Weight Loss Tip: A Guide to Blood Glucose & Blood Glucose Monitoring for Weight Loss

Many of us have tried to lose weight without understanding the role of blood glucose. By the way, blood glucose is simply the medical term for blood sugar. You’ll have heard of blood sugar, you’ll know it’s important, you’ll likely have felt it dip at times, but you may not understand exactly what's going on or why understanding it better could help you lose weight.

People who suffer from diabetes understand blood sugar however, and need to monitor their blood sugar throughout the day. For the rest of us, understanding how blood glucose and blood glucose monitoring can support your weight loss journey can be a game-changer.

What is blood glucose?

Blood glucose, also known as blood sugar, is the sugar in your bloodstream that your body uses for energy. When you eat, your digestive system breaks down carbohydrates (that you might find in bread, pasta, rice, fruit and vegetables) into glucose, which enters your blood. Your body then releases insulin to help the cells absorb and use this glucose for energy.

Your “blood glucose”, also known as “blood sugar”, refers to the concentration of glucose present in your bloodstream. Glucose is a primary source of energy for your body's cells, and it plays a crucial role in maintaining your overall health.

How does blood glucose work?

Digestion and Absorption: When you eat carbohydrates (e.g., bread, rice, pasta, fruits, and vegetables), your digestive system breaks them down into glucose. This glucose is absorbed into your bloodstream, causing your blood sugar levels to rise.

Insulin Release: In response to the rise in blood glucose, your pancreas releases the hormone insulin. Insulin acts as a key to allow glucose to enter your cells, where it can be used for energy.

Cellular Uptake and Energy Production: Glucose is ‘taken up’ by cells, primarily muscle and fat cells, and used for energy production. Some glucose is stored in the liver and muscles as glycogen for later use.

Blood Glucose Regulation: When blood glucose levels are too high, the pancreas releases more insulin to lower them. If blood glucose levels drop too low, the pancreas releases glucagon, which prompts the liver to convert glycogen back into glucose, raising blood sugar levels.

Your body is able to finely tune your blood sugar using insulin, so that you can get the energy you need from the food you eat and process it optimally.

What are healthy blood glucose levels?

Normal blood glucose levels are typically measured in milligrams per deciliter (mg/dL) or millimoles per liter (mmol/L). The recommended fasting blood glucose levels, (that’s the level you have before eating) are generally:

For non-diabetic adults: 70-100 mg/dL (3.9-5.6 mmol/L)Fr individuals with diabetes: Target levels can vary, but generally fall within the range of 80-130 mg/dL (4.4-7.2 mmol/L) before meals and below 180 mg/dL (10 mmol/L) two hours after meals.

What happens to your blood glucose if you're diabetic?

When someone has diabetes, their blood glucose (blood sugar) levels can become abnormally high. The effects depend on what type of diabetes a person has; type 1 diabetes or type 2 diabetes, as well as individual factors like diet, physical activity, and medication use.

What typically happens to your blood glucose levels if you have type 1 diabetes?

In type 1 diabetes, the immune system mistakenly attacks and destroys the insulin-producing cells (beta cells) in the pancreas. The following can occur:

Insulin Deficiency: The body produces little to no insulin, a hormone that helps glucose enter cells for energy. This leads to a severe insulin deficiency.

High Blood Glucose: Without sufficient insulin, glucose cannot enter cells, so it accumulates in the bloodstream, resulting in high blood sugar levels.

Hyperglycemia: Persistently elevated blood sugar levels, known as hyperglycemia, can cause symptoms like frequent urination, excessive thirst, unexplained weight loss, fatigue, and blurry vision.

Ketoacidosis Risk: In the absence of insulin, the body may break down fat for energy, leading to the production of ketones, which can result in diabetic ketoacidosis which is a potentially life-threatening condition.

What typically happens to your blood glucose levels if you have type 2 diabetes?

In type 2 diabetes a person will experience insulin resistance, where the body's cells don't respond effectively to insulin, and over time, the pancreas may produce less insulin. The following can occur:

Insulin Resistance: Cells don't respond well to insulin, so they don't take up glucose effectively, causing elevated blood sugar levels.

Beta Cell Dysfunction: Over time, the pancreas may struggle to produce enough insulin to compensate for insulin resistance.

Hyperglycemia: As with type 1 diabetes, untreated type 2 diabetes leads to elevated blood sugar levels and the potential for complications if not managed.

