If you’ve ever seen someone sporting a small, circular sensor on their upper arm, that's most likely a continuous glucose monitor (CGM). They are designed to help people with diabetes keep a constant eye on their glucose (or blood sugar) level, clueing them in to when they need to eat or give themselves insulin, and helping them track how successful they are at keeping their blood sugar in the optimal range. But these days, the devices are gaining popularity with people who do not have diabetes — people who think that a steady stream of info about their blood sugar can help them make smarter food choices and lose weight. Do they deliver? Here’s what experts have to say.
How CGMs work
CGMs, which are typically worn on the back of the arm, contain a tiny sensor that sits just below the skin and measures the amount of glucose in the fluid between your cells. “Instead of relying on a few fingerstick checks that give you a single snapshot in time, CGMs can provide insight on how your glucose changes throughout the day and night,” explains Dr. Priya Jaisinghani, M.D., a specialist in endocrinology, obesity medicine, and diabetes at NYU Langone Health.
The sensor automatically sends this data to a reader, usually an app on your phone, every few minutes, allowing you to see your glucose levels in real time. It’s normal for the blood sugar to change throughout the day, but for most people without diabetes it stays within a range of 70 to 140 mg/dL. If you have diabetes, the American Diabetes Association recommends staying within 70 to 180 mg/dL for most of the day. “In those living with elevated blood sugars, CGMs can serve as valuable feedback tools by revealing glucose trends and patterns,” says Jaisinghani.
What blood sugar tells you
Blood sugar goes up and down all the time depending on food, movement, stress, and even sleep. Had a chocolate chip muffin for breakfast or sle terribly the night before? You may see your blood sugar go up. Enjoyed a balanced dinner of grilled chicken, quinoa, and veggies? It could stay relatively steady. Went too long without eating or had a super active day? You may see a drop. But if it goes too high or too low, it can signal certain things:
If blood sugar spikes
Eating sugary or carb-heavy foods like candy or a bagel can cause your glucose to quickly climb higher than your optimal range. Frequent spikes can stress your body and zap your energy levels, and over time, this (as well as other factors) can lead to insulin resistance.
Try this: To help bring levels back down, go for a short walk or do some light movement (your muscles use glucose for fuel). Staying hydrated and pairing carbs with protein or fiber at your next meal can also help steady your blood sugar.
If blood sugar dips down
If you skip a meal, exercise for a long stretch (like a tough strength workout, long run over 60 minutes, or HIIT spin class), or take certain glucose-lowering medications (such as insulin or sulfonylureas), your glucose can drop down below 70 mg/dL, a condition known as hypoglycemia. This can make you feel irritable, tired, shaky, and dizzy.
Try this: To bring your levels back up, eat or drink about 15 grams of fast-acting carbs (like a ½ of a medium banana or 1 slice of bread) and recheck your glucose in 15 minutes.
Your CGM can also tell you something called “time in range.” The longer your glucose levels are in your target range, the better controlled your blood sugar is. According to the American Diabetes Association, you’d ideally spend 70% or more of the day in range. This leads to steady energy, better focus, and lower risk of long-term complications.
Why would someone without diabetes wear a CGM?
The allure of all this data for someone without diabetes is that it’s like having a live feed showing you exactly what is happening in your body, at any given time. Biohackers (people who experiment with their body to optimize health, energy, and performance), athletes, and wellness enthusiasts have started using CGMs to gain a better understanding of how different foods, workouts, and sleep patterns affect their blood sugar and, in turn, their energy, hunger, and overall well-being.
The goal is to avoid dramatic spikes and crashes, since those may indicate you’re not eating or behaving optimally for your health. They then use this data to personalize their daily routines, making small, strategic tweaks to what and when they eat, how they move, sleep schedule, and more.
For example, if they notice a sharp spike after eating their morning toast, they might add a source of protein or fiber (like eggs, almond butter, or plain Greek yogurt) the next time. If their levels dip too low after a long workout, they might self-adjust by having a small carb-rich snack like dried mango or dates beforehand.
What does an ideal daily glucose pattern look like?
The ideal daily glucose graph will show gentle rolling hills or waves, with small rises after meals, smooth returns to your baseline, and flat lines overnight. (What you don’t want are sharp peaks and cliffs.) These gentle waves show that your body is responding appropriately to your lifestyle choices, including meals, activity, and rest.
In the morning, glucose should be ~80-100 mg/dL (if you haven’t eaten overnight). Some people experience a small rise in blood sugar (known as the “dawn effect”) as the body releases hormones to get you set up for the day.
Blood sugar naturally rises 20 to 40 minutes after eating, then returns to baseline within two to three hours. For most people, post-prandial (or after meal) glucose should be around 120 to 140 mg/dL. The more balanced your meal — a mix of protein, fiber, and healthy fats — the smaller and smoother your post-meal bumps are. The higher in sugar or refined carbs your meal is, the more dramatic the spikes.
Glucose also responds to activity. Since your muscles use glucose for fuel, glucose can dip slightly during steady physical activity like going on a walk. Intense workouts, however, can cause a temporary rise in glucose, since stress hormones release stored blood glucose.
Overnight, your levels should fall back to baseline and stay stable. However, alcohol or late high-carb snacks may cause big overnight spikes. Overnight dips may mean you didn’t eat enough for dinner or overdid it with exercise.
If your graph looks like high peaks and low valleys, then your glucose is swinging more than it should. Most CGM apps will identify trends for you automatically, but you can always work with an expert like a registered dietitian or another healthcare provider to identify the best ways to balance your blood sugar through the day.
