If you’ve ever felt like your body is working against you when it comes to weight loss, you’re not imagining it. For many of us, especially those dealing with weight gain, stubborn belly fat, energy crashes, or unrelenting cravings, the problem isn’t lack of willpower, in fact in clinic, I have always been amazed at the level of resilience and willpower most of my patients have when it comes to diet, so much so, I am often telling them they are not eating enough. So, what is the root cause of the problem? Well, as the title of this series suggests, it is always hormonal.
In this first part of our four-part hormone series, we’re shining the spotlight on one of the most misunderstood hormones in your body: insulin. If you’ve ever wondered why cutting calories doesn’t seem to work anymore or why you’re constantly hungry despite eating "healthy," keep reading. This hormone is key to unlocking long-term, sustainable weight loss.
Meet Insulin: Your Blood Sugar Boss (and Fat Storage Manager)
Insulin is a hormone made by your pancreas, released every time you eat carbohydrates (and, to a lesser extent, protein). Its main job is to move glucose, the sugar your body makes from food, out of your bloodstream and into your cells. Glucose gets stored in your muscles and liver as glycogen, ready to be used for energy later.
Sounds helpful, right? It is. But here’s the kicker: once your storage tanks are full, insulin starts directing any extra glucose to your fat cells. This is why we refer to insulin as the storage hormone. And that means when it’s constantly elevated, your body is in storage mode, not burn mode.
Now, here’s where it gets really interesting. Insulin has a hormonal opposite called glucagon, the body’s natural fat-burning hormone. The pancreas also makes glucagon, and it’s released when your blood sugar is low or during fasting. Its job is to unlock your stored fuel, converting glycogen back into glucose, and breaking down body fat to use for energy.
But here’s the catch: Glucagon can’t do its job if insulin is hanging around. The moment you eat, insulin levels rise, and glucagon is suppressed. It’s like a hormonal seesaw: when insulin goes up, glucagon goes down.
This dynamic is crucial to understand. You physically cannot burn stored body fat while insulin is elevated, because your body is still in storage mode. For fat burning to occur, insulin levels need to decrease, allowing glucagon to rise and take effect.
This is a major reason why it’s so difficult to lose weight when your insulin levels are high; your fat-burning system never gets a chance to switch on.
Why the Standard Western Diet Isn’t Helping
Let’s call this out clearly: the typical Western diet is a blood sugar rollercoaster. Breakfast cereals, toast, fruit juice, mid-morning biscuits, sandwiches, crisps, pasta, and sugary snacks all cause sharp spikes in blood glucose, forcing your body to release insulin again and again throughout the day.
And here’s something most people miss: all carbohydrates break down into glucose, not just sugar. That includes so-called healthy choices like brown rice, oats, bananas, and even root vegetables. Your body doesn’t care whether the glucose came from a fizzy drink or a jacket potato; it still raises blood sugar and triggers insulin.
Another crucial factor is the obsession with low-fat foods. Most low-fat products are, by their very nature, higher in carbohydrates and often lower in protein and healthy fat. This combination leads to faster digestion, larger blood sugar spikes, and increased insulin production, keeping you firmly in fat storage mode. These foods may appear low in calories, but they do little to stabilise hunger, meaning you’re more likely to snack or overeat later.
Yes, you might lose weight on a low-fat, high-carb, low-calorie diet, but typically only in the short term. Why? Because your metabolism adapts. Your body gets more efficient at running on less fuel, and the weight loss stalls. Worse still, muscle can be lost in the process, further lowering your metabolic rate.
If you’re constantly topping up your glucose tank, your insulin remains active, glucagon stays switched off, and you never give your body a chance to access its fat stores. You’re always storing—never burning.
Insulin Resistance: When the System Breaks Down
Insulin resistance happens when your cells stop responding properly to insulin’s signal. The pancreas attempts to rectify the issue by releasing even more insulin, aiming to force glucose into your cells.