Type 2 diabetes typically develops gradually, and symptoms may not be as pronounced as in type 1 diabetes. Some people with type 2 diabetes may not experience noticeable symptoms at first.

Both types of diabetes can result in long-term complications if blood glucose levels are not adequately controlled. These complications can affect various organs and systems in the body, including the eyes, kidneys, nerves, heart, and blood vessels. Individuals with diabetes need to manage their condition through lifestyle modifications, medication, insulin therapy (if deemed necessary), regular monitoring of blood glucose levels, and healthcare provider guidance to prevent complications and maintain good overall health.

As such, people with diabetes often regularly monitor their blood glucose levels, and are often very aware of their blood sugar levels and the impact of various foods and activities on their blood glucose.

How did people traditionally measure blood glucose?

Before the advent of Continuous Glucose Monitors (CGMs) - (we’ll come onto those!), blood sugar was measured using several methods, primarily through ‘point-in-time’ measurements including:

Blood Glucose Meters: Blood glucose meters are portable devices used to measure blood sugar levels. They require a small sample of blood, typically obtained by pricking a finger with a lancet, which is then applied to a test strip. The meter reads the glucose concentration in the blood and provides a specific value in milligrams per decilitrer (mg/dL) or millimoles per litre (mmol/L). These machines are relatively cheap (around £20/$25) and can be used at home (or out and about) by anyone. The finger prick doesn't exactly hurt, by the way but it can be annoying. Users typically measure their blood sugar levels multiple times a day, especially before and after meals, and at other relevant times. Users. may also have some sort of tracker app, or a simple note book to keep track of their measurements.

Laboratory Blood Tests: Blood samples are taken (like a standard blood test) and sent to a lab for analysis. Laboratory tests can provide more accurate and comprehensive results, often including measurements of fasting blood glucose levels, haemoglobin A1c (HbA1c), and other relevant markers. These tests are typically ordered by healthcare providers for diagnostic purposes and for assessing long-term glycemic control.

Urine Glucose Testing: Historically, urine testing was used to estimate blood glucose levels. Individuals would collect a urine sample, and test strips were dipped into the sample to assess the presence of glucose. However, this method is less precise than blood glucose meters and can only provide a rough estimate of blood sugar levels. It has largely been replaced by more accurate methods.

Oral Glucose Tolerance Test (OGTT): This test involves fasting overnight and then drinking a solution containing a specific amount of glucose. Blood samples are taken at intervals after drinking the solution to assess how the body processes glucose. It is used for diagnosing conditions like gestational diabetes and impaired glucose tolerance.

Fasting Blood Glucose Test: This is a simple blood test to measure blood sugar levels after an overnight fast. It's typically used for diagnosing diabetes or pre-diabetes.

Haemoglobin A1c (HbA1c) Test: The HbA1c test provides an estimate of an individual's average blood sugar levels over the past two to three months. It's a useful marker for assessing long-term glycemic control.

While these traditional methods of blood glucose measurement are still widely used today, there’s a new way to measure blood sugar that is way less messy and time-consuming and it’s known as the Continuous Glucose Monitor or CGM. CGMs have added a new dimension to diabetes management by providing continuous, real-time data about blood sugar levels.

What is a Continuous Glucose Monitor (CGM)?

A Continuous Glucose Monitor (CGM) is a medical device used to continuously and automatically measure and monitor blood glucose levels in real-time. CGMs are particularly valuable for individuals with diabetes, as they provide detailed and continuous information about blood sugar fluctuations, helping with better diabetes management.

A CGM is usually worn on the arm, and connects to a device or app that allows the user to monitor and interpret the data in real-time. With a CGM you can know your blood sugar levels at any one time, and learn how it changes over time.

How do CGMs work?

Continuous Glucose Monitors are more than just the sensor itself. They comprise several parts:

Sensor: CGMs consist of a small sensor that is inserted just under the skin, usually on the abdomen or arm. This sensor measures glucose levels in the interstitial fluid, which is the fluid that surrounds the body's cells. You may have seen some people with a patch on their arm; that could well be a CGM.

Continuous Monitoring: The CGM sensor continuously measures glucose levels, typically at intervals ranging from every 1 to 5 minutes, depending on the device. This data is then sent to a small transmitter or a smartphone app.

