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What is Prediabetes?

Marina Turea
14 minutes
September 2, 2020
September 16, 2020

What is Prediabetes

Prediabetes is characterized by elevated blood sugar. Patients’ blood sugar may be higher than normal, yet not high enough to meet the standard of Type 2 Diabetes.

Prediabetes is sometimes referred to as “impaired fasting glucose” (IFG) or “impaired glucose tolerance” (IGT).

Every year, 200,000 Americans receive a tough diagnosis of Type 2 Diabetes (T2D).

This condition used to be known as “Adult-Onset Diabetes” to distinguish it from the related disease Type 1 Diabetes, a pancreatic autoimmune disorder some children already have at birth. “Adult-Onset Diabetes” is now a misnomer, since the deteriorating quality of the American diet has led to an epidemic of T2D diagnoses among minors too.

In normal bodies, the pancreas produces insulin, a hormone that helps transfer the simple sugar glucose from the red blood cells to muscles, liver, and fat cells. Those cells can then process glucose as energy.

The various forms of diabetes cause the body to become insulin-resistant or insulin-impaired, either by not producing insulin or failing to use it effectively. As a result, glucose never makes it to the cells that need it, leaving it trapped and not utilized in the blood. As the body becomes insulin-resistant, patients experience elevated blood sugar and an increased risk of heart disease, stroke, blindness, and kidney failure.

A diagnosis of Type 2 Diabetes correlates with an average loss of ten years of the patient’s lifespan.

Less well-known, however, is the matter of some 84 million American adults who are prediabetic. According to the CDC, 90% of people living with this condition don’t even know they have it, or that it represents an urgent window of opportunity to avert Type 2 Diabetes.

Patients with prediabetes exhibit early symptoms of insufficient insulin use within the body. As a result, blood glucose levels begin to rise.

Prediabetes is a significant risk factor for the development of T2D. Whether these prediabetics know they have it or not, most patients diagnosed with T2D do present with prediabetes first.

The CDC study revealed a higher prevalence of prediabetes in males vs. females. In a study of 5,800 patients:

  • 22.5% of adolescent boys had prediabetes, compared to 13.4% of adolescent girls
  • 29.1% of young adult males had prediabetes, compared to 8.8% of young adult females.

Prediabetes Risk Factors and Causes

Despite its stealthy nature, prediabetes has a number of well-known risk factors.

Obese or overweight people are likely to be prediabetic, especially people with pronounced belly fat. Excess fat cells make the body more resistant to insulin. A waist measurement over 40” in a man, or 35” in a woman, correlates strongly with prediabetes, as does a body mass index (BMI) over 25.

A history of gestational diabetes is another risk factor. This type of diabetes occurs in pregnant women when pregnancy changes in the body impede insulin uptake and result in high blood sugar. Gestational diabetes can also affect the baby’s health.

Other risk factors include:

  • Having given birth to a baby over nine pounds in birth weight
  • A lifestyle including little or no exercise
  • Latino, Native American, African American, or Pacific Islander heritage
  • Aged 45 or older
  • High LDL cholesterol
  • Low HDL cholesterol
  • High triglycerides
  • A diet high in sugars, sugary drinks, red meat and/or processed meats
  • A diet low in whole grains, vegetables, fruits, nuts, and unsaturated fats
  • Sleep apnea or other sleep disorders
  • Constant or occasional night shifts

You should definitely get tested for prediabetes if you:

  • Have heart disease
  • Exhibit abnormal blood sugar readings
  • Exhibit signs of insulin resistance

How to Screen for Prediabetes

Prediabetes can be detected by a blood test. Indicators of prediabetes revealed by examining the blood include:

Elevated Hemoglobin A1c

Also known as Glycated Hemoglobin or HbA1c. Hemoglobins are proteins found in the red blood cells that carry iron. A1c is specifically linked to sugars.

  • A blood percentage of 4%-5.6% HbA1c is considered normal.
  • A blood percentage of 6.5% HbA1c have diabetes.
  • A blood percentage of 5.7%-6.4% HbA1c could be considered prediabetic.

HbA1c is quick to test for and requires no fasting before lab appointments.

Elevated Fasting Plasma Glucose Levels

When we talk about “high blood sugar,” we mean the simple sugar glucose and its prevalence in the plasma, the liquid component of blood in which blood cells are suspended.

  • Healthy fasting plasma glucose (FPG) levels will fall below 100 mg/dL.
  • FPG above 126 mg/dL indicates diabetes.
  • Any FPG result between 100 and 126 mg/dL does not meet the clinical definition of diabetes but could indicate prediabetes.

