Glucose (blood sugar) affects your metabolic health. Though fluctuations are normal, high levels and large fluctuations of blood glucose throughout the day can lead to insulin resistance, weight gain, and Type 2 diabetes. Keeping blood sugar within normal levels (80-120 mg/dL) and reducing drastic changes in blood glucose levels are key to staying metabolically healthy.
A continuous glucose monitor (CGM) lets you track your blood sugar levels in real-time. When you discover what is driving high glucose variability, you can make informed diet and lifestyle changes to improve your metabolic health, which will make it easier to lose weight.
The relationship between blood sugar and weight loss
When you eat, your body breaks down carbohydrates into glucose, the body’s preferred energy source. The pancreas produces insulin in response to increased blood sugar levels, acting like a “key” that unlocks cells. Cells can then take in and use the glucose from your blood.
If your diet contains too many processed, refined carbohydrates (e.g., white flour) or added sugar — more than you need for energy — and you have elevated blood sugar levels, you produce more insulin than necessary [1].
Over time, these spikes in insulin can cause your cells to become less sensitive to insulin’s action. This forces your pancreas to produce even more insulin to keep your cells taking in sugar – which is known as insulin resistance.
The extra insulin circulating in your body then tells your liver to convert excess sugar into fat instead of using it for energy. This fat is stored in the liver, adipose (i.e., fat tissue), and various parts of the body. While adipose is made to store fat, excess adipose tissue equals excess weight and can lead to abnormal hormone levels [2].
With or without excess weight, too much fat in the liver can pose health issues, such as an increased risk for heart disease and Type 2 diabetes [3]. Throughout the body, large amounts of stored fat can increase cellular damage [4].
When blood sugar levels are high, your body will release stress hormones, such as cortisol, which trigger cravings for more high-sugar foods like bread made with white flour, potatoes, and sweets that contain high-fructose corn syrup and refined sugar [5]. Less-processed carbs (known as complex carbs, which are usually whole, unprocessed plant foods that contain their natural fiber content) are associated with better weight loss outcomes and a more effective dietary strategy.
This is a vicious cycle of cravings, insulin resistance, decreased hormone regulation, and declining metabolic health that makes it difficult to lose weight.
Optimal blood sugar levels for weight loss
Fluctuations in blood sugar are a normal physiologic response, but continued variability and sustained high blood glucose levels after eating become problematic [6]. Even in healthy individuals, high variability in fasting blood glucose levels is associated with negative health outcomes [7].
Normal fasting blood sugar levels are between 80 and 100 mg/dL [8]. Blood sugar levels below 70 mg/dL are considered low (hypoglycemic), and levels above 140 mg/dL after a meal are considered high (hyperglycemic) [9].
Although there are no clinically established numbers that guarantee weight loss, it's critical to keep your glucose levels within a healthy range and minimize drastic variations. This will decrease cravings, improve hormone balance, and increase insulin sensitivity — all of which are associated with a healthy weight.
Monitoring blood glucose gives a picture of where you currently are. It lets you track changes over time, allowing you to understand what habits will improve your metabolic health, balance your hormones, and make weight loss possible.
One important aspect to consider — especially if you follow a keto diet — is being mindful of balance in fat, protein, and carbs [10]. Low glucose peaks, low variation, and not letting your high blood sugar get too high are easier to accomplish with a low-carb diet. However, regularly eating high-calorie foods, whether fat or carbohydrate-dominant, can hinder weight loss or even drive weight gain.
It’s best to take a holistic approach by also considering your intake of micronutrients and fiber through fruits and vegetables, which also contribute to metabolic health and, therefore, a healthier weight.
Glucose monitoring provides you with a compass, leading you in the right direction, but there is rarely one direct path. Combining information on your glucose levels with healthy food and lifestyle habits will guide you toward your goals.
