Introduction
You eat right, you workout, and yet the weight won’t budge at all. Your energy crashes after each meal. Yet your doctor mentions “borderline sugar levels”. Sounds familiar right?
Millions of people are now living with a hidden metabolic condition, the one that silently drives fatigue, weight gain, and a chronic disease without you barely knowing about it. This is called insulin resistance, and it is certainly affecting you too.
Since the discovery of insulin in 1921, research has exploded and today, scientists are also agreeing that insulin resistance is one of the most significant metabolic drivers behind the biggest diseases of our time. But do you know what is actually causing it?
This blog will take you through the causes of insulin resistance.

Causes of IR
The great majority of people with insulin resistance fall into the acquired categories :-
1. Obesity/Excessive fat (adipose tissue)
One of the most important risk factors for IR is obesity or excessive fat accumulation. Possible mechanisms in different research studies suggest that excessive fat secret substances called Adipokines which are known to impair the targeted Insulin receptor tissues and cause IR.
It has been suggested that obese individuals are associated with a greater rate of fatty acid breakdown and uptake compared with lean individuals, and this higher flux is postulated to be an important mediator of insulin resistance.
2. Lack of movement, exercise
It is well established that exercise is associated with substantial improvement in insulin sensitivity. A single bout of moderate intensity exercise can increase the glucose uptake by at around 40%.The beneficial impact of daily exercise on insulin resistance would be magnified if associated with diminished body fat because exercise can influence the fat deposition in your tissues.
Individuals with diabetes due to insulin resistance can be reversed just by incorporating habitual physical exercise. As excess adiposity in the waistline contributes to insulin resistance, regular exercise assists in reduction of body fat, thus increasing cellular insulin sensitivity.
Indeed, combined with the fact that modest exercise reduces the morbidity and mortality associated with cardiovascular disease and diabetes, it is an effective therapeutic strategy for reducing insulin resistance and, more importantly, improving overall quality of life and wellbeing.
3. Nutritional imbalance
Several nutritional insufficiencies can also ultimately lead to IR. Glucose toxicity or glucotoxicity is a condition leading from untreated high blood sugar. It is accepted that glucose toxicity is involved in the worsening of IR by affecting the secretion of β-cells.
Glucotoxicity not only affects the secretion of pancreatic hormones but also participates in insulin resistance of insulin-sensitive tissues (liver, skeletal muscle, and adipose tissue). Oxidative stress is strongly suspected to be involved in glucotoxicity induced insulin resistance.
High fat intake from n-6 PUFAs are known to worsen and cause Insulin resistance. Largely present in vegetable oils, these n-6 fats cause the adipocytes (fat stores) to signal to peripheral cells to become insulin resistant, as Paul Saladino, a Carnivore MD says. He also states that it is the n-6 PUFAs which initiates the process of IR rather than the carbohydrates.
Moreover, it is worth noting that vitamin D deficiency is very common and may be associated with the pathogenesis of insulin-resistance-related diseases, including obesity and diabetes. Evidence suggests that vitamin D seems to be a regulator of numerous sequential events that are responsible for enabling the pancreatic β-cells to secrete insulin, and thereby to control blood glucose level.
4. Thyroid dysfunction (Hyperthyroidism and Hypothyroidism)
Insulin resistance is defined as a glucose homeostasis disorder involving a decreased sensitivity of muscles, adipose tissue, liver and other body tissues to insulin, despite its normal or increased concentration in blood. Thyroid hormones have a major effect on glucose metabolism along with the development of insulin resistance.
In hyperthyroidism, impaired glucose tolerance may be the result of mainly insulin resistance in the liver, whereas in hypothyroidism the available data recommends that the insulin resistance of peripheral tissues prevails.
5. High inflammation/ elevated inflammatory markers
Development of Insulin resistance is majorly associated with tissue-specific inflammatory responses induced by various pro-inflammatory and/or oxidative stress markers notably pro-inflammatory cytokines such as interleukin-1 beta (IL-1β), interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), numerous chemokines and adipocytokines, as well as glucolipotoxicity.
Chronic exposure of pro-inflammatory mediators stimulates the activation of cytokine signaling proteins which eventually blocks the activation of insulin signaling receptors in β-cells of pancreatic islets.
6. Medications (glucocorticoids, anti-adrenergic, protease inhibitors, antipsychotics)
Treatment with cancer therapeutics such as glucocorticoids, chemotherapy, hormonal therapies and targeted drugs can actually induce insulin resistance. Current literature regarding the incidence of cancer-therapy induced insulin resistance describes the intracellular changes that takes place in insulin signalling pathways and glucose metabolism.
Protease inhibitor use is associated with a potentially serious syndrome of metabolic abnormalities characterized by central adiposity, hypertriglyceridemia, hypercholesterolemia, and insulin resistance.
Other categories of drugs like anti-adrenergic and antipsychotics are also linked to cause insulin resistance.
7. Aging
With increasing age, the body's insulin sensitivity and glucose regulation ability decreases gradually along with muscle wasting. Studies have shown that, compared with younger males (30 years old), older males (65-70 years) have reduced glucose metabolism and decreased expression of skeletal muscle.
The underlying mechanism behind aging and insulin resistance is related to a series of changes in skeletal muscle during the aging process. During skeletal muscle aging, a series of other changes also tend to occur, including mitochondrial dysfunction, fat accumulation, increased inflammation and oxidative stress. These changes can impair skeletal muscle insulin sensitivity and increase the risk of insulin resistance.
8. Smoking
Smoking reduces the effectiveness of insulin, inflames your whole body and also increases the oxidative stress. Nicotine from cigarettes makes the working of Insulin less effective, keeping you in a continued insulin-resistant state. Inflammation occurs when chemicals in cigarette smoke injure cells, causing swelling and interfering with proper cell function, explains the CDC.
Inflammation is one of the key factors responsible for insulin resistance. Oxidative stress is a condition that develops when the smoke inhaled from your cigarette combines with the otherwise healthy oxygen in your body. Your entire body relies on the healthy delivery of oxygen to keep it healthy - and now it’s receiving oxygen that is severely contaminated and can ultimately be the reason behind insulin resistance.

