In this article, we’ll explore the important connection between blood sugar and brain health.

I used to think blood sugar and brain health were completely separate problems. Then I started digging into the research, and what I found changed everything about how I approach brain health.

Here’s something that stopped me in my tracks: some researchers are now calling Alzheimer’s disease “Type 3 Diabetes.” Not as a metaphor. As a description of what’s actually happening in the brain.

If you’re a woman in perimenopause or postmenopause dealing with brain fog, memory slips, or just feeling like your mind isn’t as sharp as it used to be, this connection between blood sugar and brain health might be the missing piece you haven’t considered.

Why Your Brain Cares So Much About Blood Sugar

Your brain is only about 2% of your body weight. But it uses roughly 20% of your glucose. Let that sink in for a second.

Your brain is essentially an energy hog. And when something goes wrong with how your body handles glucose, your brain feels it first and hardest.

In 2008, researchers Suzanne de la Monte and Jack Wands published a paper that reshaped how we think about cognitive decline. They showed that the brains of Alzheimer’s patients had become resistant to insulin, similar to what happens in Type 2 diabetes, but localized in the brain. They called it “Type 3 Diabetes.”

This isn’t fringe science anymore. The connection between metabolic health and brain function is now one of the most active areas of Alzheimer’s research.

The Menopause Factor: Why This Hits Women Harder

If you’ve noticed your blood sugar feels harder to manage since perimenopause started, you’re not imagining it.

Estrogen plays a direct role in how your cells take up glucose. There’s a protein called GLUT4 that acts like a door, letting glucose into your cells. Estrogen helps keep that door working properly. When estrogen drops, that door doesn’t open as easily.

Research from 2006 published in PNAS showed exactly how estrogen receptors regulate GLUT4 in muscle tissue. A 2022 review by Yasmine Doust and colleagues examined sex differences in brain insulin resistance. The takeaway? Women face unique challenges here, especially during the menopause transition.

This is why so many women notice brain fog, energy crashes, and weight changes during perimenopause even when they haven’t changed anything about their diet or lifestyle.

The Problem With “Normal” Blood Sugar

Here’s what frustrates me about standard lab work: your fasting glucose can look perfectly normal while insulin resistance is already developing behind the scenes.

Your body is smart. When cells start resisting insulin, your pancreas pumps out more insulin to compensate. For years, this keeps your glucose numbers in the “normal” range. But all that extra insulin is doing damage you can’t see on a basic metabolic panel.

This is why I always recommend asking your doctor about fasting insulin, not just fasting glucose. It’s often the earliest warning sign that something’s off.

Labs Worth Discussing With Your Doctor for Blood Sugar and Brain Health

Basic starting point: Fasting glucose, HbA1c, lipid panel

Digging deeper: Fasting insulin, full thyroid panel including TSH, free T3, free T4, and antibodies

The full picture: ApoB, hs-CRP, vitamin D, B12, iron studies, hormone panel

5 Ways to Support Blood Sugar and Brain Health

The good news? You have more control over this than you might think. These aren’t complicated interventions. They’re practical changes that can make a real difference.

1. Put Protein First

Most women aren’t eating nearly enough protein. Research suggests aiming for 0.7 to 1 gram per pound of your ideal body weight daily. That’s probably more than you’re getting now.

Protein helps stabilize blood sugar, supports muscle mass (which matters for glucose metabolism), and keeps you satisfied longer. Start each meal with protein before moving on to carbs. The order you eat foods in actually affects your glucose response.

For women over 40, hitting what researchers call the “leucine threshold” matters. That means getting about 3 to 4 grams of leucine per meal, which translates to roughly 25 to 30 grams of protein. This is what triggers muscle protein synthesis, and it becomes more important as we age.

2. Eat More Fiber

Fiber slows down glucose absorption, which prevents the blood sugar spikes that stress your brain. But it does something else too: it feeds the bacteria in your gut that communicate directly with your brain through the gut-brain axis.

Vegetables, legumes, nuts, seeds. Get them in at every meal if you can.