As the name indicates, this lab test requires patients to fast before their lab appointment.

Glucose Tolerance Tests

An FPG screening may be paired with a glucose tolerance test to determine if the patient is impaired in his/her ability to absorb glucose.

The most common test is the two-hour 75-gram oral glucose tolerance test (OGTT).

After the fasting blood sample is obtained, the patient is then instructed to drink a solution consisting of 75 grams of glucose dissolved in water. Two hours after drinking the glucose solution, another blood sample is taken.

  • If, after two hours, FPG has risen to a range below 140 mg/dL, this indicates a normal uptake of glucose.
  • If FPG has risen above 200 mg/dL, this level is consistent with a diagnosis of diabetes.
  • An FPG range between 140 and 200 mg/dL after the OGTT indicates prediabetes —an impairment of glucose uptake, but not severe enough to diagnose diabetes yet.

At-Home Blood Tests For Prediabetes

Medicine has adapted to the digital age to bring health screening tools directly into the hands of consumers. This includes home blood screening options like imaware™. The imaware™ home screening kit for prediabetes allows patients to collect their own blood samples quickly, safely, and painlessly.

They then submit the samples to confidential labs and receive results by a secure online portal in as few as seven days. As of its January 6 relaunch, imaware™ allows patients to check their HbA1c and FPG levels and discover if they fall within prediabetic ranges, without making a clinic or lab appointment.

What are the Symptoms of Prediabetes?

Prediabetes goes undiagnosed so often because it has few to no obvious symptoms—at least, nothing to cause immediate alarm.

If checked, patients might present with:

  • Higher-than-normal systolic blood pressure
  • Higher-than-normal non-HDL cholesterol
  • Low insulin sensitivity or glucose tolerance.

All of these internal indicators might go completely unnoticed if not tested for.

Particularly sensitive individuals might notice:

  • Excessive thirst
  • Excessive urination
  • Blurry vision
  • Fatigue
  • Difficulty healing from cuts or sores

Associated Conditions with Diabetes

Associated conditions might indicate prediabetic status, even if the ensuing symptoms are related to the associated condition and not to prediabetes. Examples include:

Acanthosis Nigricans

This associated condition manifests as dark, velvety patches of skin, typically grouped around the elbows, knees, armpits, knuckles, and neck. Acanthosis nigricans is associated with insulin resistance.

Polycystic Ovarian Syndrome

Another condition associated with insulin resistance, polycystic ovarian syndrome (PCOS) affects post-pubescent women characterized by an excess of the male hormone androgen and enlarged ovaries surrounded by follicles. These follicles inhibit the release of eggs.

PCOS is also characterized by long menstrual cycles with infrequent periods—as few as nine a year or one every 35 days. Unexpected acne breakouts can be a useful aid to considering PCOS in women who normally have no menstrual cycle due to being fitted with a coil, or because of taking other contraceptives that interfere with menstruation. While acne can appear for many reasons, if a patient has never had it before and it suddenly shows up, especially in later life, it’s worth discussing PCOS (and the possibility of prediabetes) with a doctor.

What are the Prediabetes Blood Sugar Numbers?

Prediabetes is characterized by the following blood sugar metrics:

  • Fasting plasma glucose (FPG) between 100 and 125 mg/dL.
  • After a 75mg 2-Hour Oral Glucose Tolerance Test, FPG levels of between 140 and 200 mg/dL.
  • Glycated hemoglobin (hemoglobin A1c or HbA1c) between 5.7% and 6.4%. Note that pregnant women or persons with a hemoglobin variant may return inaccurate results on an HbA1c test.

These ranges apply to both adults and children.

How to Reverse Prediabetes

Not everyone who meets the definition of prediabetes will progress to Type 2 Diabetes. However, many patients diagnosed with T2D have probably been prediabetic for years without even knowing it. It is a strong correlative and significant risk factor.

Prediabetic blood sugar and hemoglobin test results should serve as a call to arms. Patients have a rare opportunity to reverse this damaging course and protect themselves from a debilitating, extremely life-shortening condition that brings a plethora of complications.

Many prediabetics are overweight or obese. A reduction of body weight by 5%-7% (usually losing 10-20 pounds) strongly correlates with a reversal of prediabetic blood sugar levels.

The best way to reverse prediabetes is to adopt a healthy lifestyle, including:


Building more physical activity into your daily routine can contribute significantly to the reversal of prediabetes. Physical activity lowers blood glucose levels and reduces body weight.

