Insulin Resistance: What is it? Do I have it?
- 20 hours ago
- 5 min read
And how can I prevent or reverse it?
What is Insulin Resistance?
Insulin resistance is bad news. And if you suspect you might have it, there’s a reasonable chance that you do. In fact, experts estimate that more than 50% of New Zealanders are living with some degree of insulin resistance.
Insulin resistance is the root driver of modern chronic illness. When your blood is constantly flooded with insulin, it creates a domino effect that – in time – leads to Type 2 Diabetes. In the meantime, it significantly spikes your risk for the “Big Four”: heart disease, cancer, dementia, and kidney disease, as well as conditions like PCOS.
So, what is insulin and insulin resistance?
Insulin is a hormone that regulates blood sugar. Think of insulin as a key: it unlocks your cells so that glucose from the food you eat can move out of the bloodstream and into your cells, where it’s used for energy or stored for later use.
The trouble starts when that lock gets “jammed”. When you become insulin resistant, the key is not working as well and your body needs more and more insulin to achieve the same effect.
What causes insulin resistance? Why does the lock get jammed?
There is rarely just one cause. Genetics play a role, and factors such as chronic stress, poor sleep, and hormonal changes – including menopause – can all contribute. The list of possible causes is quite long. However, for many people, one of the biggest drivers is what we eat and how often we eat.
When we regularly consume foods that rapidly raise blood glucose – such as sugar and refined grains – and we eat from early morning until late at night, insulin levels never get a chance to drop.
Over time, your body adapts and becomes less responsive. In a way, your body is trying to protect itself and keep things in balance. Unfortunately, the persistently high insulin levels will set you up for a wide range of health problems.
One particularly frustrating consequence is weight gain – or the inability to lose weight. When insulin is high, your ability to burn fat is effectively switched off. Think of insulin as a toggle switch. When it is high, you are in storage mode. When it is low, you are in burn mode.
The good news is that this switch can be flipped. By changing what you eat and how often you eat, you can bring insulin levels down. When insulin stays down for longer periods, the body begins to heal, the weight begins to move, and the insulin resistance is starting to reverse.
But first, let’s explore how to tell whether you might have insulin resistance.
Do I have it?
As mentioned earlier, it is estimated that more than half of all adults in New Zealand are insulin resistant to some degree. Broadly speaking, this breaks down into three groups:
Insulin resistant but still keeping blood glucose in check: approximately 30–40% (an educated guess)
Prediabetes – insulin can no longer keep blood glucose within a healthy range: approximately 20–26%
Type 2 Diabetes – insulin production is impaired and blood glucose is persistently elevated: approximately 5–6.4%
Stage 1: Insulin Resistant (Elevated insulin but blood glucose remains stable)
At this stage, insulin resistance often develops gradually and quietly. If no diet or lifestyle changes are made, the body typically compensates by producing higher and higher levels of insulin to keep blood glucose under control. This stage often goes undetected on standard blood tests, but there are some important clues to watch for:
An expanding waistline: Waist circumference is a better predictor of insulin resistance than BMI. You can be insulin resistant even at a normal body weight if visceral fat, the fat stored around your organs, is elevated.
Post-meal symptoms: These may include fatigue or sleepiness after eating, brain fog, strong cravings for carbohydrates, or feeling hungry again soon after meals.
Subtle changes in blood lipids: Common patterns include rising triglycerides, falling HDL (good) cholesterol, A rough guide for the triglyceride-to-HDL ratio is:
under 1.5: insulin sensitive
approximately 2: insulin resistant
3 or higher: strongly insulin resistant
These changes reflect insulin’s effect on how the liver handles fat.
Fasting insulin levels: A fasting insulin test can be one of the most informative markers of insulin resistance, yet it is rarely ordered in New Zealand. It may be worth asking your GP whether this test would be appropriate for you.
Stage 2: Prediabetes
Most people will have spent 10 to 20 years in the initial insulin resistant stage before progressing to prediabetes. Eventually, the body can no longer compensate and blood glucose levels begin to rise. Prediabetes is typically indicated by one or more of the following markers:
HbA1c: 41–49 mmol/mol
Fasting glucose: 6.1–6.9 mmol/L
2-hour glucose on an Oral Glucose Tolerance Test (OGTT): 7.8–11.0 mmol/L
Identifying this stage matters because you can still intervene and prevent progression to Type 2 Diabetes.
Stage 3: Type 2 Diabetes
At this stage, the cells in the pancreas can no longer sustain the high levels of insulin required. As insulin production begins to fall, persistently elevated blood glucose (hyperglycaemia) develops. Common warning signs include the “4 Ts”:
Toilet: Needing to urinate frequently, especially at night
Thirst: Feeling excessively thirsty and unable to quench it
Tired: Feeling extreme fatigue or a persistent lack of energy
Thinner: Unexplained weight loss
If you suspect you have Type 2 Diabetes, see your GP at the earliest opportunity.
What can I do about it?
While some causes like genetics and ageing are out of our control, there are multiple proven ways for reversing insulin resistance:
Adopt a low-carbohydrate, healthy-fat diet. This keeps insulin levels low. It can be further supported by time-restricted eating.
Move your body and exercise regularly. Physical activity allows muscles to take up glucose without requiring as much insulin.
Reduce stress and prioritise sleep. Chronic stress raises cortisol, which increase insulin resistance. Furthermore, even one week of poor sleep can make your body significantly more insulin resistant.
Consider hormone replacement therapy (HRT). For those entering menopause, the decline in estrogen directly reduces insulin sensitivity. Taking HRT is a personal choice that should be discussed with a professional.
Minimise exposure to things that make insulin resistance worse. These include cigarette smoke, nicotine (including nicotine gum and e-cigarettes), certain pesticides, MSG, BPA, sugar, and most artificial sweeteners.
How I can help
As a Nutritionist and Health Coach, I help clients create personalised nutrition and lifestyle plans that reduce and reverse insulin resistance. These plans are tailored to your health history, your dietary preferences (not everyone likes broccoli!), and your personal circumstances.
If this article has motivated you to make some positive changes, you are welcome to check out my programmes or book a free consultation session. This session is a relaxed, no-obligation chat where we explore your goals, your challenges, and whether my programmes might be the right fit for you.
For more information, check out: “Why we get sick. The hidden epidemic at the root of most chronic disease – and how to fight it” by Benjamin Bikman (2020)
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