Diabetes is a lifelong condition that causes a person's blood sugar level to become too high.

The hormone insulin – produced by the pancreas – is responsible for controlling the amount of glucose in the blood

There are two main types of diabetes:

  • type 1 – where the pancreas doesn't produce any insulin
  • type 2 – where the pancreas doesn't produce enough insulin or the body's cells don't react to insulin

This topic is about type 2 diabetes. Read more about type 1 diabetes.

Another type of diabetes, known as gestational diabetes, occurs in some pregnant women and tends to disappear after birth.

Symptoms of diabetes

The symptoms of diabetes occur because the lack of insulin means glucose stays in the blood and isn't used as fuel for energy.

Your body tries to reduce blood glucose levels by getting rid of the excess glucose in your urine.

Typical symptoms include:

  • feeling very thirsty
  • passing urine more often than usual, particularly at night
  • feeling very tired
  • weight loss and loss of muscle bulk

Read more about the symptoms of type 2 diabetes.

It's very important for diabetes to be diagnosed as soon as possible as it will get progressively worse if left untreated.

Read about how type 2 diabetes is diagnosed.

Causes of type 2 diabetes

Type 2 diabetes occurs when the body doesn't produce enough insulin to function properly, or the body's cells don't react to insulin. This means glucose stays in the blood and isn't used as fuel for energy.

Type 2 diabetes is often associated with obesity and tends to be diagnosed in older people. It's far more common than type 1 diabetes.

Read about the causes and risk factors for type 2 diabetes.

Treating type 2 diabetes

As type 2 diabetes usually gets worse, you may eventually need medication – usually tablets – to keep your blood glucose at normal levels.

Read more about the treatment of type 2 diabetes.

Complications of type 2 diabetes

Diabetes can cause serious long-term health problems. It's the most common cause of vision loss and blindness in people of working age.

Everyone with diabetes aged 12 or over should be invited to have their eyes screened once a year for diabetic retinopathy.

Diabetes is also responsible for most cases of kidney failure and lower limb amputation, other than accidents.

People with diabetes are up to five times more likely to have cardiovascular disease, such as a stroke, than those without diabetes.

Read more about the complications of type 2 diabetes.

Preventing type 2 diabetes

If you're at risk of type 2 diabetes, you may be able to prevent it developing by making lifestyle changes.

These include:

Living with type 2 diabetes

If you already have type 2 diabetes, it may be possible to control your symptoms by making the above changes. This also minimises your risk of developing complications.

Read more about living with type 2 diabetes.

Diabetes 'sick day rules'

If you need to take insulin to control your diabetes, you should have received instructions about looking after yourself when you're ill – known as your "sick day rules".

Contact your diabetes care team or GP for advice if you haven't received these.

The advice you're given will be specific to you, but some general measures that your sick day rules may include could be to:

  • keep taking your insulin – it's very important not to stop treatment when you're ill; your treatment plan may state whether you need to temporarily increase your dose
  • test your blood sugar level more often than usual – most people are advised to check the level at least four times a day
  • keep yourself well hydrated – make sure you drink plenty of sugar-free drinks
  • keep eating – eat solid food if you feel well enough to, or liquid carbohydrates such as milk, soup and yoghurt if this is easier
  • check your ketone levels if your blood sugar level is high

Seek advice from your diabetes care team or GP if your blood sugar or ketone level remains high after taking insulin, if:

Page last reviewed: 27/06/2016

Next review due: 27/06/2019