If you’re on a Low Carb High Fat diet (LCHF), there are a few things you should know about cholesterol and how it is related to this lifestyle. In this guide I plan to cover the topic in very simple terms. It is by no means complete and is intentionally simplified to make it easier to read and understand for the layperson.
Our Energy on a High Fat Diet
Before talking about cholesterol, we have to talk about the energy you get from fat when on LCHF. Of course the main reason for food is to supply your body with energy. But how does that energy get to everywhere it needs to go in your body?
Like every other living thing, your body is made up of cells. Your heart is made of cells. Your brain is made of cells. So are your fingers, knees and toes. Almost all these cells need energy. And the vast majority of these cells ultimately get their energy from the blood circulating around your body.
The most commonly talked about source of energy is carbohydrates (carbs). Your body turns carbs into glucose to put in the bloodstream. From there the glucose can circulate throughout the body, allowing hungry cells to grab some for themselves, and this is done with the help of insulin.
The other major energy source for your cells is fat, and by that I mean fatty acids. And like glucose, your cells also get their fatty acids from the bloodstream. Only there’s an important catch: glucose can swim in the bloodstream easily, but fatty acids cannot.
Fatty acids and the bloodstream are like oil and water, they don’t mix well. To fix this, your body cleverly does two things:
- It packages three fatty acids into a combo pack molecule called a “triglyceride”.
- And it makes a kind of boat for these triglycerides to travel in called a “lipoprotein”.
In fact, the kind of lipoprotein that delivers all these fatty acids is known as a low density lipoprotein — but you probably know it already by it’s abbreviation, LDL.
Common Confusion with LDL
Odds are you have most likely heard of LDL being used to describe cholesterol on a blood test. “Your LDL is high…” for example. So what gives?
Here’s the thing about cholesterol, like its triglyceride cousin, it also doesn’t swim well in the bloodstream. In the medical world, these molecules are commonly referred to as lipids. And lipids are actually repelled by water, so they are commonly called hydrophobic (hydro = water, phobic = repel). So when someone tells you they love to go to the beach but hate the water, mention they must be hydrophobic like cholesterol!
Yet what if the body has reason to have cholesterol available in the bloodstream as well? (We’ll get into that more in Part II) And while we’re on the subject, there are a few other things the body wants available to cells that are also hydrophobic, such as fat soluble vitamins (like Vitamin E).
So should it make a separate lipoprotein container for each of these molecules? No! It effectively packages all of them into the same boat: the low density lipoprotein.
That’s the genius of the human body. It has a kind of FedEx for all the hydrophobic elements needed by the cells. And most of whatever isn’t used gets recycled by the liver for many other possibilities, such as hormone or bile salt production.
Common Confusion with Triglycerides
The odds are likewise that you’ve heard “triglycerides go down on a low carb diet”. Indeed, blood tests for those going LCHF are almost universally lower in triglycerides. But a measurement of anything in the bloodstream is counting what is traveling around in that moment and not yet in use.
For example, Type 2 Diabetes has a common symptom of having very high glucose in the blood. This is because these diabetics are insulin resistant and have trouble getting the glucose out of the blood and into their cells. They may eat the same quantity of food as someone who isn’t diabetic, but glucose in the blood will spike higher and last longer by comparison.
If you have reduced your carbs and now get your energy mainly from fat, without question your cells are absorbing more of it from the bloodstream now. So even if you’ve increased the total amount of triglycerides going into the blood due to the diet, it is still brought down by the amount getting taken back out and used by the cells.
Common Confusion With Ketones
Another common assumption with LCHF is that you “get the majority of your energy from ketones” since you are in a state of ketosis. It’s certainly true your body makes many more ketone bodies from breaking down fatty acids, which will likewise feed your cells. This is especially important for proper brain function as ketones have special access that lipoproteins do not.
Yet while ketones are both produced and used much more on LCHF, they are still a secondary source of energy. The primary source of energy is still fatty acids brought to cells in LDL particles.
More Cholesterol is Trafficked on a Low Carb High Fat Diet
Now that you understand your body has need to move around more triglycerides to fuel your cells while getting the majority of your energy from fat, you may have already connected the dots.
- Your cells need energy
- On a high fat diet, their primary source of energy is triglycerides
- To get the triglycerides to your cells, your body sends them in low density lipoproteins
- All low density lipoproteins are made containing both triglycerides and cholesterol (but mostly triglycerides)
What are the Risks?
If you read the above and are struck with fear, I don’t blame you. It has been well drilled into our heads that more cholesterol in the blood = higher risk of cardiovascular disease and stroke.
But if you’re early in your research on this topic, let me help you skip ahead with one very crucial point (which I alluded to above). Making something available is not the same as using it.
Here’s a simple analogy – life rafts in the water and being used are typically a sign of trouble. Yet all ships sail with them on board. This is a good idea in case of an emergency, of course. But if you were only counting life rafts whether in use or not, then you’d assume a lot of ships entering view was by itself a sign of trouble.
Cholesterol is like the life rafts on the LDL ships. Even if it travels with your triglycerides, it is a much smaller passenger (in quantity) and mostly recycled back at the liver. You don’t actually care how much cholesterol is in your blood — you care how much cholesterol leaves the bloodstream and causes a build up of plaque in your arteries (atherosclerosis). And this is at the core of the inflammation debate with cholesterol. Is it a life raft for damage to the blood vessels? Or is the sheer presence of it risk alone? (You can probably guess where I fall on this one.)
In Part II we cover part of the journey of cholesterol in more detail through a very visual comic form. (Part III is coming soon…)
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