What is prediabetes?

Prediabetes means that your blood glucose (sugar) levels are higher than normal but not high enough to be considered diabetes. Having prediabetes puts you at high risk for developing diabetes.

Most people with prediabetes and type 2 diabetes have a condition called insulin resistance. If you have insulin resistance, your body can't use insulin properly.

At first, the pancreas produces more insulin to overcome this problem. Over time, the pancreas can't keep up and extra glucose builds up in the bloodstream.

The main causes of insulin resistance are heredity (passed on in the family) and being overweight.

Other causes can include high blood pressure or high cholesterol levels.

There are two types of prediabetes:

  • impaired fasting glucose (known as IFG) Your blood glucose is too high in the morning after fasting (not eating or drinking) for eight to 12 hours.
  • impaired glucose tolerance (known as IGT) Your blood glucose is too high during the day after eating.

Fasting test

Non-fasting test

Normal less than 100 mg/dL less than 140 mg/dL
Prediabetes 100-125 mg/dL (too high in the morning) 140-199 mg/dL (too high during the day)
Diabetes 126 mg/dL or higher 200 mg/dL or higher

Glucose: When food is digested, it turns to sugar, called glucose. Body cells use glucose for fuel, giving you the energy you need.

Insulin: A hormone made by the pancreas that helps glucose move into body cells.

Source: Allina Health's Patient Education Department, Prediabetes: Reducing Type 2 Diabetes Risk Through a Lifestyle of Good Nutrition and Activity, first edition, dia-ah-94403
Reviewed By: Allina Health Patient Education
First Published: 04/02/2009
Last Reviewed: 01/28/2019