Insulin Resistance: The "Silent" Culprit Behind Fatigue, Sugar Cravings, and Stubborn Weight Gain

Q: What does insulin resistance feel like?

- Persistent fatigue, especially after eating - Constant sugar cravings - Elevated triglycerides - High blood pressure - Even symptoms of depression

Do you feel tired after eating? Do you crave something sweet all the time, even right after a meal? Are you struggling with stubborn belly fat that won't budge no matter what you try? It might not be a matter of "willpower" — it could be insulin resistance, a condition affecting millions of people who don't even know they have it.

As an Associate Professor of Nutrition and editor of the international scientific reference book The Glycemic Index (CRC Press, 2019), I've spent years studying and publishing on this exact topic: how diet affects our blood sugar and insulin — and how we can take back control. Let's look at what's really happening in the body.

The journey of sugar through your body

When we eat carbohydrate-containing foods — bread, rice, pasta, fruit, sweets — our digestive system breaks them down into glucose, which enters the bloodstream. As blood sugar rises, the pancreas releases insulin, the key hormone that "unlocks the door" of cells so they can absorb sugar for energy or storage. When blood sugar drops, the liver releases stored glucose, keeping a steady supply — particularly important for the brain.

This balance is elegant... until it's disrupted.

When the system gets "tired": What is insulin resistance?

Over time, muscle and other cells can stop responding properly to insulin. This is often — though not always — linked to excess visceral fat, the fat stored around internal organs. The result? Both blood sugar and insulin remain elevated after meals. Over time, the pancreas becomes exhausted from overproducing insulin, paving the way toward type 2 diabetes.

What does insulin resistance feel like?

Persistent fatigue, especially after eating
Constant sugar cravings
Elevated triglycerides
High blood pressure
Even symptoms of depression

Insulin resistance is also common in women with polycystic ovary syndrome and in overweight or obese children. Unfortunately, it creates a vicious cycle: insulin is an anabolic hormone, so its overproduction promotes abdominal fat storage — which in turn worsens insulin resistance further.

Diagnosis is made through simple fasting blood tests (glucose and insulin), which show how much insulin the body needs to keep blood sugar within a normal range.

The good news: Diet is your most powerful tool

The most effective treatment is weight loss — particularly of visceral fat — through a combination of diet, exercise, and, when needed, medication. On the dietary side, three strategies make the biggest difference:

A reduction of roughly 500 calories/day
Consistent meal timing
Choosing foods with a low glycaemic index and glycaemic load

Glycaemic Index (GI): The "health report card" of carbohydrates

We used to simply divide carbohydrates into "simple" and "complex" — but this classification ignores how they actually affect our blood sugar. In 1981, the Glycaemic Index (GI) was developed, and it remains today the most reliable way to classify starchy foods — a topic to which I've devoted a significant part of my academic career, including editing the international reference book on the subject.

GI ranks carbohydrates on a scale of 0–100 based on how quickly they raise blood sugar:

High GI (e.g., white bread) → rapid digestion, sharp blood sugar swings
Low GI (e.g., whole rolled oats) → slow, gradual rise in blood sugar → less demand for insulin → a "less overworked" pancreas

Low-GI examples (<55): oats, multigrain bread, bulgur, apples High-GI examples: white and wholemeal bread, potatoes, watermelon

The scientific evidence is clear: frequent consumption of high-GI foods is linked to an increased risk of type 2 diabetes, cardiovascular disease, obesity, age-related macular degeneration, and colorectal cancer. In contrast, low-GI foods help with blood sugar control and weight loss.

(For those who want to dive deeper, the book "The Glycemic Index" — Philippou E. (ed.), CRC Press, 2019 — brings together thousands of relevant studies.)

Glycaemic Load (GL): Where quantity comes into play

GI alone doesn't tell the whole story — the amount of carbohydrate also matters. Glycaemic Load is calculated by multiplying a food's GI by the amount of carbohydrate in a serving:

Low GL (≤10): apple, orange, kidney beans, black beans, lentils, milk, cashews, peanuts
Medium GL (11–19): whole-grain basmati rice (¼ cup), oats (1 cup), bulgur (¾ cup), multigrain bread (1 slice), whole-wheat pasta (1¼ cups), sweet potato (90 g)
High GL (≥20): baked/fried potato, processed breakfast cereal (30 g), sugary drinks (330 ml), couscous (1 cup), white rice (1 cup)

The takeaway

Insulin resistance isn't a life sentence — it's your body's signal that something needs to change, and diet is one of the most powerful tools you have.

📚 If you'd like to learn more, subscribe to my YouTube channel ΄Elena Philippou Nutrition and Health', where I share evidence-based nutrition videos in both Greek and English.

You can watch videos on Insulin Resistance (ιn English), Αντίσταση στην Ινσουλίνη (in Greek), Πολυκυστικές Ωοθήκες - Polycystic Ovaries (in Greek) and Your Blood Glucose is Normal - but is it really? (in Εnglish).