Blood sugar

The Top 5 Things I Learned from Wearing a CGM for 14 Days

Most of my clients have heard how I completely fan girl over the work of dietician, Lily Nichols, RD. She has written a must-have pregnancy nutrition book called Real Food for Pregnancy and also a book for women diagnosed with Gestational Diabetes called Real Food for Gestational Diabetes.

I was inspired to use a continuous glucose monitor (CGM) after a blog written by Lily about her own self experiment with the device. I do not have diabetes and I hope I don’t seem glib while talking about my time with the Freestyle Libre CGM. If anything, it gave me an appreciation for those people I have encountered, who do have diabetes, specifically Type 1 Diabetes (T1DM) where monitoring their glucose comes down to life and death.

Being a data driven person, I have always had a fascination with tweaking my nutrition to “see what would happen”. One thing I have noticed in myself is a propensity to get lightheaded or shakey. I’ve often wondered if it was because my glucose was too high or too low? Those symptoms can happen with either. My fasting morning glucose has always been in the low 80’s and my Hemoglobic A1c has also always been below a 5. All of these are great numbers with no indication of a blood sugar issue. However, this does not tell me how well I do day to day with different foods.

How did I Get my Device?

Freestlye Libre Testing Supplies

Freestlye Libre Testing Supplies

A finger poke glucometer is widely available without a prescription. However, a Continuous Glucose Monitor is not. I am not sure why these require a prescription, but it may be due to supply and demand. In order to get my GCM, my dad who is an MD had to prescribe it for me. I did not use my health insurance for it since I do not have diabetes and ended up paying about $42 per sensor (I ordered 2 - each used for 2 weeks and then disposed of) and $130.64 for the reader which is a one time purchase. The reader is not necessary since there is a free app you can use, but especially if you have to monitor your glucose, it is beneficial to have in case your phone is not available or charged. The reader can also be used as a standard glucometer, so I also got the strips and lancets. Walmart was the only pharmacy in my area (Grand Rapids, MI) that could order this device. They did not have it in stock, so it did take a couple of days from the time the prescription was called in to the time I could pick it up.

The sensor was easily and painlessly inserted into the back of my arm (this is the required placement). I was aware of it at first, but as time went on, I forgot it was there! I was worried working out or sleeping on that side would be uncomfortable, but I didn’t even notice it.

So here is what I found out:

Daily Patterns

Daily Patterns:

This chart shows what may glucose did on average over the 14 days of monitoring. The black line is the average and the blue gradient shows all 14 days superimposed on one another. From this chart I could see that on average my glucose stay between 90 to 100 mg/dL. I set my glucose target range to be between 80-140mg/dL which is considered the “healthy range”. I was happy to see I that 77% of the time I stayed within that range.

Time in Target

Time in Target:

There were a few times I was out of range. As I had suspected, I do have some episodes of low-ish blood sugar. I was interested to see that it happened at nighttime. As my husband well knows, I am a big time sleep talker and walker. I hypothesized that these glucose dips may be contributing to those symptoms. The 1% of time that I went over 140 was mostly due to eating some extra desert that I knew would spike me. Here were the situations:

March 5th

March 5th

March 5th:

I spiked to 150 after a homemade dinner of split pea soup. Although this isn’t super high, my thought was that it was from not having a lot of protein + fat to offset the carbohydrates from the peas and other veggies.

March 9th

March 9th

March 9th:

This was my dad’s birthday! We had chocolate cake after dinner and you can see the up and down spikes I experienced afterwards starting at about 7:30pm. This is where I felt shakey and jittery. It looks as though my insulin caused my glucose to quickly go down after eating the cake and then more glucose was broken down and so on.

March 11th

March 11th

March 11th:

March 10th looked pretty good. I wanted to show this graph because of my biggest spike I experienced. I had 2 chocolate chip cookies right before bed with no other macros. This really shows how differently glucose is handled when eaten with protein and fat (as was the case with the birthday cake) and when carbs are eaten alone (naked carbs as Lily says!). I had the hardest time getting to bed that night, so apparently my body does not like glucose levels at 180mg/dL.

March 13th

March 13th

March 13

The last abnormal reading I wanted to show was from March 13th. My husband and I sometimes have a mid-week date night and this was one of those days. We went to a brewery and in the spirit of St. Patrick’s Day, we had corned beef sandwiches and beer.

The reason I want to show this is to help you understand why alcohol consumption is a predisposing factor for conditions such as Type II Diabetes (T2DM). From the previous graphs, you saw how my glucose would rise and then make its way back down. With alcohol consumption, I saw a super quick drop that made me hypoglycemic. I went from a level of 160mg/dL to about 60mg/dL in less than a 2 hour range. Alcohol can be bad for blood sugar because it causes your pancreas to release insulin. If that amount of insulin does not match your sugar intake, it can cause you to become hypoglycemic. The problem is when alcohol consumption is frequent and/or excessive, that is a lot of excess insulin being released which can cause insulin resistance in your cells leading to pre-diabetes or diabetes.

Snacking vs Eating 3 Meals

Snacking all day of March 10th

Snacking all day of March 10th

Snacking Scenario

What about the argument of eating small meals throughout the day (aka snacking) or just focusing on 3 square meals per day?

On the day I snacked my glucose was constantly up and down. I even saw some of my lowest lows. I have to say from a subjective standpoint, I didn’t feel as energetic and felt hungry more often.

My snacks were essentially small meals all with protein/fat/carb macros that were whole food nutrition.

