• Dec 2023

Guide: What are normal glucose (blood sugar) levels?

Guide: What are normal glucose (blood sugar) levels?
  • Your glucose levels, also known as your blood sugar levels, have a major impact on your health and well-being, including your long-term metabolic health. 
  • Although every person is different, there are glucose ranges that are considered “normal” or “typical” for healthy adults, and values outside of these ranges may signal metabolic dysfunction.  
  • Continuous glucose monitors (CGMs) like Lingo can help you track your glucose levels and learn how to optimise your nutrition and habits to improve your overall metabolic health.  

Your glucose levels (also known as blood sugar levels) play an important role in your overall health and well-being, impacting your energy levels, sleep patterns, hunger and cravings, and more.

For example, if you’ve ever felt low energy or sudden hunger or cravings after a big meal, it’s likely related to your glucose patterns; the crash that often follows a meal directly influences hunger and appetite and the flux in glucose impacts energy. Maintaining steady glucose levels can have an impact on your health today and influence future health risk. (1)

Although every person is different, there are standard glucose levels established for healthy individuals without diabetes. These are sometimes referred to as “normal” or typical, and values outside of this range can be concerning. Consistently low values, known as hypoglycemia, bring about unpleasant symptoms and consistently high levels may fall into the pre-diabetes or diabetes range. 

Knowing your glucose levels and monitoring how your body processes glucose can give you a window into your overall metabolic health and well-being and help prevent more serious chronic conditions. 

Here, we break down what you need to know about glucose, why your levels matter, how to track your glucose, and what is considered a “normal” or typical range. 

What is glucose and do your glucose levels matter?

Glucose is one of your body’s main sources of energy. It’s essential for healthy cell function, and it’s the main source of fuel for your brain. Glucose comes from the food we eat; more specifically, carbohydrates are converted into glucose, which then circulates through the bloodstream to be used immediately for energy or stored for later. 

As glucose moves through your bloodstream, your pancreas releases the hormone insulin to help utilise the glucose for energy. Any glucose that's not used as an immediate source of energy is shuttled to the liver, muscles, or fat cells and stored for later use.

Glucose is necessary, but it is possible to have too much of it, especially if your body can’t use insulin properly. If glucose levels are chronically high, this is known as hyperglycemia, or commonly referred to as high blood sugar. This persistent hyperglycemia can lead to developing pre-diabetes or type 2 diabetes.

In addition to concerns associated with high glucose, continual glucose spikes and crashes can leave you with feelings of low energy, low focus, constant cravings, unsteady moods and poor-quality sleep. In the long term, this glucose roller coaster can lead to health complications, with research suggesting an increased risk for developing insulin resistance, type 2 diabetes, and cardiovascular issues. (1)

Glucose levels are primarily impacted by the food you eat, especially if you eat a high-carb diet and a lot of sugar. Refined carbohydrates, such as white bread, pasta, pastries, and white flour, have been stripped of their bran, fibre, and nutrients. These choices typically cause a glucose spike that’s more significant than non-refined and complex carbohydrates.

Complex carbs include peas, beans, whole grains, and vegetables and aren't as likely to spike your glucose as simple carbs. Fruit is naturally high in fructose, a simple sugar, and can be the culprit behind a spike, but most fruits contain healthy fibre and other beneficial nutrients. With a bit of planning, you can enjoy fruit and stay steady.

It’s not just what you eat that can impact your glucose levels, but also how you eat. Eating “naked carbs” — that is, carbs by themselves — can cause more of a glucose spike than eating carbs paired with a source of protein and/or fat. So, instead of a slice of toast and jam, opt for toast with smoked salmon and avocado. Another way to lessen a spike is to eat your carbs after you enjoy the vegetables, fat, and protein on your plate; eat the chicken and broccoli before moving onto the risotto.

Glucose levels are also impacted by lifestyle factors such as stress, quality of sleep, and exercise. High-intensity exercise in particular can cause a glucose spike because it increases adrenaline (the fight-or-flight hormone), which signals to your body that it’s time to break down stored liver glycogen into glucose. This quick influx of fuel can spike your glucose, but in this case, a spike is a good thing.

Tracking glucose levels

Even if you're otherwise healthy, it’s important to know your glucose levels. Consistent ups and downs or persistent hyperglycemia could signal a risk for a bigger metabolic condition down the road.  

