Borderline diabetes, also called prediabetes, is a condition that often develops before someone gets type 2 diabetes. It’s also known as impaired fasting glucose or glucose intolerance. It basically means your blood sugar levels are higher than normal, but they’re not quite high enough to be considered diabetes.

During the prediabetes phase, your pancreas usually still produces enough insulin in response to ingested carbohydrate. The insulin is less effective at removing the sugar from the bloodstream, though, so your blood sugar remains high. This condition is called insulin resistance.

To determine your blood glucose levels, your doctor will perform a fasting blood glucose test. This is a relatively simple test. After an overnight fast or a fast of 8 hours, your doctor will draw your blood. Using this blood sample, your sugar levels will be tested. The amount of sugar in your blood will determine if you have borderline diabetes or diabetes.

Alternatively, your doctor may instead perform a hemoglobin A1c (HbA1c) test or an oral glucose tolerance test (OGTT). HbA1c is an indicator of your blood sugar patterns over the last two to three months, so it is often a better overall picture than a single fasting blood sugar check. An HbA1c level between 5.7 and 6.4 indicates prediabetes.

ConditionBlood Sugar Levels
Normal Fasting Blood GlucoseBelow 100 mg/dL
Borderline Diabetes Fasting Blood GlucoseBetween 100 mg/dL and 126 mg/dL
Diabetes Fasting Blood GlucoseAbove 126 mg/dL

If you have prediabetes, you should know you’re not alone. In 2012, it was estimated that 86 million people age 20 and older had the condition. That’s one in three Americans.

Having prediabetes doesn’t mean you’ll definitely develop diabetes. It is a warning of what could lie ahead, however. People with prediabetes have a five to 15-fold higher risk for type 2 diabetes than someone with normal blood sugar levels. Those chances increase if you don’t make any healthy changes to your diet or activity habits.

Early Warning Signs

“Prediabetes is not pre-problem,” says Jill Weisenberger, M.S., R.D., C.D.E., and author of “Diabetes Weight Loss Week by Week.”

Someone with insulin resistance in its early stages can develop type 2 diabetes if it continues long enough. Only 10 percent of people with prediabetes even know they have it because people often do not display any symptoms. If there are symptoms, they can easily be mistaken for another cause.

If you have prediabetes, you may have one or more of these symptoms:

  • increased thirst
  • tiredness
  • blurry vision
  • cuts that won’t heal
  • gum inflammation

You may exhibit no symptoms, however.

“Often, people consider these symptoms part of their normal day, so they’re ignored,” says Toby Smithson, R.D.N., C.D.E., a spokesperson for the Academy of Nutrition and Dietetics and co-author of “Diabetes Meal Planning and Nutrition for Dummies.”

Borderline Diabetes Risk Factors

Any of these risk factors can increase your chances of developing prediabetes:

  • being overweight or obese
  • being inactive
  • high blood pressure
  • high cholesterol
  • having a close family member with type 2 diabetes
  • giving birth to a baby weighing more than 9 pounds

Take Control

Prediabetes can be a silent condition, so getting a regular wellness checkup is important for early detection. If you think you might have borderline diabetes, discuss your concerns with your doctor.

If there’s concern, your doctor will order one of three tests:

  • a fasting blood glucose test
  • an oral glucose tolerance test
  • a hemoglobin A1C test

A fasting test will measure your blood glucose before you eat. The oral test measures your blood sugar before you eat, and then it measures it again after you drink a sugary beverage. The A1C is a simple nonfasting blood test. All are designed to see if the insulin in your body is doing what it should.

That’s important because when you have prediabetes your body produces extra insulin to push blood sugar numbers down, says Weisenberger.

High blood glucose levels, especially if they’re left untreated, can affect other systems in your body. This can leave you vulnerable to a variety of health risks and chronic health conditions. For example, uncontrolled diabetes can lead to vision loss, periodontal disease, kidney damage, or even cardiovascular disease. The high insulin levels that come with insulin resistance can cause additional problems.

If you do have prediabetes, your doctor may even prescribe a medication, such as metformin (Glumetza, Glucophage, Fortamet, Riomet). This can also help increase insulin sensitivity and keep blood glucose levels in check.

The Power of Lifestyle Change

A large, multicenter research study called the Diabetes Prevention Program looked into how lifestyle changes could help prevent diabetes. What they found should give you a lot of hope. With modest weight loss and exercise, study participants reduced their risk of developing diabetes by 58 percent over three years.

The power of healthy food and exercise habits cannot be overstated. Take charge of your health by focusing on simple dietary and lifestyle changes.

Eat Healthier

Focus on whole foods and complex carbohydrates such as beans, grains, and starchy vegetables. Pass on the simple sugars, like those in processed baked goods. Those can raise blood sugar without providing wholesome nutrition.

For help in planning meals to prevent diabetes, make an appointment with a dietitian. The American Diabetes Association also offers great tips on diabetes-friendly cooking.

Move More

Aim for 150 minutes of exercise each week. Any activity is better than nothing. Even walking counts.

Lose Weight

If you are overweight, losing weight can help reduce your risk. A healthier diet and increasing your activity level should help you achieve this goal. Even losing 5 to 10 percent of your body weight will help reduce your risk for diabetes.

Buy A Glucose Monitor

Some people find it helpful to check their glucose levels at home. It can help show how certain foods affect blood sugar more than others. It’s even a motivating factor for some people. If you’ve been diagnosed with prediabetes, your insurance plan may even cover it.

Start Today

Start any diet and lifestyle changes today. It’ll give you the best chance of preventing diabetes in the first place while also avoiding any potential complications from uncontrolled diabetes.

While finding out this early diagnosis can be upsetting, it does not have to mean you will develop diabetes, says Dr. Kristine Arthur, an internist at Orange Coast Memorial Medical Center in Fountain Valley, California.

“It can be reversed and you can stop the progression to diabetes,” she says.