Diabetes occurs when your blood sugar levels rise to an unhealthy amount. Eating a balanced diet and getting enough exercise are the best ways to ensure your blood sugar remains constant. Find out more about the different types of diabetes, how to test for them, and how to keep your blood sugar levels in check.

What is blood sugar?

Blood sugar is the amount of glucose (a type of simple sugar) in your bloodstream. It’s also referred to as serum glucose level or blood glucose level.

Glucose is the main source of energy for both your brain and body. Glucose is stored in your body as glycogen, and typically, you will have about 4 grams in your body at all times.

You can check your blood sugar control over the last 3 months by using an HbA1c blood test.

Why is it important to keep blood sugar under control?

It’s important to control your blood sugar levels because if they become too low (hypoglycaemia) or too high (hyperglycaemia), it can have serious side effects. Because of this, your body works to keep your blood sugar levels steady at all times — a process called homeostasis. This is achieved by your pancreas releasing two hormones, insulin and glucagon. Insulin works to reduce blood sugar levels and glucagon to increase them.

If your blood sugar level is too low, your body produces glucagon to raise your sugar levels back to normal.

If your blood sugar level is too high, your body will start producing more insulin. Insulin stimulates your cells to take up sugar from your blood — which they use for energy.x

What causes your blood sugar levels to rise?

Your blood sugar levels can increase for various reasons, including:

  • eating a carbohydrate-rich meal
  • not exercising enough
  • having an infection or illness
  • changes in your hormone levels — for example, periods
  • stress

It's important to note that glucose isn’t bad for you. You need glucose to function — in fact, glucose is the main source of energy for both your body and brain.

Sugar cubes and red arrow pointing up on blue background

Diabetes is when your body struggles to produce or respond to insulin. This causes your blood sugar levels to rise to an unhealthy level — potentially harming your body.

Diabetes is divided into two types:

  • type 1 diabetes — an autoimmune disease that’s normally identified in early childhood. It happens when your immune system attacks and damages the production site of insulin until your body can no longer make it.
  • type 2 diabetes — this is when your body doesn’t produce enough insulin or your cells become resistant to it.

Find out more about the difference between type 1 and 2 diabetes.

Risk factors and causes of type 2 diabetes

Unlike type 1 diabetes, type 2 diabetes isn’t an autoimmune condition. It’s mostly influenced by lifestyle factors, as well as genetic factors.

You're at more risk of getting type 2 diabetes if:

  • you’re over 40 — you’re more likely to suffer from diabetes the older you get
  • one of your family members has it —you’re 2-6 times more likely to develop diabetes if one or more of your parents or siblings have it
  • you’re of South Asian, African Caribbean, or Black African descent — you’re up to four times more likely to develop type 2 diabetes
  • you smoke — smoking is associated with an increased risk of several medical conditions including type 2 diabetes.
  • you drink too much alcohol — the NHS recommends limiting your intake to 14 units of alcohol or under a week
  • have a sedentary lifestyle — refers to sitting down for a large part of the day, not including sleeping (you can still do regular exercise and lead a sedentary lifestyle)
  • you have high blood pressure — high blood pressure is considered to be 140/90mmHg or higher
  • you’re overweight — this is the main risk factor for insulin resistance

What are the symptoms of diabetes?

The signs and symptoms of diabetes can often be very subtle, meaning it can be up to 10 years before you realise you have it. Some of the most common symptoms include:

  • extreme thirst
  • urinating more often —mainly during the night
  • extreme tiredness
  • slower healing of cuts and wounds
  • blurry vision
  • increased infections — for example, thrush
  • unexplained weight loss

If you have any of these symptoms, you should see your GP.

How to test for prediabetes or diabetes

A number of blood tests can be done which can check for or indicate your risk for diabetes or prediabetes:

  • fasting insulin — a high fasting insulin result would indicate that you have insulin resistance
  • HbA1c — this blood test measures your average blood sugar levels over the last 3 months
  • oral glucose tolerance test (OGTT) — checks your blood sugar levels before and after you take glucose drink
  • homeostatic model assessment (HOMA) — measures your blood sugar and glucose levels

Long-term effects of type 2 diabetes

Type 2 diabetes can have some serious side effects if it’s not addressed and managed. In the worst-case scenario, the side effects include:

  • heart disease and stroke
  • kidney disease
  • diabetic retinopathy — when high blood sugar damages the back of your eye (retina)
  • nerve damage

How to prevent diabetes

The good news is that type 2 diabetes is preventable in most cases by following a healthy lifestyle.

Eat a healthy diet
Eat a healthy diet full of whole grains, fruits, vegetables, oily fish, nuts and seeds. Avoid having too many processed and sugary foods.

If you’re insulin resistant or have prediabetes or type 2 diabetes, you could try intermittent fasting — alternating between periods of fasting and periods of eating. There are a number of ways to do this so it’s important to research this method of eating first and speak with a health professional.

Avoid too much alcohol
Limit the amount of alcohol you have a week to 14 units — that’s equivalent to 6 pints of beer or 7 glasses of wine.

Exercise regularly
Aim to do at least 150 minutes of moderate-intensity or 75 minutes of high-intensity exercise a week. Exercise reduces blood sugar levels and is a great way to prevent or manage diabetes.

Avoid smoking
If you smoke, try to quit. Smoking has been heavily linked with an increased risk of various medical conditions, including type 2 diabetes.

Manage your weight
Check your waist size — a healthy waistline is a good indicator of whether or not you’re at risk of diabetes. Males should aim to be under 94cm (37ins) and females under 80cm (31.5ins).

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Diabetes.org. Type 2 diabetes. How can I reduce my risk of Type 2 diabetes? Retrieved July 2019 from https://www.diabetes.org.uk/preventing-type-2-diabetes/can-diabetes-be-prevented.

Diabetes.org. Type 2 diabetes. Diabetes risk and your waist measurement. Retrieved July 2019 from https://www.diabetes.org.uk/preventing-type-2-diabetes/waist-measurement.

NHS (2019). Type 2 diabetes. What is type 2 diabetes? Retrieved July 2019 from https://www.nhs.uk/conditions/type-2-diabetes/https://www.nhs.uk/conditions/type-2-diabetes.

NHS (2019). Type 2 diabetes. Health problems. Retrieved July 2019 from https://www.nhs.uk/conditions/type-2-diabetes/health-problems.

NHS (2019). Type 2 Diabetes. Symptoms of type 2 diabetes. Retrieved July 2019 from https://www.nhs.uk/conditions/type-2-diabetes/symptoms.