The Surprising Brain Health Lessons From Wearing a CGM

Deborah Kan is an award-winning journalist and founder of Being Patient. In this “Thought of the Week” column each Friday, she highlights one of the key stories shaping the future of brain science. 

Dear readers,

A while back, I tried wearing a continuous glucose monitor (CGM), a small device with a hairlike sensor that sits on your arm and tracks how your blood sugar changes in real time throughout the day. I ordered it out of curiosity. I am a runner, and I wondered if all the pasta and carbs I eat on a regular basis were spiking my glucose in ways I couldn’t see. 

Surprisingly, pasta barely moved the needle. Cherries sent it soaring.

Grapes did too. A handful of what I’d always thought of as a healthy snack would spike my levels quickly, and I’d walk around the block a couple of times or run up and down the stairs to bring them back down. The reason, it turns out, makes sense. As a runner, my muscles use carbohydrates efficiently. The pasta gets absorbed and burned. The concentrated natural sugars in fruit hit my system differently. My body’s response to food was not what I assumed, and I had no way of knowing that without the monitor on my arm.

This matters beyond what I eat for lunch. In our Being Patient interview with Dr. Ben Bikman, a cell biologist who has spent his career studying the relationship between insulin and the brain, he explains that the brain is one of the most insulin-sensitive organs in the body. 

When cells become chronically resistant to insulin over time, that disruption doesn’t stay peripheral. It reaches the brain. Insulin resistance is now understood to be associated with the inflammation, impaired cell signaling, and neurodegeneration we see in Alzheimer’s disease. Some researchers have gone as far as describing Alzheimer’s as a metabolic disease of the brain. 

What the CGM showed me was that glucose dysregulation doesn’t always look the way we expect. It isn’t only about sugar and sweets. It’s about how your particular body handles what you eat, and that picture is different for everyone. The monitor gave me something a routine physical never could: a real-time view of my own metabolic response, specific to me, on an ordinary day.

In my view, understanding your glucose metabolism is one of the most practical things you can do for your long-term brain health. The information is available now. Most of us just haven’t thought to look.

If you want to understand more about how insulin resistance connects to cognitive aging, start with our conversation with Dr. Bikman. 

With hope,

Deborah