Thirty minutes of exercise a day, five days a week, is a proactive approach to reversing prediabetes. If this is too much right off the bat, consider starting slowly and building up exercise as a habit before increasing the intensity. Activities to consider include jogging, walking, swimming, cycling, weight training, and yoga. Make sure to check with your doctor before commencing an exercise routine.

Healthy Food Choices

Prediabetics don’t necessarily need to eat less food if they can transition to higher-quality foods.

  • Someone with prediabetes can eat as much as they like of non-starchy vegetables like carrots, broccoli, green beans, spinach, and other leafy greens, or at least three servings per day.
  • Fruit, on the other hand, contains a lot of sugar, and prediabetics do not need more. Try to limit servings of fruit to between one and three. Fruit can be an appropriate substitute for high-fat or high-sugar snacks like chips or candy, however, as long as intake is limited. Other good snack choices include seeds, nuts, and whole-grain crackers.
  • Substitute enriched, bleached, or processed grains (white bread, white rice, etc.,) with whole grains, sprouted grains, and brown rice.
  • Vegetables, fruits, and whole grains are excellent sources of fiber, helping to balance the appetite and control cravings for high-calorie, high-fat foods.
  • Limit the amount of red or fatty meats, while emphasizing lean meats like chicken, or meats rich in good fatty acids such as fish or other seafood.
  • Avoid fatty milk and cheeses. Skimmed milk and low-fat cheeses are acceptable.
  • Avoid sugary drinks like soda, fruit juices, sweetened coffee or tea, or sugary sports drinks like Gatorade as much as possible.

Not every food recommendation is appropriate for every person, as body chemistry is quite individual. Consider consulting a nutritionist for more personalized recommendations.


Lack of sleep makes it nearly impossible to lose weight. When the body loses sleep, it responds with overproduction of the hormones leptin and ghrelin. These hormones make you hungry.

Losing sleep also reduces your body’s ability to use insulin effectively, resulting in elevated blood sugar. It can be a vicious cycle, too, because excessive body weight also puts you at risk of sleep disorders like insomnia and sleep apnea.

Certain behavioral habits can help normalize the sleep cycle, even for overweight persons. These habits include:

  • Setting a schedule. Go to bed and wake up at the same time every day to establish a stable circadian rhythm (24-hour physiological cycle)
  • Relaxing before bed. Try lying down and reading an hour before bedtime
  • Avoid caffeine after lunchtime. If you consume caffeinated coffee, tea, or other products, restrict consumption to the morning
  • Turning off all screens. Don’t watch TV, look at your smartphone, or look at your computer screen a full hour before bedtime
  • Sleep in a darkened room. Make sure no lights are on in your sleeping room, including indicator lights on devices. Consider blackout blinds if you live on a lighted street
  • Set the proper temperature for your sleeping room. Between 60 and 67 degrees Fahrenheit is optimal for the sleep cycle. Let in some fresh air if you tend to sleep restlessly in a warmer room.

Other Resources

Many diabetes-prevention resources, both in-person and online, could help patients with prediabetes. The Center for Disease Control (CDC) operates the National Diabetes Prevention Program (NDPP) throughout the US, offering year-long, in-person lifestyle change programs. DPS Health, Noom Health, and Omanda Health also offer year-long lifestyle change programs via their industry-leading online platforms.

Prediabetics should make regular doctor visits, every three to six months at least, to track their progress.


The anti-diabetic medication metformin (trade names Glucophage, Glucophage XR, Glumetza) may help prediabetics achieve normal blood sugar numbers, the same as it does for diabetics.

It does this by increasing muscle cells’ sensitivity to insulin and reducing the amount of sugar produced by the liver.

Metformin is available by prescription only and must be taken as directed by your doctor. Patients taking metformin should not drink alcohol.

What to Do if You Think You Have Prediabetes

If you suspect that you may be prediabetic, take immediate steps to safeguard your health. Type 2 Diabetes is a serious condition, and prediabetes a priceless window of opportunity to nip it in the bud.

1. Verify—take the imaware™ test

As of January 6, 2019, imaware™ offers do-it-yourself home blood testing kits that screen for prediabetes indicators, including Hemoglobin A1c and fasting plasma glucose levels.

You can submit your test confidentially to a lab and receive your results by a secure online portal in as few as seven days. It’s the easiest, most affordable, and most convenient way to confirm if your blood sugar metrics rise to prediabetic levels.

