I Wore a Continuous Glucose Monitor for 2 Weeks—Here’s What I Learned

Devices like Fitbit trackers and smartwatches have helped millions of people keep track of their health and wellness because these devices can help you become more aware of your habits. Plus, you’ll be able to set goals toward improving and maintaining your health and wellness—from getting more steps and exercising more frequently to getting a better night’s sleep, tracking your food, and being mindful of your stress. 

Recently, I was interested to know what my blood glucose trends look like. As a person without diabetes, this is not something I typically monitor. I’m not a fan of needles and didn’t find the idea of pricking my finger multiple times a day all that appealing, either. Nonetheless, as a health professional, I find it interesting to monitor my own health and am always looking for ways to keep tabs on it. A nifty new device made it possible to monitor my blood glucose for a period of two weeks with only one skin prick. 

A New Era of Monitoring Your Blood Glucose 

A standard glucometer is a device that tells you your current blood glucose levels in a moment in time. It works by analyzing a small amount of your blood—usually from a fingertip. On the other hand, a continuous glucose monitor (or CGM) is a device that doesn’t require any pricking or lancets to get your glucose reading. It consists of a sensor, attached to your upper arm, that transmits both an instantaneous glucose level and an eight-hour trend graph when you scan it and upload the data to an app on your phone. A CGM also has the ability to warn you if your sugars are trending high or low. So, a CGM offered me a way to assess my own blood glucose trends without needing to prick my finger every 2 hours, which was certainly a plus. It also allowed me to continuously track my glucose levels throughout the day and night. 

Research using CGM devices has shown there are a variety of factors that are unique to every person, such as weight, genetics, gut microbiome, lifestyle, and insulin sensitivity that determines response to different foods. So, with a CGM strapped to my arm, I set out on my own personal 14-day health experiment. Here’s what  I learned about my body and my health. 

Foods that Caused My Biggest Sugar Spikes

The thing I found most interesting—and probably not all that surprising—was how refined grain products like white rice, breads, and pastries caused my blood sugar levels to spike extremely high. According to the American Diabetes Association, a random blood sugar test taken at any time that shows above 200 mg/dl (11.1 mmol/l) indicates that a person may have diabetes.

But surprisingly (even to a dietitian such as myself) was how fresh coconut juice caused my biggest spikes of glucose level. It’s basically juice, right? And of course, I was choosing the no-added-sugar versions. Although the juice itself is a better choice than a canned soft drink, the high level of naturally occurring sugars was still causing my sugar levels to climb much higher than I was expecting.

Another example was rice. Both white and brown rice resulted in significant spikes, although it’s important to point out that combining it with other foods, like sugar-sweetened sauces, may have contributed to this spike.

The meal that created the most noticeable gradual increase and then decrease in my glucose levels was one of my favorite lunches: scrambled eggs, smoked salmon, avocado, spinach, and cherry tomatoes with two slices of sourdough bread on the side. No real surprises there, as most of these ingredients are very low in carbohydrates, except for sourdough bread, which is a low glycemic index (GI) food. This means that it’s a food the body typically breaks down and digests more slowly; it doesn’t cause big blood sugar spikes. Choosing more low GI foods is recommended for better blood glucose control. 

What Happens When I Skip Breakfast

What I discovered is that my body goes into hypoglycemia (low blood sugar) during sleep. The relationship between sleep and blood sugar levels is complex. Sometimes, I’d wake up wondering if the strange dream I had was a sign that I’d had low blood sugar levels during the night. 

According to the National Institute of Diabetes and Digestive and Kidney Diseases, hypoglycemia during sleep can cause symptoms like nightmares, yelling, and sweating. This probably isn’t an issue for me right now because I don’t have diabetes. But, for someone with pre-diabetes, knowing this may be a symptom of nighttime low blood glucose may help you take further steps to maintain your sugar level. 

For this reason, I eat breakfast as soon as I wake up because my body requires it to fuel up for the day and so I can allow it to function as it should. Skipping for me was a hazard and only led to poor concentration, bad headaches, and hangry (that is, hungry and angry)!

Eating Regular Meals Creates a Rhythm

It was interesting to see that my blood sugar levels dipped when I was approaching my next mealtime. When you’re following a meal routine and your body adapts to it, it’s pretty amazing to see how your body finds a certain rhythm. Research shows how irregular meal patterns can lead to weight gain, increased hunger-related hormones, and ultimately to a metabolic disturbance that may increase cardiovascular risk regardless of your meal frequency. 

I generally eat my meals at similar times most days and the daily ebb and flow of my blood sugar levels reflect this, almost like my body knows when to anticipate its next meal.

Fuelling Post-Workouts

Over the two weeks I monitored my blood glucose levels, I noticed that the sugar spikes following breakfast went down significantly after two hours of high-intensity exercise, which is a great sign because now I know when to fuel myself when I go for a long run or bike ride. This also makes complete sense, because during exercise the body is using the glucose in my blood for energy to fuel my muscles. Now, I always bring along a sports bar or gel if I’m going for an extended or more vigorous workout session. 

Remember not to skip or delay post-workout refueling as it can leave you feeling tired or dizzy, and more severe low blood sugar can cause you to pass out. Additionally, it was great to see how a simple activity like going for a short 15 to 30-minute walk after a big meal helped to stabilize my sugar level.

Remember, Everyone is Different

Overall, it was fascinating to see how my body responds to the food I eat and to know that it’s functioning as it should. It’s reassuring to see that sugar spikes decrease quickly, indicating that I do not have pre-diabetes and that my body is producing insulin as it should. I enjoyed experimenting with different foods to see how they affect my blood glucose levels, and found it  amazing to get this much insight into my personal data. 

But remember, everyone is different. If you’d like to get your own personal view of your blood glucose levels and trends, this is a good way to take a sneak peek into your own body, so you can discover how it is responding to different foods and make healthy changes if needed. 

For more personalized support on keeping blood sugar levels within range, your Fitbit Health Coach is just a click away and is able to help you develop a personal action plan and keep you motivated on your health journey.