Why is it irregular? For now, let’s not consider differences in hormones or stress. That could be a factor too, but that is a harder thing to assess because there are so many reasons why hormones can fluctuate from day to day.
Think of your liver like a sailor on shore-leave. On some nights, it has just been paid and it goes out to the bars and spends it’s money buying drinks. It has a lot of money, so it buys a lot of drinks.
On some nights, it has no money. So the sailor sits quietly on the dock and carves his scrimshaw or plays his harmonica.
The more you eat, the more glucose (money) your liver (drunken sailor) will have available to spend.
On some days, if you have been eating full meals and have been less active, your liver is the drunken sailor spending money at the bar.
On other days, if your liver is not as fully replenished, it will be more stingy with it’s glucose and not give as much.
Everyone’s liver has about 100 grams of glucose it can store. And the amount is has at any given point is related to how much we eat and our activity levels and stress levels and all kinds of things that are happening with our body.
If your liver is at 80% it will share less than it will if it’s at 100%. If it is at 50%, it will share even less.
Your body has a built-in survival mechanism. It will never want to be fully depleted. The less it has, the more stingy it becomes.
We can see these things as diabetics. We can analyze our BG and know that our body is stocked up or depleted. We can look at our total daily dose and know how much we have been eating, if we are sick, tired, all kinds of things.
Others can never see these things.
It is hard to track stress or hormones. But it is easy to track food and activity and sleep.
Maybe a food/activity/sleep log can at least help you identify a pattern?