What is type 2 diabetes?

Almost one million people in Australia have type 2 diabetes, but about half of them may not know they have it.

Type 2 diabetes is sometimes called adult- or maturity-onset diabetes. This is because it usually first appears in middle-aged or older people, although it is becoming more common in children and adolescents with a family history of type 2 diabetes and/or those who come from a high-risk group (such as Aboriginal and Torres Strait Islander people, people who are obese or those who have a history of gestational diabetes).

In type 2 diabetes, the body either doesn’t release enough insulin or the body makes insulin in normal amounts, but the body’s cells do not respond to it. This results in higher than normal levels of glucose (a type of sugar) in the blood.

The high blood glucose levels that occur as a result of diabetes can cause a range of different symptoms (such as urinating frequently, thirst and weight loss). If not controlled, over time, these may cause problems and complications, such as vision loss, kidney disease, foot and leg problems, and an increased risk of stroke and heart disease.

Apart from type 2 diabetes, there are also two other main types of diabetes:

In type 1 diabetes, the body makes little or no insulin. To find out more, read our information on type 1 diabetes. Gestational diabetes is similar to type 2 diabetes, but only occurs in women during pregnancy.

What happens in type 2 diabetes?

In people with diabetes, the body’s usual ways of controlling blood glucose levels do not work properly, which results in high blood glucose.

When you eat food, it is digested in the stomach, which then transports any glucose (a type of sugar) — and other nutrients that the food contains — into your blood. The glucose is used by your body as energy for a whole range of important processes, including providing your muscles with energy during exercise.

Normally, insulin controls the amount of glucose in the blood and keeps it at a safe and healthy level. Normal glucose levels are between 4.0 and 8 millimoles [mmol] per litre [L].

Insulin helps glucose to enter the body’s cells and is also involved in storing excess glucose in the liver, and in the fatty (adipose) tissues of the body. It is produced by the pancreas when blood glucose levels rise — for example after a meal.

In type 2 diabetes, one of two things can happen: either the pancreas doesn’t make enough insulin, or the cells in the body that take up and store glucose (e.g. the liver and fatty tissues) don’t respond properly to the insulin made by the pancreas (this is known as ‘insulin resistance’). In both cases, the end result is higher than normal blood glucose levels (more than 8 mmol of glucose per litre of blood).

If you would like to find out more, read our information about insulin and the pancreas.

If you are living with type 2 diabetes, your treatments will usually include both lifestyle changes and diabetes medicines.

A healthy lifestyle is vital for everyone with diabetes

Maintaining a healthy lifestyle and healthy glucose levels are key for people living with diabetes. It’s important to:

  • follow a healthy diet
  • be physically active (ideally for at least 30 minutes 5 days per week)
  • have regular health checks
  • limit alcohol
  • quit smoking
  • regularly check glucose levels when recommended.

Read or download our fact sheet Managing type 2 diabetes — your lifestyle to find out simple but effective lifestyle changes you can make to improve your health and help manage your diabetes, as well as helping to keep your blood pressure, cholesterol and blood glucose levels as close as possible to your target range.