Transmitter and Receiver: The transmitter wirelessly sends the glucose data to a receiver or a smartphone app, where it is displayed in real-time. Some CGMs have standalone receivers, while others can connect directly to smartphones or insulin pumps.

Data Analysis: The CGM system uses algorithms to analyse the glucose data, providing information on current glucose levels, trends (whether glucose is rising, falling, or stable), and predictions about where glucose levels are headed.

Alerts and Alarms: CGMs can be programmed to send alerts or alarms when blood glucose levels go outside of preset target ranges. This helps individuals with diabetes take prompt action to prevent hypoglycaemia (low blood sugar) or hyperglycaemia (high blood sugar).

Why are CGMs great for diabetes treatment?

Continuous Glucose Monitors have revolutionised diabetes management, as they empower individuals with diabetes and their healthcare providers to make more informed decisions about insulin therapy, lifestyle adjustments, and meal planning. They can lead to better glycemic control, reducing the risk of both hyperglycaemia and hypoglycaemia and improving overall quality of life for people with diabetes.

How does blood glucose change throughout the day?

People who monitor their blood sugar will know that blood sugar changes over the course of the day. Some of the factors that can cause blood glucose to change include:

Food: After eating, blood glucose levels rise as carbohydrates are digested and absorbed. The type of carbohydrates you consume can impact the rate at which your blood sugar rises. Simple carbohydrates, like those found in sugary foods and refined grains, are rapidly digested and can cause a quicker and more substantial blood sugar spike than complex carbohydrates found in whole grains, and vegetables.

Portion Size: The quantity of carbohydrates you consume also plays a significant role. Larger portion sizes, especially of high-carb foods, can lead to more significant blood sugar spikes.

Glycemic Index (GI): The glycemic index is a measure of how quickly a carbohydrate-containing food raises blood sugar levels. Foods with a high GI cause a rapid spike, while those with a low GI result in a slower, more gradual increase.

Fibre: Fibre in food can slow down the absorption of glucose and help stabilise blood sugar levels. A meal or snack low in fibre may lead to faster and more significant spikes.

Fasting: Overnight and between meals, your liver releases glucose from glycogen stores to maintain blood glucose levels, preventing them from dropping too low. Skipping meals or going for extended periods without eating can cause blood sugar levels to drop, and when you eventually eat, your body may release more glucose, leading to a spike.

Exercise: Physical activity can lead to a decrease in blood glucose levels, especially during and immediately after exercise. This is because exercise promotes the uptake of glucose into muscle cells, reducing its concentration in the bloodstream. Strenuous exercise can lead to temporary blood sugar spikes as the body releases glucose for energy during activity.

Stress and Hormones: Stress and certain hormones, like cortisol, can raise blood sugar levels. The "fight or flight" response triggers the liver to release glucose into the bloodstream for quick energy in response to stress.

Illness or Infection: Infections or illnesses can trigger the release of stress hormones, leading to elevated blood sugar levels. It's common for people with diabetes to experience increased blood sugar when they are unwell.

Medications: People with diabetes may use medication or insulin to manage blood glucose levels, and these can influence the patterns of blood glucose changes.

Do we all respond to food in the same way?

You may think that because we know what impacts blood glucose, we all respond in the same way to the food we eat and the activities we do. However the truth is, it's much more complex. We are all different and it’s simply not true that our bodies respond the same way to foods. Human responses to food can vary significantly from one individual to another, and these variations are influenced by a combination of genetic, environmental, and lifestyle factors. Here’s why:

Genetic Variability: Genetic factors play a substantial role in determining how our bodies metabolise and respond to different foods. Genetic variations can affect factors like insulin sensitivity, the ability to digest certain foods, and susceptibility to food allergies or intolerances.

Metabolic Rate: Each person's metabolism is unique. Some individuals have faster metabolisms, which means they burn calories more quickly, while others have slower metabolisms. This affects how the body processes and stores energy from food.

Insulin Sensitivity: People differ in their sensitivity to insulin, a hormone that regulates blood sugar levels. Insulin resistance can lead to blood sugar spikes after meals, and this can vary among individuals.

Food Allergies and Intolerances: Some people have allergies or intolerances to specific foods or food components, such as lactose or gluten. Consuming these foods can lead to adverse reactions that vary from person to person.

