Surprising things I learned as a nutritionist wearing a CGM

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We sat down with Rachael Wilcox, a University certified nutritionist to ask about her experience wearing a continuous glucose monitor (CGM). She had a few realizations which show that even for a nutrition expert and health aficionado, there’s always something new to learn. Check out her thoughts, and find out why she believes all of us should be monitoring our blood glucose, even if we’re not diabetic.

Tell us about wearing the CGM. When did you wear it and what was it like?

Recently I’ve been wearing a continuous glucose monitor (or CGM) while eating and exercising as normal. I attached the device to my body then ate, exercised, and slept as I normally would. By using the CGM I was able to recognize what I need to change around my diet and lifestyle to be the healthiest I can be. Here’s what I learned from this valuable experience. 

Why did you use a CGM? 

I have a natural interest in how food and exercise impact my body. Using a CGM seemed like an easy and effective way to get raw and real data on how my lifestyle choices affect my blood glucose levels. The top three things I was most interested in were:

  • How will my daily habits influence my blood glucose?
  • How does stress impact my blood glucose levels? 
  • What was going on with my blood glucose when I felt tired or irritable?

Why do blood glucose levels matter? 

Blood glucose (or, as some people say, blood sugar), comes from the food we eat. How much blood glucose levels change depends also on what, when, and how much we eat or drink. When our blood glucose levels are too high for too long, our cells cannot absorb it, causing a problem.. This increases our risk of developing chronic diseases such as diabetes and heart disease. Blood glucose also affects our energy, mood, and sleep. 

Did it hurt when you put the CGM on?   

I’ll be honest, when I heard the word needle, I immediately thought “this is going to hurt.” So naturally, I was nervous about putting it on. I read the detailed instructions, meticulously followed the step-by-step instructions. Then “click”, I attached the CGM device to my upper arm, and guess what? NO pain! I did not feel a single thing and I was relieved about that. 

Moving forward, for the first few days I was aware the device was there. Not in a painful way, but as in I could feel it stuck to my skin, and I tried not to bump it. But for most of the time, I forgot about it and it’s as if it became a part of me. 

How did your friends react to you wearing the CGM? 

“No, I don’t have diabetes...”

On day 3 of wearing my CGM, I went hiking with a friend, and when she saw me wearing the CGM, she responded with a concerned look on her face and asked me if I had diabetes. I explained why I’m wearing the CGM, and the consequences of not knowing how my body responds to food. It turned out to be a positive and educational discussion about all things food, blood glucose, and the future of self-care.

The truth is, at first I was a little self-conscious about wearing the CGM. I was nervous my friends would think that I had developed diabetes or that I was taking my health care “too far”. What helped me move past this is owning my decision that I am doing this for my health, whether people understood it or not.

After all, it’s my body and I’m the only one responsible for how I take care of it.

What kinds of things can you test using a CGM? 

Using a CGM, you can measure: 

  • Your blood glucose levels
  • How certain foods and food combinations affect blood glucose
  • The impact of stress on blood glucose
  • The effects of exercise on your blood glucose

What did you learn as a nutritionist from wearing a CGM? 

I am not only a nutritionist but a general health enthusiast. I can say that I eat a well-balanced variety of whole foods, exercise regularly, and sleep fairly well. But even I notice sometimes after a meal I can feel tired, sluggish, irritable, and get brain fog. I know that I have a sweet tooth (think dates, fruit smoothies, and dark chocolate), these are not “unhealthy” foods, but they are sweet. And they can spike our blood glucose. But, oh boy, little did I know how much. Especially fruit smoothies. Let’s just say, my time using a GCM has been full of many lightbulb moments.  

Here are two that stand out: 

1. How stress and lots of carbs affect my blood glucose levels 

Until now, I only knew that stress and blood glucose are connected. But I, by all means, did not know how much. 

Let me describe a situation of mine, which may sound familiar to you: I had a stressful start to the day due to my mile-long “to-do” list. But even on these days, I know not to skip my breakfast. 

I had my regular gluten-free bread with honey, banana, and almond butter. When I checked my blood glucose I couldn’t believe it. It spiked - big time! This left me feeling irritable and running on what felt like nervous energy for the next 2-3 hours. 

Then the blood glucose dropped and I was very hungry and tired. I was in a rush, so I had a protein-rich smoothie for lunch and went for a walk in the afternoon. By the afternoon I was so hungry and craving high sugar foods. (I guess you’ve been there too.) So I ate gluten-free pasta for dinner, but I was hungry again at 9 pm. 

I reflected and noticed that after what felt like a long and stressful day, I couldn’t seem to feel satisfied, my blood glucose was still high and I had trouble sleeping. For nearly the whole day, I was a bit of a stressed mess.

What was going on? 

We’ve all heard it before, stress triggers the ‘fight or flight’ response in our body. This response causes the stress hormones (cortisol and adrenaline) to run through our body, which then triggers glucose to dump into your bloodstream. This all happens fast and is a biological design to prepare for action (like run away from a tiger).  

Nowadays a tiger chase is unlikely, but this stress response can be triggered by all manner of day-to-day things such as work deadlines, challenging conversations, or even watching some sad news on television. 