In addition to the above factors, there are a number of unrelated genetic syndromes with associated insulin resistance Myotonic Dystrophy, Ataxia-telangiectasia, Alstom syndrome, Rabson-Mendenhall syndrome, Werner syndrome, Lipodystrophy).
In our work at iThrive we’ve seen that insulin resistance is a silent disease and dangerous and often begins without any evident symptoms. The only way to detect Insulin Resistance is by testing your blood for related parameters. You can consider booking a root cause analysis if you or your loved ones are suffering from insulin resistance and do not have any appropriate direction.
Conclusion
Insulin resistance never happens overnight. It builds quietly, through years of processed foods, stress, disrupted sleep, and a sedentary lifestyle, along with a healthcare system that mostly catches things quite late.
Each and every symptom, right from the fatigue, the weight that won’t move at all, the brain fog, to the cravings, is nothing but your own body waving a flag, and asking you for attention. Insulin resistance is that signal and signals can always be answered.

Whether it’s choosing to walk post dinner instead of just scrolling through social media, or swapping refined oils for clean fats, getting your Vitamin D levels checked, or simply deciding that your health truly deserves the same kind of urgency you offer to everything else.
We’ve literally sat with hundreds of clients at iThrive who came to us completely exhausted and frustrated, and told there was “nothing majorly wrong” only to explore that insulin resistance was quietly running the show. And we’ve seen what happens when they finally understand their own body and in fact started working with it instead of against it.
If any part of this entire blog felt like it was written for you, it definitely was. So go get your levels tested via our root cause analysis and ask us the questions.
References
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