Can tracking blood sugar with a CGM help you lose weight?
It can, but it’s not a guarantee. “Better understanding your blood sugar can provide helpful insights for seeing how your body responds to different foods and meals,” says Caroline Thomason, R.D., CDCES, a registered dietitian and certified diabetes care and education specialist in Virginia. And that spotlight on the inner workings of your body can motivate you to make more balanced food choices, which can then improve glucose control and impact your weight.
When your blood sugar swings dramatically up and down, your body naturally releases more insulin, which can encourage fat storage and make you feel hungrier. Preventing large glucose spikes, on the other hand, can increase satiety, reduce hunger, and eliminate cravings. This awareness can lead to more mindful eating and improved food choices.
Let's say you drink a "healthy" fruit smoothie in the morning — you might notice that it causes a big post-breakfast blood sugar spike. With that feedback, you may adjust your smoothie recipe, adding protein (like plain Greek yogurt, unsweetened protein powder, or nut butter) and fiber (such as chia seeds, spinach, or kale). These small tweaks can lead to steadier blood sugar and longer-lasting energy.
“While I don't think CGMs are a necessity to lose weight, they offer feedback about how your lifestyle choices impact your body, and this, in turn, can lead to healthier habits and potentially weight loss,” says Edwina Clark, R.D., a registered dietitian who has personally tried out CGM herself.
That said, a CGM is only as useful as you make it. You can have all the data, but if you don’t modify your behaviors, you will likely see no change in your health. “Tracking your glucose doesn’t automatically lead to fat loss,” says Thomason.
What the science says about CGMs and weight
This is all great in theory, but what does the research show? It depends if you’re talking about people with diabetes or not. Research does indicate that people with diabetes using a CGM make healthier food choices, including limiting or excluding glucose-spiking foods like sugar-sweetened beverages and white rice. Moreover, people with diabetes using CGMs also report more physical activity, especially after a meal. However, it's unclear whether the general population reaps the same benefits from wearing a CGM.
- A 2024 systematic review found that CGMs can help “modestly” improve blood sugar. For example, users showed a small drop in A1C (your average blood sugar levels over the past two to three months) as well as a 7.4% increase in “time in range” (a.k.a. better blood sugar control) compared to those without CGM data. However, the evidence is limited because only a few studies measured actual lifestyle changes, the interventions varied, and most trials were short-term.
- A 2025 study found that using a CGM in conjunction with individualized nutrition therapy may be beneficial and effective for improving diet and sleep quality in people with prediabetes, overweight, or obesity.
- Some research supports using a CGM in conjunction with diet and activity tracking to improve meal composition and timing, as well as activity, in adults without diabetes. These results are strongest in adults with overweight and obesity and/or with prediabetes.
As you can see, there’s limited evidence connecting CGM use with significant weight loss or lifestyle improvements in people without diabetes. That said, early studies suggest that, as a tool, it may help you make more informed meal and lifestyle choices.
It’s also worth noting that the existing research for usage of CGM in people without diabetes is still in its early stages: Most studies are small, short in duration, and largely funded by CGM manufacturers. Experts are still considering the value of CGMs for the general public, and routine use isn’t currently recommended.
Should you get a CGM to help with weight loss?
A CGM may be helpful if you’re struggling to lose weight and feel like you’ve exhausted every tool in your toolkit, but you should work with a professional like a registered dietitian to help interpret the data.
Importantly, CGMs are not right for everyone. Individuals with a history of disordered eating or obsessive tendencies will likely want to avoid them, as there is a potential for unhealthy behaviors. “For people without diabetes, CGMs can sometimes do more harm than good,” says Thomason. “The constant real-time data can easily lead to food anxiety, obsessive monitoring, or unnecessary restriction.”
The devices are also expensive and often require app subscriptions that incur a large fee. They are not yet F.D.A. approved for use in healthy individuals, so there likely isn’t insurance coverage unless you are diagnosed with diabetes.
5 ways to improve blood sugar without a CGM
While a CGM can be helpful, you don’t need one to keep your blood sugar steady. The real magic still lies in foundational healthy nutrition and lifestyle habits, not the sensor and data. Here are some ways you can support steady blood sugar, and in turn a healthy weight, with or without a CGM:
- Pair complex carbs (fruits, vegetables, and whole grains — all of which contain some fiber) with protein and/or healthy fats to slow digestion and prevent blood sugar spikes. Healthy fats include avocados, nuts, seeds, nut butters, fatty fish like salmon and tuna, and oils like olive oil and canola oil.
- Skip refined carbs and sugary beverages (which trigger crashes)
- Choose high-fiber foods to help you stay fuller longer
- Eat balanced meals at regular intervals
- Stay active! Even “gentle” exercise, like walking, can make a huge difference in promoting stable blood sugar. Aim to walk at least 30 minutes throughout the day.
One great way to stay motivated with these healthy behaviors is to join the WeightWatchers Points Program. It helps you prioritize foods high in protein and fiber and low in added sugar, taking the guesswork out of stabilizing your glucose.
The bottom line
CGMs can offer a fascinating insight into how your glucose behaves throughout the day, but they’re not a guaranteed weight-loss solution. While research suggests that CGMs can help people with diabetes make better lifestyle choices and manage blood sugar more effectively, the jury is still out on the effect they have on people without diabetes.
Sustainable, long-term weight management is still rooted in a healthy lifestyle, including eating balanced meals, regular physical activity, and adequate sleep.
This content is for informational purposes only and does not constitute medical advice, diagnosis or treatment. It should not be regarded as a substitute for guidance from your healthcare provider.