Why Your Brain Fog Might Be a Blood Sugar Problem

Hey Brain Warriors!

Welcome to this new edition of GBA Cognitive Mastery.

Ever feel like your brain is running on 1% battery, even after a full night’s sleep and your third coffee? You're not alone. And no, it’s not just in your head (well… it is, but not in the arrogant way we’ve been taught by your doctor).

For decades, we were told that depression, anxiety, and even bipolar disorder are the result of a chemical imbalance in the brain — cue the serotonin storyline. But recent research suggests there's another key player at the table: how your brain processes energy.

And that starts with how well your body manages blood sugar.

🔋 Brains Run on Fuel, Not Just Feelings

Your brain uses about 20% of the glucose (sugar) in your bloodstream, making it the hungriest organ in your body. But if your brain can’t get glucose in efficiently, or can’t use it properly, things start to fall apart.

Studies show:

🧠 60–80% of people with depression have disrupted glucose metabolism in key brain areas, especially the prefrontal cortex (the “focus & decision-making” center) and the limbic system (the “feelings” center). This often leads to:

• Fatigue

• Brain fog

• Mood instability

🌀 Bipolar disorder and schizophrenia have also been linked to insulin resistance! That’s when your body can’t regulate blood sugar properly, and glucose doesn’t reach brain cells as it should. Imagine trying to power a city on flickering electricity.

This means mental health issues might be less about brain chemicals… and more about brain fuel.

🔄 The Mood–Metabolism Loop

Insulin resistance doesn’t just impact your waistline — it affects your brain’s ability to function.

When your cells become less responsive to insulin, glucose can’t get in. And when the brain doesn’t get enough energy, it struggles to keep up with basic tasks like mood regulation, memory, and attention. Cue:

• Mood swings 😵

• That foggy, sluggish feeling at 3pm 🥱

• Low motivation to do anything (including fixing it) 😩

It becomes a vicious cycle: metabolic dysfunction impacts mood, and chronic stress (which affects cortisol) makes insulin resistance worse. It's like trying to put out a fire by fanning the flames.

👪 What If It’s Not Just ADHD?

If you’re a parent and your child can’t sit still, zones out mid-sentence, or goes from sweet to meltdown after lunch — you’re not crazy, and neither is your kid.

Many children showing signs of ADHD might actually be dealing with blood sugar swings and overstimulation.

Let’s break it down:

🧃 Sugar doesn’t just mess with glucose levels, it overstimulates the brain’s reward system. Add in refined carbs, additives, and constant screen exposure, and the brain is basically on a rollercoaster it didn’t sign up for.

Kids’ developing brains can’t handle these spikes and crashes well. The result?

• Trouble focusing

• Mood swings

• Tantrums (yes, even at 11 years old…)

• Poor sleep

• General chaos

Before rushing to medication or diagnosis, try adjusting how the day starts:

• ✅ High-protein breakfast (eggs, Greek yogurt, nut butter on wholegrain toast)

• ✅ Cut down on ultra-processed snacks

• ✅ Keep the afternoons calm—both food-wise and screen-wise

This doesn't just help them, parents often find their own mental clarity improves too.

Win-win.

🍳 So What Can You Actually Do?

Let’s face it: the modern diet wasn’t built for brain health. But the great news? Your body and brain respond fast when you give them what they need.

Here’s how to start:

• Eat real, whole foods. Especially ones with protein, healthy fats, and fiber.

• Move daily. A brisk walk is enough to improve insulin sensitivity.

• Sleep 🛌. Yes, still the most underrated biohack.

• Calm your nervous system. Meditation, breath work, walk, or even just 10 minutes of sitting without a screen.

• Get tested! If you suspect insulin resistance or blood sugar issues, talk to a functional practitioner.

🔧 Brain Fuel Tip of the Week

Start your day with a breakfast that keeps your blood sugar steady.

Swap the sugary cereal + OJ combo for something with protein, fat, and fibre, like scrambled eggs with avocado and some greens, or chia pudding (using coconut milk 🥛 ) with nuts and berries.

This slows glucose absorption, prevents that mid-morning crash, and keeps your brain sharp and steady. Your mood will thank you. So will your kids 👧 .

That’s it for this week’s brain boost, warriors.

Let me know what resonated, and if you want a part 2 where we dive into how glucose and the gut are also linked to mental health, just hit reply. If you need any help with any of the above, don't hesitate to reach out.

Until next time, keep those neurones firing!

Thierry