Normal Blood Glucose Levels: For People With & Without Diabetes

Wondering what your blood glucose levels should be? Well - that’s a difficult question to answer. It depends on so many factors, including whether you have diabetes or not, the type of diabetes you have, and biological influences. However, if you don’t have diabetes, it’s useful to be aware of normal blood sugar levels for a non-diabetic person, especially normal blood sugar levels after eating, as high blood sugar levels can be a sign of diabetes. If you have diabetes, your target blood glucose levels will be different to someone without diabetes. So we’ll also cover the ideal blood sugar ranges for people with Type 1 diabetes, Type 2 diabetes and gestational diabetes.

Blood Sugar Metrics

Your blood glucose levels will naturally go through highs and lows throughout the day - these variations depend a lot on when and what you eat, but there’s a bunch of other factors that affect blood sugar levels. More on that in a bit.

Here’s what you need to know right now: checking your blood sugar isn’t as simple as checking your weight, although it’s equally as helpful in understanding your health. Because your blood glucose changes a lot, one measurement might not reveal the full picture.

Here are the most popular blood sugar metrics, all useful for understanding your blood glucose levels:

  • Fasting Glucose: Fasting Blood Glucose (FBG) is your glucose level after fasting for 8 hours. In order to be classified as “normal”, and not pre-diabetic or diabetic, your FBG should be below 100 mg/dl.
  • Pre-Meal (Baseline Glucose): This is your blood sugar reading before a meal. It will likely be one of the lowest readings during a day.
  • Post-Meal Glucose Peak: This is the glucose spike you’ll experience 45 minutes to 1 hour after your meal.
  • Mean 24-Hour Glucose: This is your average glucose level over a day.
  • A1C: A1C used to be the standard blood glucose metric for people with diabetes. It gives you an average blood glucose reading, expressed as a percentage, over 2-3 months.
  • Time-in-Range: Now considered the gold standard, Time-in-Range indicates the percentage of time an individual is within a target range.

Finger prick to measure Blood Sugar
Finger prick to measure Blood Sugar

What Affects Blood Glucose Levels?

Before we get into normal blood sugar levels for people without diabetes, and for people with diabetes, let’s explore the factors that affect blood glucose levels:

  • Diabetes: Diabetes affects your body’s ability to produce insulin, use insulin, or both. Since insulin is critical in regulating blood sugar levels, whether you have diabetes or not, and the type of diabetes you have, affects your blood sugar levels.
  • What you eat: One of the most significant factors is what you eat and has a huge influence on your blood glucose levels. In particular, the more carbs you eat, the more likely you will have a post-meal blood glucose spike. You can lower the impact of carbs by consuming fibre at the same time.
  • When you eat: Meal timing also has an effect on blood sugar levels. Beside from the fact your blood glucose will spike just after you eat and dip before your next meal, the effect of meal timing on blood sugar levels varies a lot from person to person. For example, some people find that a late-night meal results in high glucose levels overnight.
  • Medication: Medication can affect different people’s glucose levels in different ways. When you have diabetes, it’s helpful to compare your blood sugar before and after taking medication to understand its full effects.
  • Exercise: The intensity of your exercise, and when you do it, can both increase and decrease your blood glucose. Light exercise is often recommended to lower overall blood sugar levels, but exercise that’s too high intensity can actually increase blood glucose. That’s because your body needs extra energy during high intensity exercise, so levels of certain hormones, like adrenaline, rise, boosting the glucose your body is retrieving from storage. Even though your glucose utilisation has increased, your blood glucose levels have increased more, leaving you with a temporary post-exercise blood sugar spike.
  • Sleep: Not getting enough sleep can increase your blood glucose levels.

This is not even nearly an exhaustive list - you can find a fuller list of factors that affect blood glucose here - but these are some of the most common reasons for blood glucose fluctuations. There are plenty of biological factors that affect blood sugar as well, like puberty, menstruation, and having Celiac disease.

