Glucose and Brain Function: The Fuel Your Brain Needs to Function
You know about carbs and blood sugar, but have you heard of how they impact brain health? You’ve probably heard the term “glucose” (a kind of sugar) and, depending on where you’ve been getting your nutrition information, you might have some mixed feelings about it. But here’s the truth: your brain loves glucose. In fact, it needs it.
Glucose: Your Brain’s Preferred Fuel
Your brain is one of the most energy-demanding organs in your body, using up about 20% of your total energy every day. And guess what its preferred energy source is? Glucose. Unlike other organs that can use fat for energy, your brain relies primarily on carbohydrates - broken down into glucose - to keep things running smoothly. (Yes, your brain can also use ketones for energy, but this is an inefficient process and can have other downstream effects. For someone who is generally healthy, carbs should be the primary source of fuel for your brain).
When you eat carbs, your body breaks them down into glucose, which then travels through your bloodstream to your cells and organs, including your brain. Once glucose reaches its destination, it’s used to produce ATP (adenosine triphosphate), which is the energy currency of cells. This energy helps power everything from concentration and memory to problem-solving and emotional regulation.
What Happens When Your Brain Doesn’t Get Enough Glucose?
Have you ever felt foggy-headed, irritable, or worn down when you’ve gone too long without eating? That’s your brain struggling to function without enough glucose. When blood sugar levels dip too low (a state called hypoglycemia), you might experience:
Brain fog or trouble focusing
Mood swings or irritability
Dizziness or headaches
Feeling sluggish or unmotivated
On the flip side, chronic high blood sugar levels - like those seen in prediabetes, diabetes, and insulin resistance - can damage nerve cells and impact cognitive function over time. It’s all about balance.
Finding the Right Balance
Rather than fearing glucose, sugar, or carbs in general, the key is giving your body and brain steady, reliable energy by focusing on nutrient-dense, fiber-rich carbohydrate sources. Some great options include:
Whole grains like oats, quinoa, pasta and barley
Fruits - fresh or frozen, whichever kind you like! (though raspberries and blackberries are fiber powerhouses!)
Starchy vegetables like sweet potatoes and squash
Legumes like lentils, beans, chickpeas
Pairing these with protein and healthy fats can help slow down digestion, providing your brain with a steady flow of glucose instead of a rollercoaster-like wave of sugar spikes and crashes.
The Bottom Line
Your brain is working hard for you every single day, and it needs proper fuel to function at its best. Instead of fearing carbohydrates, think of them as essential brain food. Giving your body balanced, wholesome meals will not only support your brain function but also help you feel your best throughout the day (aka not hangry).
So, next time you’re feeling mentally drained, instead of blaming “sugar,” ask yourself: Have I eaten enough to fuel my brain today?