Microbiome Composition: The gut microbiome, the collection of microorganisms living in the digestive tract, varies from person to person. These microorganisms can influence digestion, nutrient absorption, and the body's response to different foods.

Age and Gender: Age and gender can affect how the body responds to food. For example, metabolism tends to slow down with age, and hormonal differences can influence food cravings and preferences.

Activity Level: Physical activity levels can impact how the body processes food. Regular exercise can improve insulin sensitivity and the body's ability to use nutrients efficiently.

Individual Preferences: Personal food preferences and cultural backgrounds also play a role in how individuals respond to foods. What one person finds enjoyable and satisfying may not be the same for someone else.

Health Conditions: Underlying health conditions, such as, but not limited to, diabetes, can significantly influence how the body responds to food.

Because of these individual differences, it's important to recognise that there is no one-size-fits-all approach to nutrition. Personalised dietary plans that take into account an individual's genetics, metabolic profile, health status, and personal preferences are often more effective for achieving health and dietary goals.

What is the connection between blood glucose and weight loss?

The connection between blood glucose and weight loss lies in the impact of blood sugar levels on your body's fat-burning mechanisms. When your blood glucose is elevated, your pancreas responds by releasing more insulin to transport the excess sugar from your bloodstream into your cells. However, this surge in insulin poses a challenge for weight loss because your body primarily burns fat when insulin levels decrease. If you consistently have high blood sugar levels, your body remains in a state of continuous insulin production, leading to the storage of excess sugar as unburned fat. As such, weight loss becomes quite challenging.

On the other hand, maintaining stable blood sugar levels prevents your cells from being overwhelmed by excessive insulin. This allows your body the opportunity to use its stored fat for energy between meals - which of course can contribute to weight loss.

How can blood glucose monitoring help with weight loss?

Blood glucose monitoring can be a valuable tool for weight loss because it provides insights into how your body responds to different foods and eating patterns. We know our bodies respond differently to the food we eat and the activities we do, so monitoring blood glucose can give us deep insight into our bodies. Blood glucose monitoring may help us to:

Identify problem foods: Blood glucose monitoring can show you how your body responds to different foods. You can pinpoint foods that cause rapid glucose spikes and adjust your diet accordingly.

Eat mindfully: Blood glucose data can help you eat more mindfully. It's easier to make healthier choices when you see how food affects your blood sugar. Monitoring your blood glucose can also help you learn about your body's hunger and satiety cues.

Control our portions: If you notice that specific meals lead to significant blood glucose increases, it can be a sign that you're eating too much. This insight can help with portion control and calorie management.

Make smarter food choices: You can choose foods that have a lower impact on your blood sugar. These are likely to be whole grains, lean proteins, and fibrous vegetables instead of highly processed and sugary foods.

Understand lifestyle impacts: Monitoring your blood glucose can help you understand the impact of various lifestyle factors, such as sleep, exercise, and stress, on blood sugar levels.

Knowing our blood glucose level doesn't help us to lose weight on its own, it's what you do with this new knowledge that counts.

Can you use a CGM for weight loss?

Yes, you can use CGMs to aid your weight loss journey. Many CGMs are designed with this in mind and have associated apps to help you make sense of the blood glucose data and should advise you on what the changes in your glucose levels mean for your weight goals.

However, before using CGM for weight loss, it's advisable to consult with a healthcare professional who can provide guidance on interpreting and using the data effectively and to ensure that it aligns with your overall health and weight loss goals.

Should I talk to my doctor about my blood glucose measurements?

If you are concerned about your blood sugar levels, then of course you should consult with your doctor or healthcare provider. However, the rise in continuous blood glucose monitoring products aimed at improving a healthy lifestyle (as opposed to treating diabetes) has led to a rise in patients visiting their doctors when they are healthy. Some people who use CGMs are alarmed at the data and don't fully understand what it tells them. As we discussed in this article, blood sugar levels naturally go up and down over the course of the day; this is normal. Knowing what’s normal for you may take some time, so try to remain calm about the new data that you are seeing, first consult with your CGM provider for guidance on how to interpret data. But yes, always consult your doctor if you feel worried or unwell.

So in summary, while blood glucose monitoring does not help you lose weight in and of itself, it can be a useful tool. CGMs can provide valuable insights into your body's response to food. As such, when combined with a balanced diet, regular exercise, and mindful eating, CGMs can support your efforts to lose unwanted weight and improve your overall health.

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