Glucose Monitoring, Blood Sugar And Weight Loss: Why It’s The Key To Losing Weight

There’s more to achieving a happy, healthy weight than just counting calories.
blood sugar and weight loss | glucose weight | CMG for weight loss

Article Summary: CGMs for Weight Loss 

There are few things more frustrating than hitting a weight loss plateau. You’re doing everything right, eating less, moving more, generally sticking to The Plan. But no matter how hard you try, the scale just won’t budge. What’s going on? Why is your body not cooperating? The answer could be that the “right” eating and activity routine just isn’t right for your biology. Let’s look at blood sugar and weight loss.

When it comes to losing weight, you have to account for your own unique makeup and how your body makes use of the fuel you give it. While that may sound overly complicated, it’s not when you factor in continuous glucose monitors (CGMs). These devices help you look beyond the number on the scale in order to understand your overall well being and how your body’s hormones regulate blood sugar (spoiler alert: big swings and crashes can make it hard to shed pounds). This may come even more into play for women at midlife when a slew of hormonal changes due to menopause can throw off the body’s ability to burn fat (we’ll get more into this below). “Our response to food, exercise, sleep and stress is constantly changing. To add even more complexity, no two people respond the same way to the same food,” says Maziyar Saberi, PhD, systems physiologist and Chief Scientific Officer of January AI. “But we are now in a very fortunate place with CGMs taking the guesswork out of dialing our routines. It’s an extremely powerful tool.”

Bottom line: You’re not imagining things. It really could be that your scale is stubbornly stuck at the same number simply because you have yet to unlock a different way to understand how your body stores fat. That’s where CGMs come in, so let’s dive in.

Blood Sugar And Weight Loss: Why Counting Calories Isn’t Enough

If you’ve ever used a weight loss program, odds are it required you to count calories. Logically, that makes sense: Burn more calories than you consume, and voila! The weight melts right off. Sounds easy, but anyone who has tried to lose weight knows differently. The problem with counting calories is that it oversimplifies the complex process going on in your body. 

While it’s helpful to get an overall sense of how much you’re eating (there’s nothing like seeing what several handfuls of chips really amounts to!), that isn’t enough to ensure you’ll lose weight and keep it off. You have to take into account your own body’s response to food as well as exercise. Other factors matter too, says Saberi. “We cannot neglect the negative effects of chronic stress and poor sleep on weight and overall health. It’s impossible to eliminate stress, but we can dampen its effects by implementing a routine that incorporates regular exercise and relaxation techniques. We can’t do it all at once, it does not happen overnight, and certainly not with fad diets and workout programs. But if we address nutrition, exercise, sleep, stress, and hydration one step at a time, the odds of success increase tremendously.” 

Step one is understanding what’s really going on inside, starting with the big picture of metabolic health.

What Does It Mean to be Metabolically Healthy?

First things first: What is metabolic health? It’s a term used to categorize five main factors that are thought to generally signify overall health: blood sugar (or glucose, read more about what is glucose) levels, blood pressure, triglycerides, cholesterol, and waist circumference. You can learn more about each measure here. When your levels for all five factors fall within a specified range, you’re considered metabolically healthy. When you’re outside of the limits for these categories, you’re at increased risk for metabolic syndrome, which increases the risk of developing type 2 diabetes, heart disease, and stroke. Having just one of the factors, like say, high blood pressure, doesn’t mean you have metabolic syndrome, but the more of these conditions you develop, the greater your risk. Research has shown that when you’re beyond the healthy limits in three or more of the five categories, you’re at significantly greater risk for developing the complete spectrum of disorders. And too many of us are on our way there: According to a 2019 study in the journal Metabolic Health and Related Disorders, only 12 percent of American adults are considered metabolically healthy. 

According to the study, you’d need to meet the following criteria to be considered metabolically healthy:

  • Blood sugar below 100 mg/dL after an overnight fast 
  • Blood pressure below 120/80
  • Triglycerides below 150 mg/dL
  • Waist size less than 40 inches for men and 35 inches for women
  • HDL cholesterol (the “good” kind) greater than or equal to 40 mg/dL for men and 50 mg/dL for women

Where does your weight factor into all of this? Overweight and obesity are factors for developing metabolic syndrome. One 2016 study in the journal JRSM Cardiovascular Disease by British researchers found that simply reducing weight by five to 10 percent could significantly lower all metabolic factors and reduce risk for diabetes and heart disease. So while lots of us have ambitious goals for weight loss, we may be able to accomplish huge gains for our health long before we reach our target number on the scale, or fit into those long-ago favorite jeans. Motivating, right?

How Hormones Affect Weight Loss

In order to understand how metabolic health plays into weight gain and weight loss, you have to grasp the critical role that the hormone insulin plays. When sugar enters our bloodstream after we eat, insulin is needed to move that sugar into our cells where it can be converted into energy. When our bodies don’t require so much that energy (maybe we’re sleeping, sitting at a desk while we work, or, let’s be honest, collapsed on the couch watching Netflix), the excess sugar is first stored in the liver and the muscles as a substance called glycogen. If those stores reach full capacity, glucose finds its next home in our fat cells, as triglycerides.