How measuring glucose can help you lose weight
We believe the best source of truth is your own body. Measuring glucose can be used as part of an overall strategy to lose weight by giving you concrete numbers on your metabolic health in a way that’s impossible with a scale or a mirror.
By understanding where you are and what foods and habits are keeping your glucose levels stable, you can improve your metabolic health and, ultimately, lose weight.
There is plenty of generic diet advice about things like wheat bread vs. sourdough and potatoes vs. pasta, but each of us has a unique response to food based on everything from genetics to microbiome. Experimenting to see which meals are driving the biggest glucose responses helps you figure out which foods to keep and which foods to kick.
You might be surprised by foods that you thought were good for you, or that were marketed as healthy, which are actually causing dramatic blood sugar spikes.
In addition to food, glucose monitors, when paired with an app like Veri, can be used to track how different habits like exercise, sleep, and meal timing, impact your blood sugar.
Regular exercise helps to make cells more receptive to insulin, which helps to regulate blood sugar levels. Different types of exercise have varying impacts on metabolic health, so tracking changes lets you explore what workouts are most beneficial for your blood sugar.
CGMs paired with exercise timing also allow you to see what time of day is best to work out for better glucose levels, or if a post-meal walk can help mitigate the spike of a higher-carb meal. You can also use CGMs to assess how the amount of sleep or having a consistent bedtime affects your glucose levels over the following day.
What if I don’t have a CGM?
If you don’t have a CGM, it’s a good idea to start by reducing foods that have a high glycemic index, as these spike blood glucose levels [8]. It’s also vital to make sure you’re eating the right kinds of carbs. Complex carbohydrates contain fiber, which slows down digestion and prevents blood sugar levels from spiking too quickly [11]. If you do try a CGM, it can teach you which high-fiber foods best suit your metabolic needs and can also help with weight loss.
Key Takeaways
Continuous glucose monitors track personal data on blood sugar levels and can help to eliminate guesswork when making diet choices to improve your metabolic health, which will reverse the factors that can make weight loss so hard.
- Frequent high glucose levels can lead to insulin resistance and hormone imbalance, a predictor of excess weight gain.
- Keeping your blood sugar near a normal range and minimizing variation in blood sugar levels are critical to metabolic health, but many people only focus on the former. High variation is associated with worse health outcomes.
- Glucose monitoring shows your unique glucose response to specific foods and habits so you can be empowered to make informed decisions for your health.
CGMs are a tool that can help you better manage your weight loss efforts – they’re not magic solutions, but they do provide valuable insights into what diet and lifestyle changes might be affecting your blood sugar levels.
Sarah Jayawardene is a nutrition and health writer who focuses on metabolism and metabolic diseases. She obtained a Bachelor’s degree in Biochemistry from Loyola Marymount University and a Master’s degree in Biochemical and Molecular Nutrition from Tufts University. Sarah is an avid baker – she has a sweet tooth and is always on the look for healthier versions of her favorite desserts.
References:
- https://www.heart.org/en/healthy-living/healthy-eating/eat-smart/sugar/how-too-much-added-sugar-affects-your-health-infographic
- https://academic.oup.com/ptj/article/88/11/1265/2858148
- https://www.tandfonline.com/doi/full/10.1080/07853890510037383
- https://academic.oup.com/ptj/article/88/11/1265/2858148
- https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9362746/
- https://journals.plos.org/plosbiology/article?id=10.1371/journal.pbio.2005143
- https://cardiab.biomedcentral.com/articles/10.1186/s12933-022-01448-1
- https://www.cdc.gov/diabetes/managing/manage-blood-sugar.html
- https://www.who.int/data/gho/indicator-metadata-registry/imr-details/2380
- https://www.cambridge.org/core/journals/british-journal-of-nutrition/article/ketogenic-diets-physical-activity-and-body-composition-a-review/2872800CAE5F54E368EBF8E0A6F1214E
- https://www.hsph.harvard.edu/nutritionsource/carbohydrates/carbohydrates-and-blood-sugar/