3. Eat Different Colors

This sounds simplistic, but the science backs it up. Different colored vegetables contain different phytonutrients that protect your brain in different ways. Purple foods have anthocyanins. Orange foods have beta-carotene. Green foods have sulforaphane.

You don’t need to memorize which compound does what. Just make your plate colorful and you’ll cover your bases.

4. Walk After Meals

A 2022 meta-analysis found that light walking after meals was more effective than standing alone in improving blood glucose response. You don’t need to power walk. A casual 10 to 15-minute stroll works.

This is one of those interventions that costs nothing and actually works. Your muscles use glucose when they contract, pulling it out of your bloodstream without needing extra insulin.

5. Consider Your Eating Window

Dr. Dale Bredesen (author of The Ageless Brain), whose work on cognitive decline prevention has been influential in this space, developed something called KetoFlex 12/3. The basic idea: go 12 hours overnight without eating, and finish your last meal at least 3 hours before bed.

You don’t have to go full keto. The framework emphasizes plant-rich eating with enough healthy fats and protein to maintain mild ketosis, which may provide an alternative fuel source for brain cells that aren’t using glucose efficiently.

Should You Try a Continuous Glucose Monitor?

CGMs used to be only for diabetics, but that’s changed. The FDA has approved over-the-counter options like Dexcom Stelo and Abbott Libre Rio for people who don’t use insulin. Even the CDC acknowledges that some people use CGMs for general health optimization.

I’ve used one myself. It was eye-opening to see how different foods affected my glucose in real time. But I’ll be honest: it also became a source of anxiety for me. I found myself obsessing over every spike.

My advice? If you try one, set an endpoint before you start. Use it for 2 to 4 weeks to learn about your body, then take the data and move on. It’s a tool, not a lifestyle.

The Bottom Line on Blood Sugar and Brain Health

Your brain’s ability to use glucose efficiently isn’t just about preventing diabetes. It’s about protecting your cognitive function for decades to come.

The connection between metabolic health and brain health is especially important for women navigating perimenopause and postmenopause. The hormonal shifts we experience make us more vulnerable to insulin resistance, but they also give us a reason to be proactive.

You don’t need to overhaul everything at once. Pick one thing from this article and try it for a week. Maybe it’s putting protein first. Maybe it’s a walk after dinner. Small changes compound over time.

Show Sponsor

FullScript Dispensary – sign up with my dispensary for a special discount.

Want to Learn More?

I created a free guide titled “The Brain Fog Solution: Your Guide to Mental Clarity During Menopause.” It goes deeper into the strategies I use with my coaching clients. Download it at healthylifeapproach.com.

This post is based on an episode of The Healthy Life Approach podcast. Listen to the full episode for even more detail on the research and practical strategies.

References

1. de la Monte SM, Wands JR. Alzheimer’s Disease Is Type 3 Diabetes-Evidence Reviewed. J Diabetes Sci Technol. 2008;2(6):1101-1113.
2. Doust YV, et al. Insulin Resistance in the Brain: Evidence Supporting a Role for Inflammation, Reactive Microglia, and the Impact of Biological Sex. 2022.
3. Barros RP, et al. Muscle GLUT4 regulation by estrogen receptors ERbeta and ERalpha. PNAS. 2006.
4. Buffey AJ, et al. The Acute Effects of Interrupting Prolonged Sitting Time in Adults with Standing and Light-Intensity Walking on Biomarkers of Cardiometabolic Health in Adults: A Systematic Review and Meta-analysis. Sports Med. 2022.

Other Resources

Postmenopausal Estrogen Decline and the Link for Alzheimer’s Risk

Estrogen: Powerful Benefits for Brain and Memory

Disclaimer:

Kristen Beasley is a certified functional medicine, nutrition, and brain health coach, not a licensed physician. This content is for educational purposes only and is not medical advice. Always consult your healthcare provider before making changes to your diet, exercise, or health regimen.

Listen to The Healthy Life Approach podcast on Apple Podcasts, Spotify, or wherever you get your podcasts.