Defeat Diabetes

How a low carb diet can help to manage blood sugar levels

4 mins read

When first diagnosed with diabetes, you might have been prescribed medication and advised to see a dietitian or diabetes educator. Your doctor might have told you that your condition would slowly worsen and your risk of developing heart disease, stroke or amputations would increase. 

It’s unlikely anyone told you that a small change to how you eat would help manage your blood glucose and could help you return to pre-diabetic levels, known as remission.  

And yet, a small change to our eating habits can dramatically improve our blood glucose levels. Here’s how. 

First, what does blood sugar do? 

The human body is a complex machine, and your blood sugar is the engine that drives it. Blood sugar is the amount of glucose (or sugar) in our bloodstream, which we can use for energy, and keeping it balanced is crucial to maintaining health. 

Blood sugar rises when we eat foods containing sugar, like lollies and processed foods. But it also increases when we eat carbohydrates: starchy veg like potatoes, bread and pasta.

When we eat too much sugar, our pancreas struggles to release enough insulin to transport the sugars to our cells for energy. Over years of eating this way, we eventually become insulin-resistant and can no longer process the glucose in our bloodstream. When we can no longer process glucose, it causes damage throughout the body and increases our risk of diseases like kidney disease, heart disease and non-alcoholic fatty liver disease. 

What are carbs?

Carbohydrates come in three forms: sugars, starches, and fibre. All will raise blood sugar levels, some faster than others:

    1. Added Sugars

    Unsurprisingly, sugary foods such as cakes, biscuits, and soft drinks lead to swift increases in blood sugar levels. Look for ingredients like sugar, corn syrup, dextrose, sucrose, or fructose on food labels - but be aware that manufacturers can use 56 different names for sugar! Check the carb content on your labels, and look for foods with less than 20 grams of carbs per 100 grams. 

A woman eating a large piece of cake
Party food including sandwiches

2. Starches

Generally, less processed starches (those that most closely resemble their natural state) tend to have a smaller impact on blood sugar levels. Examples include brown rice, lentils and oats. However, these carbohydrates will still impact your blood sugar and should be avoided. Highly processed starches like white rice (where the fibrous husk is removed) and bread lead to rapid spikes in blood sugar.

3, Fibre

A fibre-rich diet is helpful for people living with diabetes, as it helps regulate blood sugar levels. Fibre in foods slows down the conversion of carbohydrates into sugar, resulting in a less pronounced blood sugar peak. Excellent sources of fibre include green leafy vegetables, avocados, nuts and seeds. Additionally, fibre imparts a sense of fullness and promotes a healthy digestive system.
Crate of fresh vegetables

The effect of low carb eating on blood sugar levels

Low carb eating controls blood sugar levels primarily because it minimises carb intake and digestion, reducing unwanted blood glucose spikes and improving insulin sensitivity. “We know that if you reduce the amount of carbs you eat, you can maintain a relatively stable blood sugar level,” explains Dr. Peter Brukner. “The biggest impact on whether your pancreas releases insulin is the presence of sugar. As soon as sugar – or carbs – hits the bloodstream, you need insulin to counteract it. Fewer carbs mean less insulin is required.” 

What blood sugar level should you aim for?

First thing in the morning and before meals:

A normal fasting blood sugar level in someone who does not have diabetes is generally between 4.0 and 7.8 mmol/L (Diabetes Australia).

2-3 hours after a meal:

Blood sugar levels will always rise after meals but may peak at different times. How much and quickly your blood sugar level increases after eating is mainly due to your body’s ability to handle carbs. Generally speaking, blood sugar levels between 5.0 to 10 mmol/L are seen 2-3 hours after starting a meal. 

Other factors that can affect blood sugar levels

It’s one of the easiest things to control, but food is just one factor that can raise or lower blood sugar levels. The following list is not exhaustive, but the main culprits for affecting your blood sugar levels include:

  1. Physical activity: Exercise can raise or lower blood sugar levels, depending on the type, intensity and duration. Aerobic activities tend to lower blood sugar, while intense or prolonged exercise can cause a temporary increase in blood sugar due to the release of stress hormones.
  2. Stress: Stress triggers the release of hormones like cortisol and adrenaline, which can lead to higher blood sugar levels. This is often referred to as the “fight or flight” response.
Woman stressed, worried looking downwards
  1. Illness or infection: When the body fights an illness or infection, it releases hormones that can elevate blood sugar levels. This is why monitoring blood sugar levels closely during illness is important.
  2. Hormones: Hormonal changes, such as those associated with menstruation or menopause, can affect blood sugar control.
  3. Lack of sleep: Inadequate or disrupted sleep patterns can lead to higher blood sugar levels. The body’s ability to use insulin efficiently is reduced when we sleep poorly.
  4. Other medical conditions include polycystic ovary syndrome (PCOS), thyroid disorders, and hormonal imbalances that can contribute to higher blood sugar levels.
  5. Alcohol: Too much alcohol can disrupt blood sugar levels. At first, alcohol may cause a drop in blood sugar, as the liver will always process alcohol first and stop releasing glucose. However, most alcoholic drinks are high in carbs, which will spike blood sugar levels. 
  6. Dehydration: When the body is dehydrated, blood sugar levels can become more concentrated, potentially leading to higher readings.
Man standing outside on a hot day wiping face dehydrated thirsty
  1. Medications: Some medications, particularly those used to manage mental health conditions like schizophrenia or bipolar disorder and corticosteroids, may impact blood sugar levels.
  2. Smoking: Smoking can damage cells, so they don’t respond to insulin. This, in turn, leads to insulin resistance, as well as increased inflammation.
  3. Temperature: Extreme temperatures, especially hot weather, can affect blood sugar levels. High temperatures not only dilate blood vessels, enhancing insulin absorption but may also lead to dehydration, which can, in turn, affect blood sugar concentrations.


Think of your insulin like a petrol tank. There’s a finite amount, and you don’t want it to run out. That’s what happens with insulin resistance. The insulin doesn’t work properly to counteract the high glucose or sugar levels in the blood. The best way to avoid insulin resistance and type 2 diabetes is by keeping your blood sugar levels steady and in the normal range so you’re not having to call upon your pancreas to produce insulin so often. 

Eating low carb foods is the simplest way to keep blood sugar levels stable. Foods low in carbs don’t spike blood sugar levels and, therefore, don’t require an insulin response. 

If you’re unsure how to start eating low carb, why not try the Defeat Diabetes low carb program free for 14 days and see how you feel? Defeat Diabetes member Sharon was surprised at how quickly her blood sugar levels dropped after starting the program: “On the first morning, my fasting glucose was 10.6. After 17 days, my fasting levels are down to low 5s every morning. 

“I’ve even had a few days where my levels were in the 4s. I know it will keep improving each day. I feel like I’m healing.”

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