Insulin Resistance and Weight Loss: Why Your Body Is Working Against You

Sharon Carius

Clinical Nutritionist, Metabolic Balance® Practitioner

3 September, 2026

You have cut back on food. You are moving more than you have in years. You have done the thing everyone told you to do, and done it properly, for months.

And the scale has not moved. Or it has moved in the wrong direction.

If that is where you are, I want to say something clearly before we go any further: this is not a discipline problem. There is a specific, measurable, well-documented biological process that makes weight loss significantly harder for some women than others, and it is almost certainly not being tested for in your standard blood work.

It is called insulin resistance. And once you understand how it works, a great deal of what has been happening to your body starts to make sense.

What insulin resistance actually is

Insulin is a hormone your pancreas releases whenever your blood glucose rises — which is to say, after most meals. Its job is to move glucose out of your bloodstream and into your cells, where it can be used for energy.

Think of insulin as a key, and your cells as doors. Insulin arrives, unlocks the door, glucose goes in. That is the system working properly.

With insulin resistance, the locks stop responding well to the key. Glucose stays in the bloodstream longer than it should. Your pancreas notices this and does the sensible thing: it makes more insulin. More keys, to force more doors.

For a while, this compensation works. Your blood glucose looks normal. You feel mostly fine. Nothing shows up on a standard test.

But you are now walking around with chronically elevated insulin — and this is where weight comes into it.

Insulin is a storage hormone. When insulin is high, your body is receiving a clear instruction: store energy, do not release it. Fat cells take up glucose and hold onto what they have. The metabolic pathway that releases stored fat is effectively switched off while insulin remains elevated.

So you can be in a calorie deficit and still find fat loss extraordinarily slow, because the hormonal signal telling your body to hold on is louder than the deficit telling it to let go.

This is the part almost nobody explains. It is not that calories do not matter. It is that the hormonal environment determines what your body does with them.

Why the standard advice can make it worse

Here is the uncomfortable part.

The conventional response to stalled weight loss is to eat less and exercise harder. For someone with meaningful insulin resistance, that approach frequently backfires — and there is a mechanism behind why.

Aggressive restriction is a physiological stressor. So is excessive exercise without adequate recovery. Both raise cortisol, your primary stress hormone. And cortisol has a direct effect on glucose metabolism: it prompts the liver to release stored glucose into the bloodstream, which in turn prompts more insulin.

You are, in effect, trying to solve a high-insulin problem with a strategy that raises insulin.

This is why so many women describe the same pattern — that the harder they try, the more stuck they become, and the worse they feel while doing it. That experience is not a failure of effort. It is a predictable outcome of applying the wrong intervention to the actual problem.

Restriction also tends to produce the exact eating pattern that worsens insulin resistance: long gaps, low protein, then a large or carbohydrate-heavy meal when hunger finally wins. Each of those swings is another insulin spike.

Signs that this might be part of your picture

None of the following confirms insulin resistance on its own. Taken together, they are a reasonable prompt to look further.

• Weight that accumulates around the middle rather than distributed elsewhere
• A distinct energy crash an hour or two after eating, particularly after carbohydrate-heavy meals
• Cravings for sugar or starch that feel physical rather than psychological
• Waking around 3am, or difficulty getting back to sleep
• Feeling hungry again shortly after a substantial meal
• Skin tags, or darkened patches of skin around the neck, armpits or groin
• A family history of type 2 diabetes
• Weight that will not shift despite genuinely consistent effort

The last one is what usually brings women into my clinic. They have done everything correctly and the results do not match the input.

Why standard blood tests often miss it

This is the piece I most want women to understand, because it explains years of being told everything is fine while feeling anything but.

The test most commonly ordered is fasting glucose. It measures how much sugar is in your blood after not eating overnight.

The problem is that fasting glucose is the last thing to change.

