What Is Impaired Fasting Glucose?

Impaired fasting glucose is a type of prediabetes in which blood sugar levels are higher than normal but lower than the threshold to be diagnosed with diabetes. This type of prediabetes is determined when blood sugar levels are tested after fasting, which is going at least eight hours without food.

Impaired fasting glucose can be an early warning sign for a serious medical condition called type 2 diabetes. People with type 2 diabetes have high blood sugar levels because their bodies do not respond properly to insulin, a hormone that lowers blood sugar levels.

Learn about impaired fasting glucose, the symptoms, treatment, coping, and more.

Types of Prediabetes

Prediabetes occurs when blood sugar levels are higher than normal but lower than diabetic levels. Two blood tests can inform prediabetes: impaired fasting glucose and impaired glucose tolerance.

Impaired fasting glucose is a blood test taken after going eight hours without food. Impaired glucose tolerance is a blood test that compares blood sugar levels after fasting with levels two hours after drinking a specific sugary drink.

Prediabetes, whether identified as impaired fasting glucose or impaired glucose tolerance, can lead to type 2 diabetes, but not type 1 diabetes.

Impaired Fasting Glucose Symptoms

Since impaired fasting glucose and diabetes both involve elevated blood sugar levels, symptoms can be similar.

Symptoms of high blood sugar may include:

• Changes in vision
• Increased need to urinate
• Thirst
• Weakness or fatigue
• Weight loss

Approximately 8 out of 10 people with prediabetes do not know they have the condition. This is because symptoms don't usually appear until blood sugar levels increase enough to be diagnosed with diabetes.

Diagnosis

Impaired fasting glucose is diagnosed with a blood test that checks blood glucose levels after eight hours without food. This is called a fasting plasma glucose test, or FPG. A result of 100 mg/dl (milligrams per deciliter) to 125 mg/dl is considered prediabetes. Lower than 100 mg/dl is normal and higher than 125 mg/dl is considered diabetes. Two tests with results in the same range may be required to confirm a diagnosis.

Treatment

People with impaired fasting glucose usually do not need to be medically treated because the condition is relatively mild compared to diabetes.

However, people with prediabetes should be closely monitored so that if the condition worsens and medication is needed, it can be given right away. Until then, it is crucial to be physically active and eat the right amount of healthy foods to lose weight, treat prediabetes, and reduce the risk of developing diabetes.

Prognosis

Approximately 1 in 4 people with impaired fasting glucose and prediabetes will get a diabetes diagnosis within five years. This is partly because about 8 out of 10 people with prediabetes don't know they have the condition and are unaware that lifestyle changes can vastly decrease their risk for diabetes.

Lifestyle changes, such as diet and exercise, can decrease the risk of prediabetes leading to diabetes up to 58% for people under age 60 and up to 71% for people over age 60.

Coping

The best way to cope with impaired fasting glucose is to make lifestyle changes that improve health and lead to weight loss.

Lifestyle changes that help to lose weight and prevent diabetes include:

• Being physically active
• Limiting alcohol and sugary or processed foods
• Abstaining from smoking

People with prediabetes and diabetes are at an increased risk of depression, anxiety, and other mental health challenges. Reaching out for support with any mental health challenges that may come with impaired fasting glucose is essential.

Summary

Impaired fasting glucose, or prediabetes, is a medical condition that can lead to diabetes. It can be detected with a fasting plasma glucose test, which measures blood sugar levels after going without food for eight hours. Like diabetes, impaired fasting glucose involves high blood sugar levels, but they are not high enough to be diagnosed as diabetes.

Most people do not have symptoms. Still, it is essential to make lifestyle changes such as increasing physical activity and eating the right amount of healthy foods to lose weight and prevent diabetes. With these changes, many people can reverse prediabetes and reduce their risk of developing diabetes.

A Word From Verywell

It can be challenging to face a diagnosis of impaired fasting glucose. Fortunately, a lot can be done to reverse the condition and prevent it from escalating to diabetes. If you or someone you know has been diagnosed with impaired fasting glucose, help is available. Reach out to a healthcare professional for support with lifestyle changes, weight loss, and coping strategies.