What We’ll Cover

• How glucose works as the body’s energy source.
• The role of insulin in regulating glucose levels.
• Why monitoring blood sugar is key for managing T2DM.

What is glucose?‍

Glucose is the main type of sugar that the human body uses for energy. The word “glucose” comes from the Greek word for sweet – ‘glykós’.

Your body gets glucose from the foods you eat, mainly carbohydrates. After a meal, your digestive system breaks down these carbohydrates into glucose, which enters your bloodstream and raises your blood sugar levels (sometimes referrd to as blood glucose levels). This process is an essential part of your body’s metabolism.

The role of insulin in glucose regulation‍

When glucose levels in your blood rise after a meal, your pancreas releases a hormone called insulin. Insulin is essential for keeping blood sugar levels balanced.

Here’s how it works:

• Energy use: Insulin helps your cells absorb glucose from the bloodstream so they can use it for energy.
• Storage: It signals your liver to store extra glucose for later use and encourages your muscles and fat tissues to store glucose as glycogen or convert it into fat.

This second point is extremely important, as our muscles can only store a limited amount of glycogen. This means that when we eat more carbohydrates than we need, this is then stored as fat around the body.

T2DM, prediabetes, and hyperglycemia

When the body doesn’t produce enough insulin, or when insulin doesn’t work properly (insulin resistance), glucose remains in the bloodstream. This leads to high blood sugar levels, known as hyperglycemia. Over time, hyperglycemia can cause serious health complications if left unmanaged.

In people with type 2 diabetes (T2DM), the combination of reduced insulin production and insulin resistance makes it difficult to regulate blood sugar. Hyperglycemia is a defining feature of T2DM.

Before T2DM develops, many people experience prediabetes, where blood sugar levels are higher than normal but not yet high enough for a diabetes diagnosis. Prediabetes is an important warning sign and offers a chance to take steps to prevent the progression to T2DM.

Blood sugar levels are commonly assessed using the HbA1c test, which provides an average of blood glucose levels over the past three months. In the UK, HbA1c levels are measured in millimoles per mole (mmol/mol), with the following reference ranges:

• Normal: Below 42 mmol/mol (6.0%)
• Prediabetes: 42–47 mmol/mol (6.0%–6.4%)
• Type 2 diabetes: 48 mmol/mol (6.5%) or higher

Understanding your HbA1c levels can help identify prediabetes or T2DM and guide decisions for treatment and lifestyle changes to manage or reverse high blood sugar levels.

Summary
Glucose is the body’s main energy source, but it needs insulin to enter your cells and be used effectively. In type 2 diabetes (T2DM), reduced insulin production and insulin resistance result in high blood sugar levels, a condition known as hyperglycemia. Hyperglycemia can cause serious health complications if not managed properly.

For many, the journey to T2DM begins with prediabetes, where blood sugar levels are elevated but not yet in the diabetic range. Identifying this early through tests like HbA1c can help prevent progression. Monitoring blood sugar levels using HbA1c tests, finger-prick testing, or continuous glucose monitors (CGMs) is essential. These tools help track progress, evaluate treatment effectiveness, and personalise your care plan to manage or reverse the condition effectively.