Remember the compensation described earlier — your pancreas producing extra insulin to force glucose into resistant cells. That compensation works. Your blood glucose stays within the normal range, sometimes for a decade or more, precisely because your body is working extremely hard behind the scenes to keep it there.

Fasting glucose only becomes abnormal once that compensation starts to fail. By then the underlying process has been developing for years.

Fasting insulin — which measures how much insulin your body needs to maintain that normal glucose — is far more informative at this stage. It is not routinely ordered in standard screening, because standard screening is designed to detect disease, not to identify metabolic dysfunction well before disease appears.

This is a genuinely important distinction. "Your bloods are normal" often means "you do not yet have a diagnosable condition." Those are not the same statement, and the gap between them is where most of my clients have been living, frequently for years.

Understanding what your blood chemistry is actually showing — across a wider range of markers than a standard panel covers — is where meaningful change usually starts. That is the basis of the Blood Chemistry Analysis I use with clients.

What genuinely improves insulin sensitivity

The encouraging news is that insulin sensitivity is highly responsive to the right changes. This is not a permanent state. It is a pattern that can shift, and often faster than people expect.

Meal composition matters more than meal size. Protein, fat and fibre alongside carbohydrate slows glucose absorption and blunts the insulin response. The same food eaten in a different order or combination produces a measurably different curve.

Spacing between meals allows insulin to fall. Continuous grazing keeps insulin persistently elevated, which keeps the storage signal on. Adequate gaps between structured meals let it drop, which is when fat release becomes possible.

Protein at breakfast changes the whole day. A carbohydrate-dominant breakfast sets up the glucose-and-crash cycle that drives cravings from mid-morning onward. Starting with adequate protein interrupts it.

Resistance training improves glucose uptake independently of insulin. Muscle is metabolically active tissue. Working it creates a pathway for glucose that does not require insulin at all — one of the reasons strength work outperforms cardio for this specific problem.

Sleep is not optional here. Even short-term sleep restriction measurably reduces insulin sensitivity in healthy people. If you are averaging five or six hours, that alone may be holding the pattern in place.

Stress load has to be part of the conversation. Cortisol and insulin are linked. Addressing food while ignoring chronic stress usually produces partial results at best.

Chronic stress is one of the more common contributors to this pattern — I've covered how cortisol drives abdominal weight gain separately.

What matters most is that these interventions are matched to your biochemistry rather than applied generically. The right protein amount, the right carbohydrate tolerance, the right meal timing — these vary considerably between individuals, and that variation is exactly what blood chemistry reveals.

Not sure whether this describes you?

If you are still working out whether insulin resistance is part of your picture, I have written a more detailed guide to recognising the signs over at Metabolic Health for Women, which covers what to look for and when it is worth investigating further.

Where to go from here

Insulin resistance is common, frequently missed, and highly responsive to the right approach. What it does not respond to is more restriction and more willpower applied to a problem that was never about either.

Here is what I would suggest, depending on where you are starting.

Option 1: Start with the 14-Day Metabolic Kickstart

If you want to begin making changes without committing to a full programme, this builds the foundations — stabilising blood sugar, reducing cravings, structuring meals in a way that lets insulin fall between them.

It is the same groundwork many of my Metabolic Balance® clients build before their personalised plan begins.

Start the 14-Day Metabolic Kickstart

Option 2: Book a Health Strategy Session

If you would rather understand what is actually driving your situation before deciding anything, this is a focused 40-minute consultation. We look at your history, what you have already tried, and whether a blood-chemistry-based approach makes sense for you.

The session is $150, with $100 credited toward any programme you go on to start.

Book a Health Strategy Session

Option 3: A plan built from your own blood chemistry

Metabolic Balance® builds your nutrition plan from analysis of more than 30 of your own blood markers, alongside your health history and food preferences. For insulin resistance specifically, this matters — the right carbohydrate tolerance, protein requirement and meal structure are individual, and a plan built from your actual biochemistry is a different proposition to a plan built from general principles.

Explore Metabolic Balance®

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