I learned how eating and exercise impact my blood sugar

As it turns out, exercise is good for you. So is sleep, and unfortunately, so are vegetables. 

I’ve heard these health adages hundreds of times before, but they truly began to hit home for me this winter as I tested out a metabolic health platform from the startup Signos. In short, the company offers a subscription service that includes a small continuous glucose monitor (CGM), which you stick on your arm or abdomen, that sends that data to the Signos app which, in turn, aims to help you lose weight by keeping track of your blood sugar.

The subscription price varies depending on the plan you pick. A one-month plan starts at $449, but a 6-month plan starts at about $143 a month if you pay upfront. But services like this, once reserved for diabetics, may soon offer a whole new revenue stream for health companies. Dexcom, for example, recently received FDA clearance for its over-the-counter Stelo product, expected to launch this summer. Meanwhile, Signos competes with other firms like NutriSense, Veri and Levels.

I wanted to get a first-hand understanding of what these glucose monitors are like, so I gave Signos’ latest system, which uses a Dexcom G7 monitor, a try. Here’s what I learned.

Founded in 2018, Signos uses continuous glucose monitors, or CGMs, and an artificial intelligence-powered app to help people better understand their metabolisms. The company gives users personalized insights into how their bodies respond to specific foods and when they should exercise to get the best results for weight loss. 

Glucose is a type of sugar we receive from food, and it’s the body’s main source of energy. A CGM is a small sensor that pokes through the skin to track an individual’s blood glucose levels, or blood sugar levels, in real-time. The sensor is usually worn on the upper arm or abdomen, and it can wirelessly transmit data to a smartphone. 

CGMs are primarily used by people with diabetes since they can help patients get alerted to emergencies. But Signos’ CGM system is meant for average consumers, so it is not intended for diabetes management. Other companies like Abbott Laboratories are also launching consumer-facing CGM systems in the U.S. this year. 

Signos’ platform teaches users how their daily habits like diet, hydration, exercise, stress and sleep affect their glucose and can cause it to spike. 

Glucose spikes occur when the amount of sugar present in the bloodstream rapidly increases. This often happens after eating. In the short term, spikes can cause feelings of lethargy and fatigue, but high blood sugar can lead to more serious health problems like diabetes, heart disease and kidney disease over time, according to the Centers for Disease Control and Prevention. 

Everyone’s glucose levels are variable, so spikes and dips are inevitable, but Signos aims to help people reduce the intensity and frequency of their spikes. The company says that maintaining relatively stable glucose levels can help people improve the health of their metabolism, lose weight and ultimately reduce the risk of chronic disease. 

To get started with Signos, I had to take a quick questionnaire that asked me for some basic biological information and details about my medical history. I submitted my answers for review by an independent physician, and my CGM prescription was approved and began processing for shipment a few hours later.

After a couple of days, my kit arrived in a brown Signos box. It includes an instruction manual, the CGMs, alcohol wipes and athletic patches to put over the CGM once it’s applied. I followed the instructions in the manual and downloaded the Signos app, which prompted me to set up accounts with Signos and the CGM company . 

Dexcom makes the CGMs that Signos uses, though Dexcom’s products are exclusively designed for patients diagnosed with diabetes. Signos is using Dexcom’s CGMs as part of a clinical study approved by an institutional review board designated by the U.S. Food and Drug Administration, which monitors biomedical research involving real people, Sharam Fouladgar-Mercer, Signos’ co-founder and CEO, told CNBC in October. 

Dexcom Ventures also backs Signos as an investor, and the firm participated in the $20 million funding round that Signos announced last fall.  

Signos’ platform works with Dexcom’s G6 CGM and the newer G7 CGM. I tested the platform using the G7, which Signos launched in January. The G6 and the G7 sensors last for 10 days, and I went through three G7s during my trial. 

Once I had set up my accounts, it was time to put on my first sensor, which I was nervous about.

I’m generally fine around needles, though I tend to look away if I have to get a shot at the doctor’s office. The CGM’s needle is small – it looks like someone clicked a mechanical pencil a few times, for comparison – but I can’t say I was excited to stick it into my arm. 