2. Be proactive—make lifestyle changes

Don’t wait for a diagnosis of diabetes or prediabetes to make changes. As of 2019, 76% of Americans do not get enough exercise. Most Americans also eat too much sugar, fat, and sodium, while eating too few vegetables, fruits, and unsaturated fats.

Take steps now to join the minority with healthy habits. Add exercise, a healthy sleep cycle, and healthy eating choices to your routine. Become educated about the science of fitness, nutrition, and weight loss. Remember, a reduction of 5-7% pounds of body weight often correlates with a reversal of prediabetes. If you’re unsure how to calculate it, take your total body weight and divide it into 20, for the minimum desired loss to aim for. Especially keep an eye on dangerous excess abdominal fat.

Make a meal plan and an exercise plan. Feel free to start slow—a light walk every other day, or cutting out sugary beverages. If you try to do too much exercise too soon or completely overhaul your diet, you run the risk of burning yourself out. Focus instead on the gradual adoption of manageable, sustainable habits.

If necessary, consult a personal trainer, nutritionist, or sleep specialist.

3. Seek support.

Find out if the National Diabetes Prevention Program (NDPP) has offices near you. If so, stop by. Seek out diabetes support groups, in person or online. Join lifestyle groups like running clubs or fitness groups that align with your lifestyle goals.

Share your concerns with friends, family, colleagues, or therapists if you think it is appropriate. Rally them to your cause and stress the importance of them ceasing to encourage your unhealthier eating and drinking habits. This is about avoiding a serious health problem, so if everyone is on board, you’ll get there easier. A strong support group is invaluable in the face of a health challenge.


Prediabetes is both a warning sign and an opportunity. Most people who get diagnosed with Type 2 Diabetes were initially prediabetic, possibly for years, without ever knowing it.

Discovering you are prediabetic is a cloud with a silver lining—you have an opportunity to make healthy decisions that avoid Type 2 Diabetes with its gamut of severe symptoms and very bleak prognosis.

Prediabetes is characterized by elevated blood sugar metrics like Hemoglobin A1c and fasting plasma glucose levels. These levels are higher than normal, but not high enough to indicate a diagnosis of diabetes.

They do, however, indicate abnormalities in your body’s ability to process insulin, a precursor for Type 2 Diabetes.

Risk factors for prediabetes include:

  • Obesity or excess body weight, particularly an excess of belly fat
  • High LDL cholesterol, low HDL cholesterol
  • High triglycerides
  • Unhealthy habits like lack of exercise or excess calories in the diet
  • Disrupted sleep cycle by night shift work or sleep apnea
  • African American, Native American, Latin, or Pacific Islander heritage.

Prediabetes typically carries no symptoms, though observant patients may notice thirst, frequent urination, fatigue, or blurry vision.

You can discover if you have prediabetes with blood tests, including:

  • Non-fasting tests for Hemoglobin A1c
  • Fasting plasma glucose screening
  • A possible follow-up plasma glucose screening with a 75mg two-hour oral glucose tolerance test.

Blood screening for prediabetes can be performed at a clinic or lab, or at home using an imaware™ home screening kit.

If you suspect or discover that you have prediabetes, the condition can often be reversed before it progresses to T2D. Steps you can take to reverse prediabetes include:

  • Exercise regularly. Join workout buddies, fitness groups, or hire a personal trainer if necessary.
  • Adopt healthy sleep patterns. Go to bed and wake up at the same time; relax and read before sleeping; avoid screens like your TV, computer or phone before bed; sleep in a darkened room, cooled to 60-67 degrees Fahrenheit and with plenty of fresh air if possible.
  • Adopt a healthy diet. Cut out sugary drinks, limit processed grains, fatty dairy products, and red meats; eat fruits in moderation; add fiber, unsaturated fats, and whole grains to your diet. A loss of 5%-7% of total body weight also goes a long way to alleviating the prediabetic condition. Then be sure to keep it off and especially avoid accruing belly fat.
  • Seek support for prediabetes. Check out the CDC’s National Diabetes Prevention Program (NDPP) or the help of online health platforms.
  • Quit smoking
  • Consider medication. Your doctor may prescribe metformin to help you control your blood sugar levels.

With effort, determination, support, and the right mindset, patients with prediabetes can reverse the course of the disease and lead a healthy, active life.

What Is Prediabetes
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Marina Turea
Content Project Manager

With a Masters in Medical Science, Marina Turea is a professional health writer and content manager based in Chicago. Passionate about emerging tech in healthcare, she writes regularly for healthcare magazines and imaware.