produces the most. Cholesterol actually protects our cells by acting as a shield.

You have probably heard of LDL and HDL, often referred to as bad and good cholesterol.
These are actually lipoproteins and they are transporters. They transport cholesterol, triglycerides and fat soluble vitamins. You most likely know that fats are hydrophobic, as in they are not water soluble, quite the opposite of sugar in fact. So the body has a clever way to transport triglycerides, certain vitamins and cholesterol through the body. They leave the liver in Low Dense Lipoproteins, big ships travelling through the bloodstream.

The cholesterol test was invented/discovered in the mid 1930s. It measured total cholesterol. This is the same test still being used today as it's cheap and easy.

Why do we fear cholesterol? How did cholesterol get the blame?

Part of cholesterol's job is to protect cells. So if there's any damage, cholesterol is sent to protect it giving the body a chance to repair it.
Back in the 20th century, heard disease was becoming a major concern. In fact you could say it was the epidemy of that century in the same way diabetes is for the 21st.
The interesting thing is that arteriosclerosis was rare before 1930s. But from the 40s and 50s, after the test was invented and other advances in medicine, doctors noticed a plaque becoming commonly present in the arteries. As such, many convinced themselves that cholesterol, which formed the plaque, was in fact the cause of heart disease.
One of this doctors was Ansel Keys.
This is where things start to not make sense.

  1. Why blaming a new disease on an old food like fat, saturated fats? Butter and lard have been used for millennia.
  2. Other factors could have been contributing to this increase in plaque. Few noticed that both sugar and tobacco consumption were starting increasing at a rapid pace.
  3. There were no concrete studies showing cholesterol as being the cause, or that dietary cholesterol, the one we eat, increased serum cholesterol. In fact the opposite has been demonstrated several times. In 1937, 2 scientist proved just this and this study has never been refuted, nit even by Ansel Keys himself.

In 1955, president Eisenhower had a heart attack. He was 64 years old. 
His doctor, Dudley White put him on a special diet and joined Ansel Keys in his efforts to find the root cause for this epidemy.

Soon after, Keys came back with the infamous 7 countries study. This study aimed to show that saturated fats increased cholesterol and cholesterol caused heart disease.
You may ask yourself, why 7 countries. The real answer was because the other countries did not fit his theory.
Ansel started in Italy. He noticed that people there tend to be slim and their diet did not include much fat. The same for a few other countries, some of them he did not bother to visit. 
He failed to notice however, in addition to ignoring several other countries that refuted his theory, that these people were poor, living in a country still recovering from war. They simply did not have much food and led a very active lifestyle as a result of working in farms.
This study led to the cementation of the lipid hypothesis or diet heart hypothesis.
Back to president Eisenhower, the diet his doctor put him on was low in fat and high in carbs. His total cholesterol at the time was 165. By the time he left office his cholesterol was 259. And had a few more heart attacks after that.
He was also a 3 pack a day smoker. But at this time no one dared to speak up against the tobacco industry.

But, could the cholesterol be a factor?
One of the things worth remembering is that correlation is not causation. And just because cholesterol was present, it didn't mean it caused the heart attack.
It does, however, give scientist the right to look into it and ask the question.
Also, if correlation does not equal causation, one most also assume that non correlation must equal non causation. Meaning, if there's no correlation then we know for certain it didn't cause it.

One of the countries Ansel Keys included in his 7 countries study was Japan. Heart disease was almost non existent back then and they consumed little fat. But their fat consumption did increase since then, as noted by Dr. Malcolm Kendrick, and as a result heart disease fell by 60%. More interesting, stroke, actually fell by 700%.
Non Correlation equals non causation!
High cholesterol does not equals heart disease.

In fact high cholesterol has been linked with longevity and low cholesterol with an increase in total mortality. Which makes sense since cholesterol is required by every cell in the body.
Cholesterol we get from food, also, do not equal high serum cholesterol has demonstrated in 1937 study.
This has been again being demonstrated by Dave Feldman who, in an attempt to explain his high cholesterol results he showed, without any medical training, that an increase of dietary cholesterol will lead to the body producing less cholesterol.
The body works hard to maintain homeostasis.

 So what should we look at instead?

The particles are what matters. The number of LDLs, not so much.
A good thing to measure is your triglycerides against your HDL.
High triglycerides/HDL ratio can be caused by high consumption of carbohydrates, fructose especially.

Here's how it works.
LDL, low dense lipoproteins, travels from the liver to the cells. They are like big boats.
Inside, goes triglyceride,, cholesterol and vitamins that cannot go directly in the blood stream. 
Cholesterol will be called upon as and when needed. At the end of its journey they return to the liver, this time inside HDL to be recycled.
Triglycerides, 3 fatty acids combined by 1 glycerol, are energy and it is meant to be used as the LDL travels the body and eventually transferred to HDL, high dense lipoproteins. If not used, they will be stored with your fat reserves.
If your insulin is high, the cells will be ignoring the triglycerides, concentrating on glucose instead. 
If your triglycerides to HDL ratio is high, it means it wasn't used. And this means that you may be insulin resistant .

Insulin resistance is cause by having constant high blood sugars, high insulin present in the blood stream and fructose alone.
Insulin resistance has also been linked to inflammation, diabetes, cancer, alzheimer's and a myriad of modern diseases.

Conclusion: Insulin resistance kills people not cholesterol. And remember slim people can have high cholesterol as well as low cholesterol. The same goes for fat people. Cholesterol alone is not a good marker for disease.

What can we do if triglycerides are high?

Keto actually helps reducing triglycerides to HDL ratio by allowing the cells to access them as they travel in the body. The same goes for fasting. Basically anything that keeps insulin low will allow the use of triglycerides.
Keto will also improve your insulin resistance.

While on Keto, if your triglycerides over HDL are still high, then you may be consuming too much fat and all you need to do is eat less or exercise more so that the body uses that readily available energy.
If you are on a high carb diet, which means your insulin levels are too high and access to triglycerides will not be possible until insulin goes down, you may be still eating too much fat, or if you're on a low fat diet, you may be consuming too much fructose, which is turned into fat as it cannot be metabolised the same way as glucose. Exercising alone will not be enough, since you cannot out run a bad diet. You will need to drive insulin down but moving to a low carb diet or introducing periods of fasting.

I hope this helped a bit.
There's so many info out there. Just keep calm. And if you feel great, which tends to be the case when doing Keto, then do not worry about cholesterol.
That's my non-doctor opinion. You do what you need to do.