Is Insulin Resistance Secretly Sabotaging Your Weight Loss?

We all know the feeling: you try to lose weight, only to have your efforts derailed by a relentless hunger, stubborn fat or a lack of results. Losing weight is that one elusive goal we all hope to achieve at some point during our lives. Despite cutting calories, following restrictive diets and hitting the gym regularly, the number on the scale doesn’t budge. Does this sound familiar? If so, the hidden culprit behind your weight loss struggles could be insulin resistance.

This common barrier to weight loss, and predecessor to diabetes, is estimated to affect up to 40% of individuals worldwide. Insulin resistance affects how your body processes and stores fat, which can make it more difficult to maintain a healthy weight and support metabolic function. Keep reading to learn what insulin resistance is, how it impacts fat metabolism, and the science-backed strategies that can help improve insulin sensitivity and support your long-term health.

What is insulin and what is its role in the human body?

To understand insulin resistance, you first need to understand what insulin is, and its role in glucose metabolism in a healthy individual. Insulin is a hormone produced by the pancreas, functioning to regulate blood glucose.

At a very basic level, your body is made up of billions of cells, each with their own, unique role. Regardless of the type of cell and what its function is, they all have one important thing in common: they require fuel to perform their duties.

This fuel is called glucose, the end product of the carbohydrates you consume. Once in the bloodstream, glucose travels to your cells, but it can't enter on its own. Your cells have built-in protective mechanisms that tightly regulate what gets in and what stays out..

To make sense of glucose metabolism, and understand the role of insulin, let’s use a simple analogy. Imagine glucose molecules floating around your blood, ready to fuel the functioning of the cells they enter. Now imagine your cells as factories, each with a specific specialised job, and locked doors guarding the entrance.

The rise of glucose molecules in your blood (referred to as high blood glucose), activates a guard with a key to the factory’s door. This guard is insulin, and its job is to open the cell door and let the fuel in.

Initially, the guard’s key turns smoothly in the lock, and the door opens to allow glucose to enter and fuel the cell. But over time, and with frequent spikes in blood sugar, the lock starts to wear down and the key doesn’t open the door as effectively as it used to. This is basically what happens in insulin resistance. Regular high blood glucose levels trigger the release of more and more insulin, effectively making the cell “resistant” to its action.

Unaware of the high glucose levels in your blood, the cells experience “starvation” due to the lack of fuel entering the cells. In response, cells will initiate processes that will alert you to eat more in order to gain access to more fuel.

This is the start of a vicious cycle. Over time, glucose levels in the blood continue to increase gradually, and more insulin, more “guards” are released to attempt to open the doors to the starved cells.

What is insulin resistance & how do you know if your insulin levels are high?

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The repeated secretion of insulin in response to high glucose levels over time, leads to a cycle of persistently elevated insulin levels, eventually contributing to the development of diabetes. But before reaching this point, it is worth knowing that this increase in circulating insulin causes the body to store fuel in the form of fat.

Unfortunately, insulin resistance doesn’t have many specific and obvious symptoms that would cause you to notice a red flag. Early signs might include feelings of fatigue, stubborn weight gain, or persistent sugar cravings. But for most, insulin resistance goes unnoticed until their next blood tests reveal a pre-diabetic state.

In fact, many people never hear the words “pre-diabetes”. Instead, they go straight from the finger-prick sugar test at the GP’s office that was “just fine”, to a diabetes diagnosis and a prescription for Metformin.

To avoid this and take charge of your own health, it is worth asking your doctor to run specific blood tests. The most useful test is the HbA1C, which is a good indicator of your average blood sugar levels over the last two to three months, rather than the “spot” result provided by a random glucose test. After making some lifestyle changes, request a follow-up test to gauge your body’s response.

These lifestyle modifications are well-worth adopting, especially considering the detrimental effects of high insulin on your health.

The effect of insulin resistance on your body and health.

Elevated insulin levels trigger the storage of energy as fat, inhibiting the body’s ability to burn fat for fuel. This weight gain tends to present as visceral fat - the harmful type that accumulates in your midsection and around your vital organs.

A study conducted in 2022 demonstrated that insulin-resistant individuals lost less fat on a calorie-restricted diet, than those without it. This suggests that, even at a caloric deficit, insulin resistance might significantly impair your ability to lose fat. In addition to the increased diabetes risk, insulin resistance also contributes to the development of heart disease and non-alcoholic fatty liver disease.

A 2023 study also showed that high insulin levels not only worsen your metabolic health and risk of developing chronic disease, it also drives inflammation in the body. Chronic inflammation, in turn, creates an environment where serious conditions, including cancer, are most likely to thrive.

The good news? Much of this can be changed by making a few consistent and sustainable changes to your lifestyle. Research-backed lifestyle modifications for addressing insulin resistance and improving your body’s ability to burn fat.

Combating pre-diabetes or diabetes typically follows a clinical framework, and your doctor will recommend a strategy based on this, once a diagnosis is made. The first step in this treatment plan is “lifestyle modifications”. This step is often under-utilised due to historically low compliance by patients. By making the necessary lifestyle changes early, you may avoid the need for medications such as Metformin.

Here are 7 lifestyle strategies to help you improve your insulin sensitivity:

• Adopt a clever carbohydrate strategy: Swap out high glycemic index (GI) carbs for slower-releasing ones. As a general rule of thumb, consume carbs with a GI less than 50. A quick google search will tell you the glycemic index of carbs.

• Learn how to differentiate between carbs, proteins and fats: We often over-indulge in carbohydrates because of misleading “high protein” labels on our foods. Empower yourself with basic nutrition knowledge to balance your macronutrient consumption. Pure, whole-protein foods contain all nine essential amino acids your body needs. They are primarily found in animal-based sources like meat, poultry, fish, eggs, and dairy. Fats are oils, nuts, butter, dairy products and avocados. Use this simplified tool to figure out which foods are carbohydrates based on a process of elimination.

• Increase your fiber intake: A 2023 study found that increasing dietary fibre not only enhances satiety, but also improves insulin sensitivity. Low GI carbs are often the ones higher in fibre, making a whole-food diet a smart two-in-one strategy.

• Try fasting or timing your meals better: Insulin levels decrease during times of fasting, and aligning meals with your natural circadian rhythm may further improve glucose control. The old saying: “Eat breakfast like a king, lunch like a prince, and dinner like a pauper”, aligns perfectly with your natural circadian rhythms. Your body also has an increased ability to metabolise glucose earlier in the day.

• Lower blood glucose, and therefore insulin, by moving more: All activity is fueled by glucose. Whether you do cardio, resistance training, or pick up a sport, make it your mission to move more. A 2024 study showed that muscles absorb glucose without relying on insulin. Incorporate resistance training into your routine to build more muscle, potentially increasing glucose-control.

• Sleep enough and stress less: According to a 2022 study, poor sleeping patterns disrupt glucose metabolism and raise insulin levels. Aim for 7-8 hours of consistent, high-quality sleep to improve your circadian rhythms overall.

• Manage your stress levels: Stress releases cortisol, a hormone that worsens insulin resistance and increases appetite. Combine stress-relieving activities with exercise through hiking or pilates.

If insulin resistance has been sabotaging your weight loss efforts, the good news is that the condition is often reversible without the need for medication. Start with small, consistent lifestyle changes that gradually lower your insulin levels, and you might just uncover a healthier, leaner version of yourself.