I was going to call this article glycogenolysis versus gluconeogenesis, but I realized that that might be too technical of a title for a post and might scare some people away, but that's our topic here. So what I'm talking about here might seem to be pretty technical and esoteric, but what this all boils down to is looking at the role what we eat has to do with how much liver dumping we have, so diet and liver dumping seemed like a more catchy title.
When we consume glucose, some of that glucose gets stored as glycogen, in the liver and the muscles, although glycogen stored in the muscles is there to be used locally, as opposed to entering the general circulation, and since we're talking blood sugar levels here we're speaking of glucose in circulation, so in our case this will mean a certain amount of glucose being stored in the liver as glycogen.
We can store a fair bit of glycogen in fact, and this is glucose that is readily available to us to be used when needed, to provide us with a ready reserve of glucose. In healthy individuals, we will use this store to provide us with energy when we're not eating food, as required.
So some people have thought, well if we look to keep glycogen reserves low, by restricting glucose in our diet, then we can limit the amount of excess hepatic glucose secretion, what we commonly call liver dumping. People indeed can achieve lower blood sugar by restricting glucose intake, and given that liver dumping contributes to excess blood sugar, therefore restricting glucose results in less excessive liver dumping.
The logic of this is completely faulty though. We're really speaking of two different mechanisms of blood sugar regulation, ingested glucose and what we can call internal glucose, some call the glucose we eat as exogenous glucose and the glucose from the liver as endogenous glucose.
So how does exogenous glucose influence endogenous glucose? Well they are regulated differently, the glucose that comes from our digestive system, which is the exogenous stuff, is regulated by what we eat and our digestion of it. So some of this gets stored as glycogen in the liver.
Does the amount of glucose secreted by the liver from glycogen depend on the amount of glycogen in the liver? Well no, and this is the mistake that people tend to make. Now there are cases where glycogen reserves can be kept low, in nutritional ketosis, and then people think, well it's because I'm eating a ketogenic diet that is very low in glucose that is why glycogen is low, and the low glycogen is the reason why my blood sugar may be lower, but that's not really the case.
Rather, it is because when one is in nutritional ketosis, one gets most of their energy requirements from fat, not glucose, and therefore the body relies on glycogen a lot less, and it is therefore released less. This has a lot more to do with downregulating insulin secretion than anything else, provided one is able to do that, and this is likely what separates people who do better on these diets and actually achieve nutritional ketosis, versus those in which dietary restriction is insufficient to downregulate insulin secretion enough and therefore can't really achieve it properly.
If your insulin secretion is low, and the need for it is also low, then less glycogen will be stored, and lower blood sugar can be achieved, but this doesn't mean that the lower glycogen itself is the reason behind it and we can do this with just restricting dietary glucose and it will always work.
So what we've done here is change the way we regulate this, changing the need for the liver to secrete glucose, and this is not a matter of not having any available, having the tank run dry, the tank is less full but that has nothing to do with the regulation.
A good way to think of this is to see glycogen storage as a gas tank, with glycogen being the gas, and internal glucose regulation being the engine, and it's what's going on with the engine that is going to determine things here.
There's another gas tank that we need to talk about though, and this is called gluconeogenesis, where the liver creates glucose not from glycogen but from non glucose sources, things like pyruvate and lactate, byproducts of cellular metabolism, and from certain amino acids.
So glucose from glycogen isn't really regulated by diet except in the case of ketosis, but gluoneogenesis is different, as while glycogen does depend on the diet for its source, and you can actually deplete it, empty the tank in other words, if you wish, you can't empty the gluconeogenesis tank, as it is not dependent on diet at all.
So for us to get glucose from glycogen there must be glycogen present, and without eating for an extended period we will run out and die, and gluconeogenesis is what saves us when this happens.
Some wonder why keto diets work so well with some diabetics and not so well with others, and the reason is that if you have too much gluconeogenesis going on, this will keep blood sugar elevated completely independent of diet, and to be in nutritional ketosis, to get the majority of your energy from fat, you can't do this with a lot of gluconeogenesis going on because this will provide in itself more glucose than the body can handle, and the body will always prefer glucose over fat for energy, and fat for energy is just a back up process really, in spite of what some keto people may think.
So glucose restriction can be helpful but it is often not sufficient to normalize blood sugar, and excess gluconeogenesis is a big reason why. How much of liver dumping is due to gluconeogenesis and how much is due to glycogenolysis, the conversion of glycogen to glucose? Well a lot of people think it's mostly from glycogen, and in normal people it is, but not in diabetics generally.
We've studied this in diabetics, on average, 89% of hepatic glucose with us has been found to come from gluconeogenesis actually, with only about 11% from glycogen conversion. This might not seem to be that meaningful at first glance, but given that we know that all excess blood sugar comes from liver dumping, if you take away the liver dumping in other words you don't have high blood sugar regardless of your diet, this means that 90% of the extra glucose in our blood does not come from our diet at all, although this number does differ a fair bit between diabetics, depending on the degree of excess liver dumping you have.
Of course this doesn't mean that one's glucose intake isn't significant, it surely is, as glucose is glucose, and diet does contribute a significant amount of PP or after meal glucose load, although a good part of the excursions we see after meals is due to liver dumping as well, which we've shown clearly to be the case.
So the practical implications of all of this is that looking to reduce excess gluconeogenesis needs to be a primary target in managing diabetes, this is what medications like Metformin, berberine, and gynostemma do, with Metformin being the prescription medication and the other two being non prescription herbal preparations, and Metformin is actually a synthetic analogue of a herb actually.
This stuff in themselves only help somewhat, and we need to work harder on managing liver dumping more effectively if we want to manage diabetes itself more effectively, and while there are lots of other considerations, it is clearly not so simple as thinking you can just limit your glucose intake and limit glycogen reserves and lick this thing every time, as some people think.