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

There are 2 main types of diabetes:

  • type 1 diabetes – a lifelong condition where the body’s immune system attacks and destroys the cells that produce insulin
  • type 2 diabetes – where the body does not produce enough insulin, or the body’s cells do not react to insulin properly

Type 2 diabetes is far more common than type 1. In the UK, over 90% of all adults with diabetes have type 2.

High blood sugar that develops during pregnancy is known as gestational diabetes. It usually goes away after giving birth.

Type 1 diabetes

Type 1 diabetes is where your blood glucose (sugar) level is too high because your body can’t make a hormone called insulin.

This happens because your body attacks the cells in your pancreas that make the insulin, meaning you can’t produce any at all.

We all need insulin to live. It does an essential job. It allows the glucose in our blood to enter our cells and fuel our bodies.

When you have type 1 diabetes, your body still breaks down the carbohydrate from food and drink and turns it into glucose. But when the glucose enters your bloodstream, there’s no insulin to allow it into your body’s cells. More and more glucose then builds up in your bloodstream, leading to high blood sugar levels.

Type 2 diabetes

With type 2 diabetes the insulin your pancreas makes can’t work properly, or your pancreas can’t make enough insulin. This means your blood glucose (sugar) levels keep rising. 

Around 90% of people with diabetes in the UK have type 2. It is serious condition and can be lifelong. 

Having type 2 diabetes without treatment means that high sugar levels in your blood can seriously damage parts of your body, including your eyes, heart and feet. These are called the complications of diabetes. But with the right treatment and care, you can live well with type 2 diabetes and reduce your risk of developing them.

Gestational diabetes

Gestational diabetes is diabetes that can develop during pregnancy. It affects women who haven’t been affected by diabetes before. It means you have high blood sugar and need to take extra care of yourself and your bump. This will include eating well and keeping active.

It usually goes away again after giving birth. It is usually diagnosed from a blood test 24 to 28 weeks into pregnancy.


Prediabetes means that your blood sugars are higher than usual, but not high enough for you to be diagnosed with type 2 diabetes. It also means that you are at high risk of developing type 2 diabetes. You are unlikely to be experiencing any symptoms with prediabetes.

Prediabetes is also sometimes called borderline diabetes. Higher than normal blood sugars can be detected via blood tests. The medical terms for higher-than-normal blood sugars are:

  • Impaired Fasting Glucose (IFG)
  • Impaired Glucose Tolerance (IGT)
  • Impaired Glucose Regulation (IGR)
  • Non-diabetic hyperglycaemia

Living with diabetes

If you’re diagnosed with diabetes, you’ll need to eat healthily, take regular exercise and have regular checks including blood tests.

You can use the BMI healthy weight calculator to check whether you’re a healthy weight.

Try to quit smoking if you smoke, and cut down on alcohol.

People diagnosed with type 1 diabetes also require regular insulin injections for the rest of their life.

Type 2 diabetes can get worse over time and people living with type 2 diabetes often need medicine, usually in the form of tablets or injections.

However, some people can put their type 2 diabetes into remission by losing weight, where their blood sugar is reduced below the diabetes range. Some people are able to do this through a low-calorie diet, but this is not suitable for everyone, so it’s important to get medical advice first.

Religious fasting and diabetes

Fasting is an important spiritual aspect of many religions but it can lead to major health problems for some people with diabetes.

Diabetes UK have developed a series of information resources about religious fasting and diabetes.

The Islamic month of Ramadan is one of the longest periods of fasting. Diabetes UK have specific advice on fasting and diabetes and fasting during Ramadan.

They have produced a factsheet about diabetes and Ramadan, which includes information about fasting and managing your diabetes during this time. This has been developed in partnership with the British Islamic Medical Association (BIMA). 

It is available to order and download in EnglishArabicBengaliGujarati and Urdu to share with friends or family.  

Educational Videos

The NHS Diabetes Prevention Programme story

What Is Diabetes? | 2 Minute Guide | Diabetes UK

What Is Type 1 Diabetes? | 2 Minute Guide | Diabetes UK

What Is Type 2 Diabetes? | 2 Minute Guide | Diabetes UK

Exercise and diabetes | Tips for increasing activity levels | Sarah’s Story | Diabetes UK

Diabetes and blood pressure | How it works | Diabetes UK

Diabetes and cholesterol | How it works | Diabetes UK

What is diabetes remission? | Type 2 diabetes remission explanation | Diabetes UK

Page last reviewed: 19 March 2024