Between meals and snacks, your insulin levels subside because they aren’t needed to shuttle bursts of blood sugar into cells. But your body still needs a steady source of fuel to power basic functioning (your heart, lungs, brain—every system requires energy) so when it senses low insulin, it taps into glycogen. When glycogen is all used up, your body uses fat stores as a source of energy next. Bingo! You see weight loss. 

Losing weight, however, becomes much harder when your levels of insulin are chronically high, which occurs when there’s too much sugar circulating in the blood. This can lead to insulin resistance, where your cells stop responding normally to insulin. “Think of a lock and key,” says Saberi. “Insulin is the key that opens a lock—called the insulin receptor—in your cells. Once open, the cells allow glucose to enter and convert it to energy. But if the key and lock don’t work well together, the cells never open and the glucose stays in the bloodstream. That is what we call insulin resistance.” In response, your body produces more and more insulin to push the cells to unlock and absorb circulating sugar, which only makes matters worse. Insulin levels stay high, the body never gets a signal to run through glycogen and then burn fat stores for energy, so weight loss becomes challenging, if not impossible.

In other words, if we don’t get our insulin levels in check, our bodies are chronically in fat-storage mode instead of fat-burning mode. The key to getting back on track and losing weight: Make sure our blood sugar levels are stable and our insulin production never goes into overdrive. 

A continuous glucose monitor (GGM) can give you vital insight into this process. Because it constantly tracks your glucose levels throughout the day and night, it gives a detailed picture of the impact of the foods you eat, and when you eat them, on your blood sugar levels. Certain foods at certain times will cause blood sugar to spike, and your body will produce insulin in response. Avoid those foods and you help to control insulin production, which gives your body a fat-burning advantage. 

A CGM will also show you the impact of activity, and why it matters. “Identifying multiple approaches to lower glucose without the need for insulin is critical,” says Saberi, “and this is where exercise comes into play. Muscle contraction during exercise helps the body use glucose without the need for insulin. We call it insulin-independent glucose disposal. This is why exercise is so important for managing blood glucose levels.” Put it all together—activity, healthy food choices and watching overall calories—and you ensure your body will be working with, not against you, on a weight loss journey. 

Women & Midlife Weight Gain

As women enter menopause around age 50, maintaining a consistent weight may suddenly become an uphill battle. Even if you keep up with the same exercise and eating habits, it’s not uncommon to start gaining. 

So what’s going on? During the transition from perimenopause to menopause, your body’s hormones go through a series of changes that cause your metabolism to slow, thanks to a declining estrogen level that drags down muscle mass with it. As a result, your body needs to burn fewer calories to keep you alive and active—and more of that excess glucose is going to get stored as fat. So while your doctor may simply say, “eat less,” as the answer to your midlife weight gain, the real trick is eating smarter. When you focus on foods that keep blood sugar levels lower and more stable, you decrease your insulin spikes and risk of developing insulin resistance. 

This makes monitoring blood sugar levels incredibly smart for women at midlife. As your body’s response to food changes, you can track what’s going on by monitoring your glucose levels at every meal. Modifying your diet to align with your new reality is easier when you’re able to pick foods that actually work well with your body’s need to burn fat, instead of working against it. 


How to use CGM for weight loss?

A continuous glucose monitor (CGM) is a wearable device that, as the name implies, continuously tracks your glucose levels around the clock. Through a quick, painless insertion process (you’ll feel a tiny pinch), the CGM affixes to your skin so it can track and test your blood sugar in nearly real-time. ( uses the Abbott FreeStyle Libre, which you can learn more about here.) Once you have the CGM in place you can put it to work for your weight loss goals by seeing how different foods impact your blood sugar levels at different times of day. This will allow you to tweak your diet in ways that help your blood sugar remain stable, which in turn can help trigger your body to burn stored fat. 

Does lowering blood sugar help increase weight loss?

When blood sugar (or glucose) is high, your pancreas is triggered to produce more insulin to move that sugar out of your blood and into your cells. That’s a problem for weight loss, because your body only burns fat when it senses insulin levels dropping. Supplied with too much sugar and too much insulin, your body stores that sugar as fat that never gets burned. So while you might think you’re humming along just fine, your body may be in a chronic state of insulin production because of your chronically high blood sugar levels. This makes weight loss really hard to achieve. 

Stable blood sugar, on the other hand, means your cells don’t get flooded with insulin, which in turn gives your body time to burn fat for energy in between meals. The result: weight loss. If you want to use a CGM to drop pounds, take a look at how your blood sugar levels respond to different foods. Seeing your levels swing wildly after a meal? What you ate may undermine your weight loss efforts. See other foods that keep blood sugar relatively stable? Those are much more likely to help you lose. 

What should my glucose levels be for weight loss?

These are the benchmarks you can strive for when tracking with your CGM to make sure things are at least within a healthy range when you wake up in the morning (this gives you a “fasting” reading).

  • Normal: Below 100 mg/dl
  • Prediabetes: 100 to 125 mg/dl
  • Diabetes: 126 mg/dl or more

That said, consult with a healthcare professional about where you want your numbers to be in order to reach your goals for optimal weight loss and overall health. Your target numbers are going to depend on metabolic factors that are personal to you.

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