It’s also easy to overlook behavioural and decision-making factors that have a way bigger effect on our blood glucose levels than we actually think. In reality, the number of times you check your blood glucose, your decision-making biases and social pressures influences your attitude towards controlling your blood sugar levels, so often has a significant effect.

This really illustrates the strength of Time-in-Range, which is considered the gold standard in blood glucose monitoring. Instead of focusing on an average, like A1C, or one measurement, like fasting glucose, Time-in-Range accounts for all the variations in your blood sugar levels, giving you a percentage of time you are within your target glucose range.

See more about our Time-in-Range in this blog post.

Normal Blood Sugar Levels For People Without Diabetes

Non-diabetic individuals should aim for blood glucose metrics in the following ranges:

  • Fasting Glucose: 80-86 mg/dl
  • Pre-Meal (Baseline Glucose): 72-90 mg/dl
  • Post-Meal Glucose Peak: 99.2 ± 10.5 to 137.2 ± 21.1 mg/dl
  • Mean 24-Hour Glucose: 89-104 mg/dl
  • A1C: 4-5.6%
  • Time-in-Range: 90% of the day within 70-120 mg/dl

Every study into normal blood sugar levels for adults finds slightly different results, because every sample population is different. And metrics like the post-meal glucose peak, which indicates normal blood sugar levels after eating, can vary hugely depending on what you eat. But the ranges we give above take into account the conclusions of the most recent, reputable studies, like this study on continuous glucose monitoring in healthy individuals.

Blood Glucose Response for Diabetes
Blood Glucose Response for Pre-Diabetics, Diabetics and Non-Diabetics

Ideal Blood Sugar Levels for People with Diabetes

If you have any type of diabetes, it’s important to speak to your doctor to understand your target blood glucose readings. As we’ve discussed, blood sugar depends on so many factors, and for people with diabetes, there are real dangers of not getting your targets right. So speak to your healthcare practitioner to learn about your ideal blood glucose goals.

However, from the wealth of scientific research, here are some general guidelines into blood glucose goals for people with diabetes.¹𝄒²

Type 1 Diabetics Type 2 Diabetics Gestational Diabetes Children with Type 1 Diabetes
Pre-Meal (Baseline Glucose) 80 to 130 mg/dl 80 to 130 mg/dl 80 to 130 mg/dl 80 to 130 mg/dl
Post-Meal Glucose (>90min) 90 to 160 mg/dl Less than 180 mg/dl 120 to 140 mg/dl 90 to 160 mg/dl
A1C Up to 6.5% Less than 7% Up to 6.5% Up to 6.5%

[1] https://www.guidelines.co.uk/diabetes/nice-type-1-diabetes-guideline/252655.article
[2] https://www.webmd.com/diabetes/guide/normal-blood-sugar-levels-chart-adults

How to Control Your Blood Sugar

Whether you have diabetes or not, the important thing to remember is that everyone’s blood glucose levels are naturally different. You could eat, sleep and exercise exactly the same as someone else, and your readings could still be dramatically different to each other.

CGM Reader and Sensor
CGM Reader and Sensor

That’s why Continuous Glucose Monitoring (CGM) devices are so powerful. With traditional Blood Glucose Monitoring (BGM), you need to use a fingerstick, and measuring your blood sugar is a manual process. CGMs provide a new level of freedom - it’s a sensor inserted just under your skin, connected to a transmitter. CGMs automatically take blood glucose readings at regular intervals (without you even noticing), allowing you to get more data on your blood sugar variations throughout the day compared to traditional BGM.

Analysis Screen of the SNAQ App with a Glucose Chart
Glucose Chart in Analysis Screen in the SNAQ App

Sync your CGM with SNAQ, which allows you to see how your meals affect your glucose levels. You can see your glucose curve for each meal, and make more intelligent choices about the food you eat, with a better understanding of how they will affect your blood sugar.


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