So once upon a time, it was thought that elevated insulin was caused solely by elevated blood glucose.
It turns out there are several pathways to elevating insulin. (And this explains why merely low-carb is sometimes not enough to deal with it.)
And while elevating glucose seems (so far) to be the main one, more recent research suggests that the insulin may be elevated, returning the glucose to normal levels promptly, which is perceived in blood tests as ‘normal / non-diabetic’, for years, even decades for all we know, before the situation with hyperinsulinemia gets bad enough long enough that finally the muscle cells and even adipose cells start resisting the onslaught – and THEN it shows up as blood glucose problems.
So it is the case that people may spend a good chunk of their life hyperinsulinemic but since doctors don’t test insulin, only glucose (and even that only sometimes), it gets completely missed.
Theories on why this is the norm have two sides:
On one hand, the pharma mfrs would love to make the $ from a gazillion new instant customers who suddenly realize they are on the path to diabetes.
On the other hand, the absolutely staggering percentage of the population who would promptly be diagnosed, would make it far too obvious that our primary USDA food push (grains and produce) is dosage-poisoning the entire population, and many powerful sources have gone to great lengths to make sure that is not apparent… and we simply blame individuals for moral failing (all of them), rather than looking seriously at what government and corps have done to the nation and gradually much of planet earth.
(There is an old Star Trek: The Next Generation episode (season 1: episode 21 free if you have amazon prime) where residents of one planet have basically enslaved the residents of another planet with a drug which is insanely expensive. The one planet works all the time, in near poverty, to afford this drug which must be taken regularly to save them from this incurable disease (which turns out to be detox from the addictive drug. Which originally was, truly, for that illness, but the illness vanished eons prior). The other planet of people live in luxury off the money people from the other planet spend on the drug. It’s incredibly insightful as a parallel to the situation with “ingestible entertainment” – which our culture does not seem to realize is intentionally designed addiction. Sorry I’ve just exposed myself as a Trek nut. )
Back to the point: so it is not like insulin resistance fell on you outta the sky based on the position of the stars or something. It’s simply that for some people the situation is under the radar – simply because our medicine doesn’t measure in a way to find it.