Your Blood Sugar Affects More Than Your Waistline
When most people hear the words blood sugar, they probably think about diabetes, weight gain, or maybe that afternoon energy crash after eating too much sugar.
But your blood sugar may also have important implications for something you don't immediately associate with metabolic health:
Your brain.
The brain represents only a small percentage of your total body weight, yet it requires an enormous amount of energy to function. Every thought, memory, decision, and movement requires brain cells to continually produce energy.
That's one reason I've become increasingly interested in the relationship between metabolic health and brain health.
My friend Dr. Annette Bosworth, better known as Dr. Boz, has spent years working with patients struggling with insulin resistance and metabolic dysfunction. In our conversations on the Strong By Design podcast, she's repeatedly emphasized that these aren't simply issues of body weight or diabetes. They can affect how people feel, think, and function as they age.
She's seen older patients come to her complaining that their memory isn't what it used to be or that they simply don't have the mental energy they once had. From her perspective, that conversation has to include the health of their metabolism and their ability to efficiently fuel the brain.
This connection becomes particularly important after 50.
As I discuss in my Complete Guide to Memory Loss After 50, cognitive aging isn't determined by one thing. Movement, sleep, nutrition, stress, social connection, genetics, and metabolic health can all influence the environment in which your brain has to function.
And researchers have become increasingly interested in one metabolic problem in particular:
Insulin resistance.
In fact, the relationship between insulin resistance and Alzheimer's disease has generated so much scientific interest that you've probably encountered a provocative phrase online:
"Type 3 diabetes."
But what does that actually mean?
And does having insulin resistance mean you're destined to develop Alzheimer's disease?
Thankfully, the answer is no.
But understanding why researchers are investigating this connection can teach us something incredibly important about protecting both our metabolic health and our brains as we age.
What Insulin Resistance Means for Your Brain
To understand the connection between blood sugar and brain health, we first need to understand insulin.
When you eat carbohydrates, your digestive system breaks many of them down into glucose, which enters the bloodstream. In response, the pancreas releases insulin, a hormone that helps regulate blood glucose and signals tissues throughout the body to use or store available energy.
In a metabolically healthy person, this system works remarkably well.
But problems can develop when cells become less responsive to insulin. The pancreas compensates by producing more of it to accomplish the same job.
That's insulin resistance.
Dr. Boz does a great job explaining this in our podcast together.
Early on, the body may still keep blood glucose within a relatively normal range but it can require increasingly larger amounts of insulin to do it. That's why metabolic dysfunction can be developing long before someone is eventually diagnosed with Type 2 diabetes.
And this is where the conversation becomes especially important for brain health.
For years, insulin was discussed primarily in relation to blood sugar and diabetes. We now know that insulin also has important signaling functions within the brain, including roles related to learning, memory, and neuronal health. Research into brain insulin resistance suggests that impaired insulin signaling may be involved in cognitive decline and Alzheimer's disease.
But the association is strong enough that researchers have spent years investigating the metabolic characteristics shared by Type 2 diabetes and Alzheimer's. Type 2 diabetes itself has been associated with approximately twice the risk of all-cause dementia, although dementia is complex and influenced by many different factors.
So, Is Alzheimer's Really "Type 3 Diabetes"?
You've probably heard Alzheimer's disease referred to as "Type 3 diabetes."
It's a powerful phrase but it needs some context.
Type 3 diabetes is not an official medical diagnosis. Rather, it's a term researchers have used to describe the metabolic abnormalities observed in Alzheimer's disease, particularly impaired insulin signaling and glucose metabolism within the brain. Research continues to investigate exactly how these processes contribute to the disease.
And that's an important distinction.
We aren't saying that eating sugar causes Alzheimer's or that someone with insulin resistance is destined to develop dementia.
What the research does tell us is that metabolic health and brain health are much more closely connected than we once realized.
That's one reason Dr. Boz puts so much emphasis on improving metabolic health in the older adults she works with. When someone comes to her in their 60s complaining about declining memory or mental energy, she doesn't look at the brain as though it exists separately from the rest of the body.
Neither should we.
The health of your metabolism helps create the environment in which your brain has to function.
And when blood sugar and insulin remain poorly regulated for years, that environment may become increasingly hostile to healthy brain aging.
The Blood Sugar Roller Coaster
One blood sugar spike after a meal isn't the enemy.
In fact, blood glucose is supposed to rise after we eat. And as Dr. Boz demonstrated during our Strong By Design experiment, glucose can even rise temporarily during intense exercise as the body releases stored fuel to meet increased energy demands.
The bigger concern is what happens when large swings in blood sugar become a repeated pattern.
Think about the way many people eat today.
A highly processed breakfast. A sugary coffee on the way to work. Refined carbohydrates at lunch. An afternoon snack when energy crashes. Another large meal at night.
Repeat that pattern day after day, year after year, and the body's metabolic machinery is constantly being asked to respond.
Research has associated greater glucose variability with poorer cognitive performance, particularly in people with Type 2 diabetes. Scientists are also investigating whether repeated glucose fluctuations contribute to longer-term cognitive decline, although the evidence connecting glucose variability specifically to Alzheimer's disease is still developing.
