5 Lessons I Learned from Wearing a Continuous Glucose Monitor This Week

This week, I strapped on a Continuous Glucose Monitor out of curiosity, but also out of a deep desire to understand how my body, especially how my brain and hormones, are responding to my daily routines and eating habits. What I uncovered in just a few days was both fascinating and validating. As a practitioner and someone who eats mindfully, I wasn’t expecting any surprises. And yet, data has a way of always keeping us honest. Here are five lessons I learned that may resonate with you or surprise you, especially if you’ve been working on your metabolic health for a while. 

The first lesson hit me right after waking up: my blood glucose spikes in the morning, even before my caffeine. This is part of what’s called the cortisol awakening response. As cortisol rises in the early morning hours to help us wake up, it also signals the liver to release stored glucose into the bloodstream. This is an in-built mechanism designed to help us feel alert and energized. But if you’re already dealing with insulin resistance or high stress levels, this cortisol-induced spike can feel like a false start to the day, especially if followed by a carb-heavy breakfast. In my case, even without eating, the spike was evident. It reminded me that our stress hormones are intricately tied to our blood sugar regulation. 

The second surprise was more reassuring: my morning coffee didn’t budge my blood glucose.  For years, I’ve heard mixed messages about whether coffee, especially black coffee, might spike blood sugar through its stimulant effect on cortisol. But in my case, it had no significant impact. I did drink it with a splash of heavy cream, and I suspect the fats in the cream helped stabilize the response. This makes sense as fats delay gastric emptying and reduce the glycemic impact of whatever else is consumed. It was a reminder that bio-individuality matters, and that not all caffeine reactions are created equal. It also confirmed that my nervous system is pretty balanced in the morning, and my adrenals aren’t over-responding to simple stimuli like caffeine. This was a game changer for me. 

The third insight came from my meals or rather the lack of dramatic changes after eating. Because I’ve been in ketosis for a while, my postprandial glucose remained incredibly steady. This is a reflection of metabolic flexibility and an efficient fat-adapted state. Even when I ate something with a higher carbohydrate load, my body handled it gracefully. What this tells me is that consistent, low-carb living trains the body to be less reactive to food thus improving inflammation. There’s less blood sugar volatility, and this translates into steadier energy, fewer cravings, and better focus. For anyone on a ketogenic or low-carb plan, this data can feel like a real payoff moment.

What did raise my glucose however was exercise, but in a good way. This was my fourth lesson. Exercise triggered a glucose rise not because of carbs, but because of a sympathetic nervous system response: the classic “fight or flight” mechanism. As the body prepares for physical exertion, it releases glucose for immediate fuel. This isn’t a bad thing at all. In fact, it’s a sign of a well-functioning system. But it also reminds me that interpreting CGM data requires context. A glucose spike during or after exercise is not the same as a spike from a muffin; it’s purposeful and often followed by a rebound effect that brings glucose back down efficiently.

The final lesson was perhaps the most personal: anytime I had even a slight dip in glucose overnight, I would wake up  suddenly. I’ve known the science behind it but seeing it really made it real for me. Blood sugar dips can signal the brain that fuel is low, triggering a wakefulness response to protect us. If you’re waking at 2 or 3 a.m. and struggling to fall back asleep, it may not just be anxiety but it also might be hypoglycemia. This was a powerful reminder of how night time stability matters just as much as daytime. And, of course, when I did test sugar on a night with dessert my glucose soared. Sugar, as expected, is not my friend. It left me with higher levels for longer, disrupting sleep and making me feel sluggish the next day.