What Blood Sugar Tracking Reveals About Your Overall Health

The devices were originally designed for people with diabetes who require insulin, but in recent months, the Food and Drug Administration (FDA) cleared the first over-the-counter CGMs for people who do not take insulin. Since then, two companies have released monitors that can be used by anyone, including people who don’t have diabetes.

As people who write and think about preventive health all day, we wanted to understand what CGMs can tell us about our lifestyle choices and whether it makes sense for healthy people to use them at all. To do this, we conducted a test where we wore CGMs for a month. You can see what we learned below.

The two monitors on the market for non-diabetics are the Stelo from Dexcom and the Lingo from Abbott. The sensors attach to the arm like a sticker and use a tiny painless needle, which measures the interstitial fluid between cells to estimate blood glucose. They then transmit data wirelessly to your smartphone or watch, which displays real-time updates. (The apps can alert you to glucose spikes, which can be disconcerting at first, but they also provide educational info to help you interpret the data!)

The research is still evolving on the use of CGMs in non-diabetics. While we know that high blood sugar increases the risk of heart disease for people with diabetes, there is less evidence about the health effects these monitors have on other people. Studies of non-diabetic people using CGMs have largely found that their blood sugar stays in a normal range most of the time, for example.

Some doctors say having access to this data can motivate people to eat well and exercise. “Being able to see how different foods affect your blood sugar in real time can be incredibly informative,” says Dr. Gabrielle Page-Wilson, Director of Endocrinology and Metabolic Health at the Atria Health Institute. “Data from a CGM can provide insights and identify trends to help shape healthy habits now before metabolic issues occur,” she adds.

There’s a huge potential market for these devices. About three-quarters of Americans have overweight or obesity, and more than one in three adults (almost 100 million people!) has prediabetes, the vast majority of which is undiagnosed. While Dr. Page-Wilson cautions that CGMs aren’t a diagnostic tool, they could help people at higher risk for diabetes monitor their blood sugar and detect trends.

Other groups that could benefit are optimizers or high-performance athletes. In addition to watching out for glucose spikes, athletes can use CGMs to keep their sugar—and thus energy—from dropping too low during a workout.

For our trial, we each wore Stelo sensors for about a month. We first watched how our glucose responded to our normal routines, and then spent a few weeks experimenting, which gave us some key insights:

• People react very differently to glucose: One tester, for example, tried whole-grain sourdough bread from two different bakeries, and ate them with the same topping: unsweetened peanut butter. One of the breads prompted major spikes; the other caused barely a blip. Another tester experienced a rapid rise in blood sugar followed by a sudden drop after eating naked carbs, resulting in what might be called a “crash” or fatigue.
• Sugars hide in interesting places: One of our testers saw her biggest spike after eating a bowl of chicken and bean soup from a healthy lunch spot. Another tester’s biggest spike came after a protein bar labeled “paleo.”
• Try combining foods: One strategy that worked well for us was combining carbs with other macronutrients. Eating protein and high-fiber foods like vegetables before carbs at each meal can slow digestion and steady glucose levels.
• Pay attention to lifestyle factors: Sleep, stress, exercise, and even the menstrual cycle can affect glucose levels. Sometimes exercise or stress can lead to a temporary spike in blood sugar, for instance, but doctors say the real concern would be if a behavior, such as a consistent lack of sleep, raises your baseline glucose over time.
• The trends are what matters: Every spike is not a problem, Dr. Page-Wilson says. “You don’t want to pathologize things that are normal.” When most people eat carbohydrates, their blood sugar will increase—and this is totally normal as long as their blood sugar comes back down within about two hours. Rather than worrying about each time our blood sugar went up, we found it more useful to identify which foods or habits—like scarfing lunch too quickly or eating carbs on an empty stomach—led to blood-sugar spikes.

When our month was up, we stopped using the device. While we also plan to try the Lingo this year, doctors typically say people without diabetes don’t need to keep using a CGM beyond a limited trial.

One reason is cost: These over-the-counter sensors are unlikely to be covered by insurance, and they cost just under $100 for a month’s worth of wear.

Doctors also worry that watching glucose levels fluctuate could make some people worry unnecessarily or promote a disordered relationship with eating.

For our testers, once we learned not to worry about each normal up and down, we saw that small changes that felt manageable could have a significant impact. Tweaks like eating fiber or protein with our carbs or walking around after a meal did help keep our glucose from spiking too high, and the experience emphasized the importance of a good night’s sleep, too.

Tracking glucose offered a sense of control, which felt empowering. But it also highlighted the need for more research on continuous glucose monitoring among the general population.

This article is part of Atria’s Future of Health newsletter. Subscribe here.