I was having a discussion about epilepsy. That led to high ketones which led to how you get high ketones and when.
This led me to the paper below.
Oxaloacetate Deficiency in Mct-Induced Ketogenesis
This is a study on why MCT causes increased ketones but it tells us so much more. Let’s start with how ketones are made:
Ketones are made when insulin is very low and all stored glucose in the liver has been depleted. That is the basic part of it. Lets get a little deeper. First we have to look at the Krebs cycle or also known as the citric acid cycle. The Krebs cycle is the first major step in ATP creation.
It all starts with AcetylCoA at the top but the other major player we are going to talk about today is just to the left, Oxaloacetate. When insulin is very low there will be lots of fat being released from adipose tissue. When glucose is broken down for use in the krebs cycle it only results in one AcetylCoA but when fat is used it breaks down to two. When you have lots of AcetylCoA like when insulin is low then you end up having a limiter in the amount of cycles the krebs cycle can turn due to the limit of Oxaloacetate. Oxaloacetate is also needed to run another process we know about, gluconeogenesis or GNG for short. Since GNG is critical to the maintenance of blood sugar level it gets priority over the amount of oxaloacetate that is supplied to the Krebs cycle so there is a limit to the amount of AcetylCoA that can be turned to ATP. When you have lots of fat converted to twice as much AcetylCoA and the krebs cycle is limited in how fast it can process it, you get a build up of AcetylCoA waiting at the krebs cycle door. This results in ketogenesis.
So now we understand that when we have ketones we already have more AcetylCoA than the krebs cycle can use to create energy so it gets diverted to ketones. Now lets look at MCT oil and what it does.
MCT oil cannot be stored as fat. It must be oxidized in the liver to AcetylCoA. When we have ketones in the blood this means we already have too much AcetylCoA so adding MCT oil at this time is not going to do anything other than make more ketones. It can’t go through the Krebs cycle any more than any of the other fats at this point. All it is doing is keeping the AcetylCoA pool full and generating ketones. We only need so many ketones. More ketones does not equal more energy. ketones are not energy. They are potential energy. Just like glucose and just like fats. They are just a potential energy source. They still have to be metabolized like any other fuel and having more of it does not mean we are going to use it. Ketones will really only be used in certain tissues like brain and red blood cells and they can only use so much. Having super high levels is not a benefit. Especially when it is MCT oil supplied. You are better off to leave it out.
Now why won’t it help you lose weight and might actually keep you from losing weight.
Because it goes right to the liver while other fats go to adipose first before they get into circulation, MCT oil is going to take precedence over other fats in the AcetylCoA pool. It has to be utilized first because it cannot be sent back to storage and it can’t circulate in the blood. It must be used first. If it is taking precedence then it will leave fat that has come from adipose tissue, like your own bodyfat, in circulation where it could eventually make it back into storage if and when insulin levels rise.
Writing this article led me to discover an answer to why people tend to make less ketones the longer they are on keto but that will be an article for another day. 🙂