How Your Body Uses Energy: A Simple Guide to Blood Sugar and Metabolism
What is Metabolism, and Why Does it Matter?
Metabolism is the process your body uses to convert food into energy. Every time you eat, your body breaks down nutrients and either uses them immediately for energy or stores them for later. This process happens through a series of chemical reactions, with the ultimate goal of keeping your body functioning—whether you're walking, thinking, or even just breathing.
At the core of metabolism is cellular respiration, the process where cells extract energy from glucose (a type of sugar). This happens in tiny structures inside your cells called mitochondria—often referred to as the "powerhouses" of the cell. Through a combination of chemical reactions, glucose is broken down with the help of oxygen to produce adenosine triphosphate (ATP), the main energy carrier in the body.
For people with type 2 diabetes, the way their body handles glucose is disrupted. This means cells don’t always get the energy they need efficiently, while excess sugar lingers in the blood. Over time, this can cause serious health problems. Understanding how your body produces and uses energy can help you make choices that improve your blood sugar levels, increase your energy, and protect your long-term health.
Step 1: The Three Energy Sources – Which Does Your Body Prefer?
Your body can get energy from three types of nutrients: carbohydrates, fats, and proteins. Each one is used differently, depending on your body's needs and circumstances.
Carbohydrates are the body’s preferred energy source. They are quickly broken down into glucose, which can be used immediately for energy or stored for later. Foods high in carbohydrates include bread, pasta, rice, fruit, and sugary snacks.
Fats provide a long-term energy supply. They are more energy-dense than carbohydrates but take longer to break down. The body mostly relies on fat for fuel during low-intensity activities and when glucose levels are low (such as during fasting or long periods without eating).
Proteins are primarily used for building and repairing tissues, but in certain conditions (such as prolonged fasting or very low carbohydrate intake), they can be broken down into glucose through a process called gluconeogenesis.
Although the body can use all three sources for energy, carbohydrates are the most efficient fuel. This is because glucose can enter the bloodstream quickly and be delivered to cells for immediate energy. However, in people with type 2 diabetes, the way glucose is processed is impaired, leading to high blood sugar levels and insulin resistance.
Step 2: Carbohydrates and Blood Sugar – The Role of Glucose
When you eat carbohydrates, your digestive system breaks them down into simple sugars, mainly glucose. This glucose is then absorbed into the bloodstream, causing blood sugar levels to rise.
Normally, the body keeps blood sugar tightly regulated. As soon as glucose enters the bloodstream, the pancreas releases insulin, a hormone that tells cells to absorb the sugar and use it for energy. This ensures that blood sugar levels return to normal and that the body's cells receive the fuel they need.
However, in type 2 diabetes, this system doesn’t work as effectively. Either the pancreas does not produce enough insulin, or the body's cells become resistant to insulin’s effects. This means glucose stays in the bloodstream for longer, leading to high blood sugar levels, which can damage blood vessels, nerves, and organs over time.
Step 3: Insulin – The Key to Unlocking Energy
Insulin acts like a key, unlocking cells so that glucose can enter and be used for energy. When insulin binds to a cell, it triggers the activation of glucose transporters, which pull glucose from the blood into the cell.
For people without diabetes, this process happens efficiently. After a meal, insulin quickly directs glucose into muscle, liver, and fat cells, ensuring stable blood sugar levels. However, in insulin resistance, the cells do not respond well to insulin, meaning they do not absorb glucose as effectively. As a result, the pancreas produces even more insulin to compensate, but over time, it struggles to keep up.
This leads to two major problems:
Chronically high blood sugar levels, which increase the risk of complications like heart disease, nerve damage, and kidney disease.
Excess insulin production, which encourages fat storage and can lead to weight gain—particularly around the abdomen.
This is why managing insulin sensitivity through exercise, diet, and weight management is key to controlling type 2 diabetes and preventing complications.
Step 4: What Happens to Extra Sugar?
If you consume more carbohydrates than your body needs for immediate energy, your body stores the extra glucose in two ways:
Short-term storage (Glycogen):
Some glucose is stored in the liver and muscles as glycogen, a quick-release energy reserve.
Liver glycogen can be broken down and released into the bloodstream when needed (e.g., during fasting or between meals).
Muscle glycogen is used specifically by muscles during activity.
Long-term storage (Fat deposition):
When glycogen stores are full, excess glucose is converted into fat through a process called lipogenesis.
This fat is stored in adipose tissue (body fat) and can be used for energy later—but only if the body requires it.
If excess glucose is continuously converted into fat, weight gain occurs, particularly around the abdomen, increasing the risk of insulin resistance.
When insulin levels are high due to poor glucose regulation, the body prioritises storing fat instead of burning it, making it harder to lose weight. This is why insulin resistance and obesity often go hand in hand.
How You Can Improve Energy Use and Blood Sugar Control
Since type 2 diabetes alters the way the body processes glucose, two of the most effective ways to improve blood sugar control are exercise and smart nutrition choices.
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Physical activity helps improve glucose uptake by increasing the number of glucose transporters in muscle cells—meaning more sugar is absorbed from the blood without needing extra insulin. This makes insulin work more efficiently and lowers blood sugar naturally.
Walking after meals can reduce blood sugar spikes.
Strength training increases muscle mass, which helps store and use glucose more effectively.
Regular movement makes cells more sensitive to insulin, reducing insulin resistance over time.
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Choose complex carbs (whole grains, legumes, and vegetables) instead of refined sugars to slow digestion and prevent blood sugar spikes.
Pair carbohydrates with protein or healthy fats to keep energy levels stable.
Eat smaller, more frequent meals to avoid extreme blood sugar fluctuations.
The Bottom Line
Understanding how your body processes and uses energy is essential for managing type 2 diabetes. Blood sugar control is not just about avoiding sugar—it’s about optimizing how your body stores and uses glucose. The good news? Exercise and nutrition can restore this balance, improving insulin function, increasing energy levels, and reducing the risk of complications.
If you want to move better, feel stronger, and take control of your blood sugar, a diabetes-specific group exercise program is the perfect place to start.
Join today and start feeling the difference!
