Insulin Resistance: The Root Cause Your Doctor Isn't Testing For
Look at the diagram above for a moment.
Type 2 diabetes. Heart disease. Stroke. High blood pressure. Fatty liver. PCOS. Dementia. Osteoarthritis. Obesity. Sarcopenia. The conditions we tend to think of as separate problems, each with its own specialist, its own medication, its own explanation.
Now notice what sits in the middle. One thing connecting all of them.
Researchers have increasingly linked insulin resistance to every condition on that diagram. Not as a coincidence. As a common thread running quietly underneath.
And here's what troubles me most, as a practitioner working with women in midlife: almost none of the women I meet have ever had it explained to them. They've been told they're getting older. They've been handed prescriptions.
But nobody has told them about what may be sitting at the root of it all.
What if one thing sat underneath so many of them?
We are taught to treat chronic conditions as separate conditions.
The cardiologist manages your heart. The endocrinologist manages your blood sugar. The rheumatologist manages your joints. Each one does excellent work within their specialty.
But what if some of these conditions share a common root? What if the reason so many symptoms seem to arrive together in midlife — the weight, the blood pressure, the aching joints, the fatigue, the brain fog — is that they are downstream of the same underlying process?
That process is insulin resistance. And once you understand it, a lot of what happens to women's bodies in midlife starts to make sense.
Insulin does far more than manage your blood sugar
Most of us were taught that insulin is the blood sugar hormone. You eat, your blood sugar rises, insulin brings it back down. True — but this is a fraction of the story.
Insulin is a master hormone.
It has receptors on almost every cell in your body. It influences how you store fat, how you build and keep muscle, how your blood vessels behave, how inflammation is regulated, even how your brain uses energy.
So, when insulin is chronically elevated — which is what insulin resistance is and creates — the effects ripple out far beyond your blood sugar.
This is why a single biochemical state can show up as so many seemingly unrelated conditions. Insulin is not just talking to your pancreas. It is talking to nearly every system in your body.
Why your glucose test isn't telling the whole story
Here's the gap that frustrates me most.
The current standard of care focuses on blood glucose. Your doctor tests your fasting glucose, perhaps your HbA1c, and watches those numbers. When they cross the threshold into prediabetes or diabetes, treatment begins.
But by the time your glucose rises, insulin resistance has often been developing for years — sometimes a decade or more.
Your body works hard to keep your blood sugar normal, and it does this by producing more and more insulin. So your glucose can look perfectly fine on paper while your insulin is quietly climbing in the background, driving effects throughout your body.
Insulin is not part of a routine blood panel. It is rarely tested. Which means the earliest, most manageable stage of this process — the years when lifestyle change makes the biggest difference — usually passes completely unnoticed.
This isn't a failure of individual doctors. It's a system built to catch disease once it has arrived, rather than the process that leads there. But for the woman living it, the result is the same: she isn't told until much later than she could have been.
Your body compensates — until it can't
Here's the piece that makes everything else make sense.
When your cells start resisting insulin, your body doesn't just let your blood sugar climb. It compensates.
The pancreas steps up and makes more insulin — enough to force glucose into cells that have stopped listening properly. And it works. Your blood sugar stays normal.
This is the clever part, and also the cruel part. Because it can go on for years. Sometimes a decade or more. Your pancreas quietly working harder and harder in the background, producing more and more insulin, holding your glucose in the normal range the whole time.
From the outside, everything looks fine. Your fasting glucose is fine. Your HbA1c — the three-month average most doctors rely on — is fine. Every standard screening test comes back reassuring.
But you don't feel fine. You're tired. The weight is creeping on despite your efforts. Your concentration isn't what it was. And when you raise it, you're told your bloods are normal, so it's probably stress, or age, or hormones.
The problem is that our entire testing system is built around the moment the compensation finally fails — the point where the pancreas can no longer keep up and glucose starts to rise. That's when you get a label: prediabetes, then diabetes. But the underlying process was there all along, developing quietly, for years before any routine test would catch it.
That gap — between when a woman starts to feel it and when the system finally names it — is where so much of midlife suffering lives.
The problem is chronically raised insulin
Let me explain about what insulin resistance actually is (without turning this into a lecture).
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It is a state in which your cells stop responding well to insulin. To compensate, your body produces more of it. The result is chronically elevated insulin — and it's that chronic elevation, sustained over years, that appears to drive so much downstream harm.
Two things raise insulin.
The first is what and when we eat — particularly refined carbohydrates and frequent eating that never gives insulin a chance to fall.
The second is our own body fat: once we cross a certain personal fat threshold, our stored fat itself contributes to raising insulin, which makes it harder to lose the fat, which raises insulin further.
It's a genuinely complex situation, driven by many factors — genetics, hormones, sleep, stress, movement, and yes, the natural loss of insulin sensitivity that comes with age.