Thanks to advancements in technology, there are now several ways you can track your glucose levels at home. One of the easiest and least invasive ways is through continuous glucose monitors (CGMs), which track your glucose in real time. The Lingo biosensor, like most CGMs, use interstitial fluid rather than blood. The device includes a tiny filament the size of an eyelash, adheres to your arm, and is worn for up to 14 days before it’s swapped out for another one.

The advantage of using a CGM like Lingo is that it connects to your smartphone, allowing you to track your glucose in real time.  You’ll see the continuous data and gather insights, which allows you to assess how your habits impact your health.  Lingo also offers real time coaching to guide you as you make choices and build new habits to help retrain your metabolism.

Normal glucose levels

Glucose trends are unique, and even the same individual can have a glucose pattern that varies from day to day due to a variety of factors such as diet, exercise, sleep, and stress.

There is a glucose range that is considered "normal” or typical for metabolically healthy people. This range is 70-140 mg/dL (milligrams per decilitre) or 3.9-7.8 mmol/L (millimoles per litre). You may notice levels at the lower end of this range while fasting (meaning not having eaten anything in the last few hours), and up to 140mg/dL (7.8mmol/L) after eating. Those without metabolic dysfunction stay within this range most of the time. While sharp upticks above the average glucose value indicate a spike, most healthy individuals still stay around the 140mg/dL (7.8mmol/L) level even during a spike and return down to normal levels within a few hours.

In individuals with pre-diabetes and diabetes, typical glucose ranges from 70-180 mg/dL (3.9-10.0mmol/L) with lower levels often seen while fasting, and up to 180mg/dL (10.0mmol/L) after eating. A lab value draw resulting in fasting glucose level of 126 mg/dL (7.0mmol) or higher may indicate diabetes, and people with diabetes will often have a spike over 200 mg/dL (11.1mmol/L) after they eat.

It’s important to note that just because you see a spike over 200mg/dL (11.1mmol/L) doesn’t necessarily mean you have diabetes or are metabolically unhealthy, especially if your glucose returns down to more “normal” levels. If you have questions about your glucose values, be sure to check in with your health care team.  

As we learn more about glucose levels and spikes with CGM data, it’s becoming apparent that spikes happen more often than was previously understood. Even in generally healthy individuals, these glucose spikes can play a big role in your general well-being.

Alternatively, there is such a thing as having glucose levels that are too low, also known as hypoglycemia. This is rare but occurs when your fasting glucose is less than 70 mg/dL (3.9mmol/L). Symptoms of hypoglycemia include hunger or nausea, fatigue, confusion and/or inability to focus, irritability or anxiety, dizziness, shakiness, or lightheadedness.

If you wear a CGM like Lingo, your goal should be to stay within the 70-140mg/dL (3.9-7.8mmol/L) range and minimise the number of spikes and severity of spikes that occur. With Lingo, we take your glucose data and convert it to a simple target called a Lingo Count. Your Lingo Count and accompanying glucose graph indicate when you are spiking so you can better understand your individual response to food and other lifestyle factors. Lingo can help you create habits that will keep your glucose steady and benefit your overall well-being. 

A final note from Lingo

Having insight into your glucose levels can help you understand your metabolic health and unique responses to food. What you eat and how your body breaks it down can impact your sleep, energy levels, focus, hunger, cravings, and more. Maintaining glucose within the “normal” range is also crucial for long-term health; higher blood sugar levels can indicate a bigger metabolic condition and lead to chronic issues such as insulin resistance, pre-diabetes, diabetes, or heart disease. (2)

Tracking your glucose with a CGM gives you a window into your metabolic health with real-time data and can help you optimise your nutrition and lifestyle choices. With Lingo, you’ll get personalised coaching to help you create healthy habits and make the best choices to reduce spikes and improve your overall well-being.


  1. Wyatt P, et al. Postprandial glycaemic dips predict appetite and energy intake in healthy individuals. Nat Metab. 2021 Apr;3(4):523-529. Hyperlink: Postprandial glycaemic dips predict appetite and energy intake in healthy individuals - PubMed (nih.gov)
  2. ElSayed NA, et al, on behalf of the American Diabetes Association. 2. Classification and Diagnosis of Diabetes: Standards of Care in Diabetes-2023. Diabetes Care. 2023 Jan 1;46(Suppl 1):S19-S40.

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