3 Square Meals on March 12th

3 Square Meals on March 12th

3 Square Meals

A normal day is focused on 3 square meals (thanks to the Crossfit 616 Nutrition Challenge for helping me fine tune this!). My meals are typically made of 25% protein (about 2/3 cup) from an animal source, 25% (also about 2/3 cup) starchy carb usually from fruit, squash, potato, rice, or quinoa, 50% (at least 1.5 cups) low starch veggies like zucchini, salad, etc, and 2 TBSP healthy fat like 1/4 avocado, nut butter, seed or raw nuts, or olive oil drizzled on salad as a part of dressing.

The days I did that, I had a great insulin response and glucose control. I felt energized and never “hangry”.

So What are the Five Things I Learned?

  1. Eating 3 well rounded meals with no snacks makes me feel the best.

  2. Alcohol contributes to insulin resistance because it releases excess insulin from your pancreas.

  3. Eating “naked carbs” with no protein and fat spikes my glucose and definitely should not be done right before bed (hello insomnia!).

  4. On average, my blood glucose was well controlled. It stayed between the 80-140 mg/dL range and even when it did spike, it was back within range well within the 2 hour limit that we look at when diagnosing diabetes. The shakey-ness I experience was experienced when my glucose was falling quickly - not when I was at my lowest or highest. Also, my night time sleep talking and walking may be due to blood sugar dips.

  5. Exercise and stress affects blood sugar too! I would test myself when I was feeling stressed and I would notice an increase in sugar even if I hadn’t eaten (stress hormones release sugar for energy). For exercise, I noticed after aerobic work (row machine, speed walk or run, biking) I would have a more of a drop in blood sugar right after working out because my cells were using glucose for energy. Anaerobic work such as weight lifting and high intensity work had less of a noticeable effect on my blood glucose levels. However, studies show there are long term benefits over the 24 hours following high intensity exercise in blood glucose levels.

After doing this experiment, I thought about how I could use this with my clients. I truly feel that anyone can benefit from seeing what they are eating on a glucose graph like this. Seeing it made me more motivated to do better with my nutrition and help explain what I was feeling. This made me feel empowered about my nutrition choices. I also think about Gestational Diabetes, a condition of diabetes experienced by some women during pregnancy. Lily Nichols specializes in this field and has evidence based research to support HbA1c testing during the first trimester to predict if a woman will experience blood sugar issues later in her pregnancy. If diagnosed with any type of diabetes, most people test their glucose by pricking their finger upwards of 4 times per day. Wearing this device would be so much better than doing that! Hopefully it will be more widely distributed and available to clients.

The last thing I want to leave you with is the experience of having T1DM from someone who has dealt with it from childhood. Maddie is a student of mine at Davenport University and after hearing about my experiment with the CGM, she graciously shared what it has been like to have T1DM.

There are days where you don’t understand why your body is doing this, and even days where you wish you weren’t alive. It has taught me to care for my body better, by limiting my carbohydrate intake while also exercising daily. This disease, although causing me to grow up a lot sooner than most kids my age, somehow has changed my life for the better. 

General Info about Type 1 Diabetes

Madeline Guis


I was diagnosed on December 21, 2010 at the age of ten-years old. At first my mom thought I had the flu and decided to bring me into my pediatrician’s office. Upon blood tests and a urine sample, my doctor told my mom and I that my glucose level was so high that it didn’t even read on their meters. I was sent immediately to Helen DeVos Children’s Hospital, where I would spend the next two days there. Over the next two days I was instructed on how to keep myself alive using insulin injections, counting carbs, and regularly monitoring my glucose levels. As of 2019, the doctors at Helen DeVos still aren’t sure how the virus attacked my pancreas.

  I currently take two different kinds of insulin. A short-acting insulin, also called Humalog, which is needed when I eat any carbs or if my glucose levels are too high. The other insulin is a long-acting insulin that runs across an entire day. I take 36 units of this insulin, called Lantus, every evening at 9 PM which helps regulate my glucose levels over the course of a 24-hour period.

In December of 2017, after quite a bit of discussion with my endocrinologist and my parents, it was decided that trying a CGM (continuous glucose monitor) might be beneficial. I began using a Dexcom G5, and since then it has greatly enhanced my control over this disease and allowed a small amount of freedom. The CGM has lowered my A1C (average glucose level taken over 3 months) drastically in just a year of using my Dexcom.

  I am fortunate to have two hard working parents who have provided for my needs as a diabetic, but the haunting prices still wrap around my brain daily. I worry for the day that I may not have full coverage for my monthly boxes of Humalog or Lantus, which currently cost upwards of $1200 each. Without Humalog I can die within 48 hours of my last dose, even without eat carbohydrates as a result of my liver producing sugar daily. As a Type 1 Diabetic you have to be mindful about the amount of sugar or carbohydrates you consume per meal. I tend to eat a very limited amount for breakfast, usually a sandwich or grilled chicken (whatever is served at caf), and then I don’t tend to have dinner until about 10:45 at night due to work.

  Many see this disease as an immense burden and many actually say, “at least it’s not cancer.” Although that may be true, that it’s not cancer, it still doesn’t have a cure, and it requires constant monitoring and care. As a Christian, I thank God every day that he has kept me alive 18 years already, but this doesn’t mean that I LOVE this disease per se. This disease is hard work, and it’s not for the faint of heart (or blood and needles). I’m thankful that despite having this autoimmune disease that currently has no cure, I am able to live my life knowing that it has made me into a stronger human being.

  There are days where you don’t understand why your body is doing this, and even days where you wish you weren’t alive. It has taught me to care for my body better, by limiting my carbohydrate intake while also exercising daily. This disease, although causing me to grow up a lot sooner than most kids my age, somehow has changed my life for the better.