I know there are all kinds of exceptions. However, if we start looking at all the different possibilities and say “but, but, but”, we can end up swimming in circles. So I just want to give a very general rule for this this sort of stuff works. And not get too caught up in all the millions of scenarios and different things happening.
Just very basic…
As discussed previously, the body uses liver glycogen for fuel when you are not eating. It doesn’t need it when you have food in your stomach and then glucose in your blood right after a meal. But when you do not have a meal, your body needs fuel which it gets from the liver.
In the normal non-diabetic body, when you eat, your body releases insulin. And your liver reads that increase in insulin as a signal. It says, “Hey there is more insulin here than usual, so that means Allison is eating. Since she is eating now, I don’t need to release glucose. Now would be a good time to bank some of this food for later use!”
Your body is so smart. The body wants to preserve itself, so at times of being fed, it takes some of that food and stores it for later.
Another way of viewing this is simply that higher amounts of insulin (when in a fed state) equates to higher amounts of carb storage.
When your body has less insulin, it will not store as much. Your smart liver says, “There is not much insulin here. That means Allison has not eaten much recently! Now is not a good time to store food.”
So while this is a very simplistic explanation, it is however clearly demonstrated by microbiology.
When insulin is absent from cells, Glycogen Synthase Kinase 3 (GSK3) phosphorylates Glycogen Synthase. This phosphorylation inactivates Glycogen Synthase. Glycogen synthase is a key enzyme used in glycogenesis (the conversion of glucose into stored glycogen). And when Glycogen Synthase is inactivated, glycogenesis is not possible.
So if my simplistic explanation does not seem like it is correct, simply look at the more scientific explanation in the few sentences directly above, and see that it really does work that way.
When fed, your body stores more. When unfed, it stores less and releases instead.