Much to my relief, applying the sensor is easy and painless.

The Signos app walked me through the process step by step, offering a one-minute video and a series of GIFs I could watch. I cleaned the back of my left arm with an alcohol wipe, placed the applicator there, pressed the button on the applicator and popped the CGM, needle and all, right onto my arm. The G7 is white, about the size of a quarter, and maybe half an inch thick.  

I paired the CGM to the Signos app by enabling Bluetooth and scanning the corresponding QR code on my applicator. Once the CGM was applied and paired to my app, I put a purple athletic patch on top to help protect the sensor from tugging, sweat and water. 

It took the sensor about 30 minutes to adjust to my body before it was warmed up and ready to go.

I was worried that the CGM would be painful or cumbersome, but I forgot about it often, and it’s easy to wear normal clothes and jackets over it, even if they have tight sleeves. 

I experienced some sensitivity for a couple days when sleeping on my left side, particularly after changing out the sensor. My upper arm felt a little tender, like there was a light bruise. However, I chose to wear the CGM in the same place on my left arm each time, and I think I could have avoided that sensitivity if I had switched between my left arm and my right arm.

I had never seen or interpreted glucose data before, and I thought the Signos platform did a nice job explaining concepts and breaking them down. The app led me through a series of short articles and activities to get started, like how to log my meals and exercise. 

It also introduced me to the concept of my “optimal glucose range,” which is where Signos wants you to try and keep your glucose levels. Signos starts by setting the upper bound of the range at 120 mg/dL, and the lower bound at 80 mg/dL, but the app’s algorithm adjusts it based on your body’s patterns. My upper bound was eventually adjusted to 126 mg/dL, for instance. 

When you look at the Signos home page, you can see your real-time glucose reading, your glucose level graph (which includes a shaded area to indicate your optimal range), and the percentage of time you’ve spent in the range each day. This could be particularly beneficial for folks who may be prediabetic and want to keep an eye on their levels over time.

Once I got the hang of the basics, Signos prompted me with more activities and articles that helped me experiment and deepen my understanding of my blood sugar. For instance, one activity encouraged me to try exercising right after a meal, and when I did, I saw it drastically reduced the spike I was experiencing. 

Another activity had me try and guess what I thought my glucose levels were at different points throughout the day. I was surprised how quickly I began to understand the correlation between how I was feeling and my current reading. You can skip activities if you don’t want to do them, but on the whole, I found them interesting and useful.  

Signos also has registered dieticians on staff, and users can ask them questions via chat, email or through a phone consultation. I set up a meeting after my first week wearing a CGM, and I found it very helpful. I asked a bunch of questions about my data and the Signos app itself, and I also got some tips about what to try and work on next.

I knew the experience would be personalized, but I don’t think I’ve ever had this much specific insight into what is happening in my body. I found it fascinating to see how I responded to different foods, and there were some surprises.

I frequently eat instant oatmeal for breakfast, for example, and have always thought of it as a relatively healthy meal. But in actuality, I learned oatmeal causes my glucose to spike significantly. On Feb. 9, oatmeal raised my levels from 88 mg/dL to 167 mg/dL. So while it may be a great breakfast for some people, oatmeal isn’t necessarily the best choice for me. 

I was less surprised by my reactions to many other foods, but I still found it valuable to reinforce these concepts with data. Processed foods like chips and sweets caused large spikes in my levels, but fruits, vegetables and protein-rich meals had a much more gradual impact. I eat greek yogurt as a snack a lot, for instance, and I found that it hardly caused my levels to spike.  

It felt powerful to see how my body responded to nutritious food and it definitely made me more conscious of the choices I was making.   

As it turns out, spikes in your blood sugar can be caused by a whole lot more than just food. That was news to me. In addition to logging meals and exercise, the Signos app has a “Tags” feature where you can write notes and select from a list of more than 60 different possible spike-causing culprits. Some of the options include stress, travel, medication, sickness, crying and even a hot shower. 

I learned that my glucose tends to spike while I’m writing a breaking news story (who knew!), and I spend less time in my optimal range when I’m feeling tired. I had a particularly stressful week at work in January, and looking back at my readings, I can definitely tell. 