This creates a vicious cycle:
- More carbs = more glucose
- More glucose = more insulin
- Cells stop responding = more insulin again
- Excess glucose = more fat storage
High insulin also blocks fat burning. Your body can’t access its fat stores while insulin is active. Think of it like a switch: insulin on = fat storage. Insulin off = fat burning.
This is why even eating a small snack, like a banana or handful of crackers, keeps fat burning switched off if insulin is being constantly triggered throughout the day.
Insulin and Your Weight: The Downward Spiral
High insulin levels do more than just store fat. It also:
- Increase cravings, especially for sugary, high-carb foods (thanks, ghrelin!)
- Interfere with leptin (your "I’m full" hormone), so you don’t feel satisfied after eating
- Disrupt sleep, which worsens cravings and weight gain
- Increase inflammation, which is linked to almost every chronic disease
So no, you’re not weak. If your hormones are out of balance, your body is hardwired to keep you hungry, tired, and stuck.
What Causes Insulin Resistance?
A few major contributors:
- Diets high in refined carbohydrates and sugars
- Sedentary lifestyle
- Poor sleep
- Chronic stress (which raises cortisol, another insulin disruptor)
- Inflammation
- Perimenopause and menopause
- Nutrient deficiencies (magnesium, chromium, B vitamins)
Some people also have a genetic predisposition, and it’s closely linked to conditions like PCOS, fatty liver disease, and type 2 diabetes.
How Do You Know If You Might Be Insulin Resistant?
Some common signs:
- Constant hunger
- Cravings for carbs or sugar
- Energy dips after eating
- Weight gain (especially around the middle)
- Trouble losing weight despite trying everything
- Skin tags, especially around the neck or underarms
- Brain fog
Blood tests such as fasting insulin, HOMA-IR, or even a glucose tolerance test can confirm what’s happening, but your symptoms are often a helpful clue.
What Can You Do to Lower Insulin?
Here’s the good news: insulin resistance is highly responsive to diet and lifestyle changes. Even small improvements can make a big difference.
- Lower Your Carbohydrate Intake
This is the #1 tool for reducing insulin. Prioritise non-starchy vegetables, healthy fats, and protein. Avoid sugary snacks, white carbs, and processed food. Even wholemeal bread can spike blood sugar for many. - Don’t Fear Fats (the Right Ones!)
Fat doesn’t trigger insulin the way carbs do. Good fats (like olive oil, nuts, seeds, oily fish, avocado) help you stay full and stabilise blood sugar. Just steer clear of ultra-processed, inflammatory seed oils. - Prioritise Protein
Protein helps regulate appetite, supports lean muscle, and keeps you full. Aim for at least 20-30g per meal. Use an app, such as MyFitnessPal or Nutracheck, which will show you how much protein and carbs you are consuming per day. - Time Your Eating
Avoid constant grazing. Give your body gaps between meals. Intermittent fasting (with guidance) may help switch from storage to fat-burning mode. - Get Moving
Exercise helps shuttle glucose into muscle cells without needing as much insulin. Strength training is particularly effective. - Sleep and Stress
Lack of sleep and elevated cortisol levels contribute to increased insulin resistance. Prioritise restorative sleep and manage stress with breathwork, meditation, walking, or grounding. - Check Your Nutrients
Magnesium, chromium, and B vitamins play essential roles in blood sugar balance. A personalised supplement plan can help if you’re depleted.
Final Thought: It's Not Just About Willpower
This isn’t about blaming yourself or counting every calorie. Hormonal weight gain, especially insulin-driven, requires a completely different approach than what most of us have been taught.
It’s not about eating less and moving more. It’s about eating smart, balancing hormones, and resetting your body’s natural rhythms.
In our next article, we’ll examine leptin and ghrelin, the powerful duo that regulates your appetite, cravings, and feelings of fullness (or lack of). If your hunger feels out of control, this one's for you.
By Sarah Flower, Nutritionist.