Why the Spikes Matter
Repeated periods of high blood sugar and large glucose fluctuations can contribute to oxidative stress, inflammation, and dysfunction within blood vessels. Those effects matter because the brain depends on an enormous network of healthy blood vessels to continually deliver oxygen and nutrients.
Over time, metabolic dysfunction can create an environment where several problems begin overlapping:
- poorer vascular health
- increased inflammation
- greater oxidative stress
- impaired energy metabolism
And none of those are particularly friendly to an aging brain. Current research increasingly describes this as a cardio-metabolic-brain connection, where metabolic and vascular health influence neurological health rather than operating as completely separate systems.
This is also why I don't think the takeaway should be “never eat carbohydrates” or “every glucose spike is damaging your brain.”
That's an oversimplification.
The more useful question is:
What does your metabolic pattern look like over months, years, and decades?
Are you regularly moving your body and using the fuel you're consuming? Are you maintaining muscle? Are most of your meals built around real, nutrient-dense foods? Are you sleeping well? Or are highly processed foods, inactivity, poor sleep, and constant overeating creating metabolic stress day after day?
That's where this conversation becomes empowering.
Because unlike your age, many of the habits influencing your metabolic health can be changed.
And some of the most effective ways to begin improving them don't require an extreme diet or complicated protocol.
How to Support Healthier Blood Sugar and Your Brain
The good news is that improving metabolic health doesn't require perfection or an extreme diet.
It starts with consistently giving your body a better environment in which to manage the fuel you're consuming.
1. Build Your Meals Around Real Food
One of the simplest places to begin is by reducing the amount of ultra-processed food and added sugar in your diet.
Focus more often on quality protein, vegetables, whole fruits, healthy fats, and fiber-rich foods. These foods provide valuable nutrients while helping create meals that are more satisfying and easier to sustain.
You don't need to fear carbohydrates. You simply want the majority of your nutrition coming from foods that actually nourish you rather than relying heavily on highly refined, processed foods.
2. Put Your Muscles to Work
This one is especially important to me as a strength coach.
Your muscles aren't just there to make you stronger or look better. Muscle tissue plays an important role in glucose metabolism. When you're physically active, working muscles use glucose for energy, and regular activity can improve the body's ability to manage blood sugar.
That's another reason I believe resistance training becomes increasingly important as we age.
Maintaining muscle gives you somewhere productive to put that fuel.
3. Walk More
Never underestimate something as simple as walking.
A short walk after a meal gets your muscles working at exactly the time glucose is entering the bloodstream. Even a 10-minute walk after dinner is a practical starting point recommended by the CDC for becoming more active and supporting blood-sugar management.
You don't need to turn every walk into a workout, either.
Walk the dog like I do every morning. I have two Australian Shepherds that require a ton of exercise so I’m always outside with them. Take your spouse outside after dinner for some fresh air and an evening stroll. Hike on the weekends. Play a fun game of pickleball. Park farther away from the store entrance. Get up from your desk throughout the day for a glass of water or walk around the office building after lunch.
Remember, movement adds up.
4. Protect Your Sleep
Sleep and metabolic health are closely connected.
Consistently getting too little sleep can negatively affect glucose regulation and insulin sensitivity, which gives us yet another reason to stop treating sleep as optional.
Seven or eight hours spent sleeping isn't time wasted.
It's part of taking care of your metabolism and ultimately your brain.
Keep the Big Picture in Mind
None of these strategies operate in isolation.
Nutrition matters.
Muscle matters.
Movement matters.
Sleep matters.
And that's really the larger message. Supporting healthier blood sugar isn't about obsessing over every bite of food or every glucose reading. It's about building a lifestyle that helps your body manage energy effectively for decades to come.
For a deeper look at how these habits work together with balance, cognitive stimulation, purpose, and other factors that influence the aging brain, I've covered the complete picture in my Complete Guide to Memory Loss After 50.
Your Metabolic Health Is Part of Your Brain Health
The connection between blood sugar and brain aging reinforces an important truth:
Your brain is not separate from the rest of your body.
Taking care of your metabolic health today may help create a healthier environment for your brain in the years ahead. And that's only one piece of the much larger brain-health puzzle.
If you'd like to explore how movement, strength, balance, sleep, nutrition, purpose, and other lifestyle factors work together to influence cognitive health, read my Complete Guide to Memory Loss After 50.
Give Your Brain Additional Nutritional Support
Healthy habits should always come first. But targeted nutritional support can complement those habits.
That's where Neuro-Thrive comes in.
We formulated Neuro-Thrive with ingredients selected to support several aspects of healthy brain function, including Bacopa Monnieri, Alpha-GPC, PQQ, Vitamin D3, GABA, and B vitamins.
Think of Neuro-Thrive as another tool in your brain-health toolbox, not a replacement for movement, nutritious food, quality sleep, or improving your metabolic health.
If you're serious about supporting your memory, focus, and cognitive health as you age, start with the fundamentals and let Neuro-Thrive help support the foundation you're already building.