But here is the part that matters most: it is remarkably responsive to dietary and lifestyle intervention.
This is not just a diabetes conversation
If you take one thing from this post, let it be this: insulin resistance is not only about diabetes.
Diabetes is simply the diagnosis we've built a testing system around. But researchers have increasingly linked insulin resistance to a much wider range of conditions — the ones on that diagram, and the everyday midlife symptoms that rarely earn a diagnosis at all.
Think about what so many women describe from their mid-forties onward. The stubborn weight around the middle. The afternoon energy crash. The brain fog that rolls in for no clear reason. These are usually attributed to declining estrogen — and estrogen does play a genuine role, including in how the body handles insulin. But insulin resistance is rarely considered as part of the same picture, and almost never tested for.
The brain, it turns out, has its own insulin signaling system, and researchers have linked impaired brain insulin signaling to the cognitive changes many women notice in midlife.
That afternoon fog may not be a character flaw or simply 'getting older'. It may be biochemistry — and biochemistry can be worked with.
None of this means insulin resistance is the sole cause of every condition it's linked to. These are complex conditions with many contributors. But when one factor keeps appearing underneath so many different problems, it deserves our attention — especially when it's a factor we can actually do something about.
Why a plaster over the symptom is not the answer
There is a place for medication. There is a place for supplements. I'm a natural medicine practitioner and I use them thoughtfully every day. This is not an anti-medicine message.
But treating each downstream symptom in isolation — a tablet for the blood pressure, a tablet for the cholesterol, a tablet for the blood sugar — without ever addressing what might be sitting underneath is, in many cases, like sticking a plaster over the problem.
It covers the symptom. It doesn't touch the root.
When something can be addressed at the root — through the food you eat, the way you move, the way you live — that is worth understanding. Not instead of good medical care, but alongside it.
The good news — insulin resistance responds to how you live
This is the part I most want women to hear.
Insulin resistance is one of the most modifiable states in all of chronic health. It responds to what you eat. It responds to how you move. It responds to sleep, to stress, to muscle.
This is lifestyle medicine in its truest sense — not a vague wellness slogan, but a measurable biochemical state that shifts when you change what you're doing.
That is an extraordinarily hopeful message.
It means that a great deal of what feels inevitable about ageing may not be inevitable at all. It means there is often something you can do — not a magic fix, not a quick one, but a real and lasting one.
And it means you don't have to wait until a number crosses a threshold to begin.
Frequently Asked Questions
What is insulin resistance?
Insulin resistance is a state in which the body's cells become less responsive to insulin, so the body produces more of it to compensate. This leads to chronically elevated insulin levels. Because insulin affects nearly every cell in the body, this state has effects that extend well beyond blood sugar regulation.
Is insulin resistance the same as diabetes?
No. Type 2 diabetes is one possible outcome of long-term insulin resistance, but insulin resistance can be present for many years before blood glucose rises enough to meet the threshold for diabetes. It is a much broader biochemical state that has been linked to a wide range of chronic conditions.
Why isn't insulin resistance routinely tested?
Standard blood panels typically measure blood glucose rather than insulin. Because the body works to keep glucose in a normal range by producing more insulin, glucose can appear normal while insulin is elevated. Insulin testing is available but is not part of routine screening, which means early insulin resistance often goes undetected.
What causes chronically raised insulin?
The main drivers are dietary — particularly refined carbohydrates and frequent eating patterns — and body fat levels beyond an individual's personal threshold. Other contributing factors include genetics, hormonal changes, sleep, stress, physical activity, and the natural decline in insulin sensitivity that occurs with age.
Can insulin resistance be improved through diet and lifestyle?
Insulin resistance is considered one of the most modifiable states in chronic health. It responds to changes in nutrition, physical activity, sleep and stress management. This is why lifestyle-based approaches are central to managing it, and why understanding your own metabolic health is so valuable.
Why does insulin resistance matter more for women in midlife?
Insulin sensitivity naturally declines with age, and hormonal changes during perimenopause and menopause can affect how the body handles insulin. This is part of why many women notice changes in weight, energy and body composition in midlife that they hadn't experienced before.
Want to understand your own metabolic health?
If this post has you looking at your own health differently — the weight that won't shift, the energy that isn't what it was, the sense that something underneath needs attention — then let's talk.
My Discovery Call is free, twenty minutes, and completely no-pressure. It's a chance to talk about where you are and whether understanding your insulin health could be the missing piece for you.
Curious how I came to this work myself?
Cherice Baker is a Registered Natural Medicine Practitioner (NHPNZ) and certified InsulinIQ Coach with over 25 years of clinical experience in nutritional medicine, herbal prescribing and functional health. She specialises in metabolic health for women in perimenopause, menopause and midlife, and consults with clients across New Zealand online.
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