The bad news is that chronic stress levels over a long time are not good. They can cause a decrease in insulin secretion, which then leads to continuously elevated blood glucose levels. 

Lowering stress in our life can take time and dedication, but it’s possible. It’s especially helpful to be able to ‘see inside’ our body when this is happening. Understanding our blood glucose can be key to help manage and reduce stress because we can see a direct cause and effect. 

This can empower us and help us to learn what increases and decreases our stress levels, and in my case this is true. I saw that on days where I was not stressed, my blood glucose remained relatively within a target range.

2. The connection between food combination and my blood glucose levels  

In contrast to my experience above, I had one day where my blood glucose stayed within the target range for 90% of the time. How did this happen? 

On that day, I halved the amount of honey on my toast, added some extra almond butter, and opted for no banana (but strawberries). I also ate a boiled egg for breakfast. And afterwards, I felt great! No spike, no tired and cranky vibes, and I felt full until lunchtime. 

I can see how much better I feel when I don’t experience those blood sugar spikes, and I’m a much nicer person to be around too.

There is no doubt that the order and combination in which we consume food are vital for maintaining balanced blood glucose. 

Science shows us that certain nutrients help slow down the digestion/breakdown of food in the body. For example, eating a handful of almonds before a banana, or enjoying a boiled egg before some dark chocolate. By slowing down the digestion of carbohydrates, the sugars enter the bloodstream more slowly, which results in a lower blood glucose spike, and we feel much for it!

Did you change your eating habits initially because you knew that a sensor was "controlling" you? 

It's tempting to adjust my lifestyle to try and get better results, but I decided to stick to my normal eating habits. By staying authentic, I was able to get a realistic account of how my day-to-day lifestyle affects my blood glucose. This also now provides me with a baseline to track my progress in the future if I make changes to my eating habits.

What adaptations did you make once you started seeing what was negatively affecting your blood glucose?

I learned that my delicious morning smoothie blend is causing a significant spike in my blood glucose. And as tasty as it is, I felt lethargic and hungry within 1-2 hours.

So I changed the recipe to combat the blood glucose spike. 

I opted for no honey, reduced the amount of fruit, and added in more protein powder, coconut yogurt, and chia seeds. The results were mindblowing - I felt physically better, and my blood glucose levels were more stable. And besides the benefit for my blood glucose, it also tasted yummy!

It still raised my blood glucose, a bit higher than recommended, but I am learning how to adapt to it. To me, it was just super interesting how much small changes in food intake can actually impact my blood glucose, and my physical well-being. 

What was happening in your body when the spike occurred?

After eating food, the sugar from that food was broken down into glucose and other simple carbohydrates and then released into my bloodstream, hence why my blood glucose spiked. 

Blood glucose spikes happen when our blood glucose rises and falls quickly (below the level you had before eating). This explains why I felt so tired[1] and hungry after eating high-carb meals,[2] such as gluten-free pasta. 

Too many ups and downs a day will negatively impact my health in the long run, because they can promote the development of diseases such as type 2 diabetes.[3] 

What lifestyle changes would you make now? 

  • Focus on food combinations. 
    • For example, eating a handful of nuts before a piece of fruit. 
    • Change the composition of my morning smoothie. 
  • Reduce my stress levels by spending more time in nature even when the days are getting colder, or do some pilates.

I know that these changes will have an impact on my health in the long run, and just focusing on one or two small changes is manageable for me. In prioritizing my health, it is easier to make these changes. I am especially excited about using the CGM to track and monitor the results. This will help me stay focused and allow me to celebrate my successes. 

Key findings from my experience: 

  • My blood glucose is affected by fruit (for me it’s especially monitoring the amount of fruit I eat)
  • Stress impacts my blood glucose throughout the day
  • The higher my blood glucose rose after food, the more tired, foggy, and moody I felt afterwards
  • Food combinations matter when it comes to stabilizing blood glucose
  • My body responds better to lower carb, higher protein foods, like eggs, nuts and meat.

    Any advice you would give to others considering wearing a CGM?

    Go in with a plan and figure out what you would like to test and take notes about the key things that you learn.

    Be ready to change 1 - 2 things in your lifestyle. This will keep things simple and achievable, and there is nothing like feeling you've reached your goals.

    If you’re ready to make improvements to your health, definitely try wearing a CGM! 

    It’s so enlightening to understand what’s going on inside your body. You’ll get a whole new appreciation and understanding of how your body is responding to your lifestyle, anywhere and anytime.


    [1] Sommerfield AJ, Deary IJ, Frier BM. Acute hyperglycemia alters mood state and impairs cognitive performance in people with type 2 diabetes. Diabetes Care. 2004;27(10):2335-2340. doi:10.2337/diacare.27.10.2335

    [2] Wyatt P, Berry SE, Finlayson G, et al. Postprandial glycaemic dips predict appetite and energy intake in healthy individuals [published correction appears in Nat Metab. 2021 Jul;3(7):1032]. Nat Metab. 2021;3(4):523-529. doi:10.1038/s42255-021-00383-x

    [3] Hall H, Perelman D, Breschi A, et al. Glucotypes reveal new patterns of glucose dysregulation. PLoS Biol. 2018;16(7):e2005143. Published 2018 Jul 24. doi:10.1371/journal.pbio.2005143