I found it helpful to visualize how all sorts of different factors, some within my control and some not, could impact my blood sugar. It really drives home the idea that you are affected by the world around you.     

And for bonus points, the CGM is a great conversation starter. 

I found that my friends, family and colleagues were really interested in the device and what I was learning from it. Since it’s not all that common for the average person to wear CGMs yet, I think there was an element of novelty there. 

Finally, it’s easy to take off the CGM when it expires. After the 10 days are up, you simply grab the adhesive and peel it off like a sticker.  

Signos’ user interface is easy to use, but some features were more intuitive than others. 

It took me a few days to learn how to input my sleep, for instance, because I couldn’t figure out how to log the hours correctly. It was also hard to gauge how much detail to use when logging my meals, as I tended to keep my entries to just a few words. I might have gotten more specific insights and fine-tuned my algorithm further if I had more guidance there. 

Additionally, it wasn’t always possible for me to engage with the platform’s alerts and activities, particularly during the work day. 

After eating a meal, I would often get a “Fast Rise” notification from my Signos app, which indicates that a glucose spike is occurring. The notification encourages users to engage in 20 to 30 minutes of “brisk walking” or 10 to 15 minutes of plyometrics, a form of high-intensity exercise, to help reduce the spike. I work in-person at CNBC’s newsroom three days a week, so this often wasn’t realistic for me to do. 

I asked about this notification when I met with the Signos dietitian, and she told me that any movement is beneficial, even if it’s just a quick walk up or down a flight of stairs. I tried to make sure to take a lap around the newsroom once I learned that, but I think it would have been helpful to know upfront, too. 

Subscriptions to Signos are expensive, and for many users, CGMs are not covered by insurance yet. Customers who sign up for Signos can choose a one-month, three-month or six-month plan.

The steep price tag is definitely worth considering. According to its website, Signos said users who have been diagnosed with type 2 diabetes may be able to get the cost of the CGM covered by their insurer. But users who do not have type 2 diabetes may be out of luck. 

The company said some people may be able to use their Health Savings Account reimbursement funds to cover the Signos, but that it “is not responsible for reimbursement in any capacity,” according to the site.  

In other words, users who want to try and reduce the costs of the platform have to try and figure it out themselves. 

I also found myself checking the Signos app frequently, almost like it became another form of social media. This gave me some pause. 

I have been fortunate to have had a relatively positive relationship with food throughout my life, and I’m also not someone who experiences much health anxiety. Even so, I tried to be very conscious of my mindset and attitude toward the Signos platform. I treated Signos like a tool and a learning experience, and I really didn’t want to put too much emphasis on the numbers. 

I knew that approach would be best for me, and it worked well for the most part. However, I did catch myself feeling guilty about large spikes on a few occasions. 

As I noticed those feelings, and how often I was checking the app, I felt like it was pretty easy to see how the platform could end up being harmful for some users’ mental health, particularly if they’ve struggled with body image or eating disorders. 

Signos said all prospective members are asked about their medical history, including disordered eating, in their initial medical questionnaire. If someone is actively experiencing or in recovery from an eating disorder, Signos said the independent physician would not approve them for participation in the Signos program.

The company said it does not recommend any specific eating style, and there are metabolic health coaches on staff to help check in with users about how they feel. 

As with most things, I think trusting yourself is key here. If you don’t think accessing your metabolic data would be good for your mental health, then using a CGM is probably not a great idea. You can also always check in with your doctor to decide if the technology is right for you. 

The Signos experience really depends on you, the user. 

The app isn’t going to do the learning or make lifestyle changes for you, so if you aren’t willing to take the time to log your meals and complete activities, chances are you won’t get much out of the platform. 

As a young and relatively healthy individual, I wasn’t sure what to expect from Signos, but I learned a lot about how my body responds to my diet, sleep, exercise and stress. The CGM is like a little window into what goes on beneath the skin, and I think it’s easy to see why it’s a valuable tool. After just one month of use, I have a deeper understanding of why I feel sleepy, lethargic or energized.

I wouldn’t be surprised if I return to CGM systems at different stages of my life to better understand how I am responding to my nutrition and the world around me.