What Is Prediabetes?
Prediabetes is when your blood sugar level is higher than it should be but not high enough for your doctor to diagnose diabetes. They might call it impaired fasting glucose or impaired glucose tolerance.
People with type 2 diabetes almost always had prediabetes first. But it doesn’t usually cause symptoms. About 84 million people over age 20 in the U.S. have prediabetes, but 90% don’t know that they have it.
Prediabetes treatment can prevent more serious health problems, including type 2 diabetes and problems with your heart, blood vessels, eyes, and kidneys.
Symptoms of Prediabetes
If you have symptoms, you might notice that:
Prediabetes Causes and Risk Factors
You’re more likely to get prediabetes if you:
- Are older, especially over age 45
- Have a waist larger than 40 inches around if you’re a man and 35 inches around if you’re a woman.
- Eat a lot of red and processed meat, drink sugary beverages, and don’t eat much fruit, veggies, nuts, whole grains, or olive oil
- Are Black, Native American, Latino, or Pacific Islander
- Are overweight or obese, especially if you have extra pounds around your middle (belly fat)
- Have high cholesterol, high triglycerides, low HDL cholesterol, and high LDL cholesterol
- Don't exercise
- Had gestational diabetes or gave birth to a baby who weighed more than 9 pounds
- Have polycystic ovary syndrome
- Have a sleep problem, like sleep apnea, or work changing shifts or night shifts
Get tested for prediabetes if those things apply to you and if you:
- Have had an unusual blood sugar reading
- Have heart disease
- Show signs of insulin resistance, which means your body makes insulin but doesn't respond to it the way it should. These include darkened areas of skin, trouble concentrating, and more fatigue or hunger than usual.
Tests and Diagnosis for Prediabetes
Your doctor will do at least one of these tests:
Fasting plasma glucose test. You won’t eat for 8 hours, and then a technician will take your blood to test the sugar levels. The results are:
- Normal if your blood sugar is less than 100 milligrams per deciliter (mg/dL)
- Prediabetes if your blood sugar is 100 to 125 mg/dL
- Diabetes if your blood sugar is 126 mg/dL or higher
Oral glucose tolerance test. First, you'll have a fasting plasma glucose test. Then, you'll drink something sugary. Two hours after that, a technician will take and test more blood. The results are:
- Normal if your blood sugar is less than 140 mg/dL after the second test
- Prediabetes if your blood sugar is 140 to 199 mg/dL after the second test
- Diabetes if your blood sugar is 200 mg/dL or higher after the second test
Hemoglobin A1c test. This blood test shows your average blood sugar levels for the past 2 to 3 months. Doctors give it to people who have diabetes to see if their blood sugar levels are under control. They can also use it to diagnose prediabetes or diabetes. The results are:
- Normal if it’s 5.6% or less
- Prediabetes if it’s 5.7 to 6.4%
- Diabetes if it’s 6.5% or above
You may need to take the test again to confirm the results.
Children and Prediabetes Testing
Doctors diagnose prediabetes based on the same blood sugar levels, no matter the person’s age. The American Diabetes Association says children 10 and older should be tested if they’re overweight or obese and have:
- A family member with type 2 diabetes
- A mother who had gestational diabetes while pregnant with the child
- Native American, Black, Hispanic, Asian American, or Pacific Islander heritage
- Signs of insulin resistance or conditions linked to it, such as a low birth weight, high blood pressure, or polycystic ovary syndrome
If a child who has a high chance of getting prediabetes has normal test results, the American Diabetes Association advises testing them again at least every 3 years.
Without treatment, prediabetes can become type 2 diabetes or cause other serious problems including:
- Kidney disease
- High blood pressure
- Nerve problems (peripheral neuropathy)
- Loss of a limb (amputation)
Treatment to Reverse Prediabetes
Take these steps to treat prediabetes:
- Eat a healthy diet and lose weight. Losing 5% to 10% of your weight can make a huge difference.
- Exercise. Pick something you enjoy, like walking. Try to get at least 30 minutes a day, 5 days a week. You can start with less time and work your way up to a half-hour if you need to. Check with your doctor before you do more than that.
- Stop smoking.
- Get your blood pressure and cholesterol under control.
- Take medication like metformin (Glucophage) to lower your blood sugar if you’re at high risk of diabetes.
Is There a Prediabetes Diet?
There’s no official diet, but four swaps can reverse prediabetes and lower your chances of getting type 2 diabetes:
- Choose whole grains and whole-grain products over processed carbs like white bread, potatoes, and breakfast cereals.
- Drink coffee, water, and tea instead of sugary drinks.
- Choose good fats like those in vegetable oil, nuts, and seeds over those in margarine, baked goods, and fried foods.
- Trade red meat and processed meats for nuts, whole grains, poultry, and fish.
Exercising and eating foods low in carbohydrates, sugars, fats, and salt can also help prevent prediabetes. Other tips include:
- Don’t smoke.
- Don’t have more than one alcoholic drink a day.
- Take blood sugar medications as your doctor prescribes.