Medically Reviewed on 7/18/2023

What is prediabetes?

Prediabetes is the term used to describe elevated blood sugar (glucose) that has not yet reached the threshold of a type 2 diabetes diagnosis. Consider pre-diabetes a warning sign that it is time to take your health more seriously. Prediabetes typically has no symptoms or signs; however, it has been associated with being overweight. Prediabetes is reversible by getting healthier.

What is the difference between prediabetes and type 2 diabetes?

Prediabetes occurs when there is too much sugar (glucose) in the blood. It is an early warning sign that the body has more sugar in the blood than it can use.

Type 2 diabetes is a condition that occurs slowly over time. The pancreas cannot produce enough insulin to keep up with the increased need to move sugar into the cells for energy. Medication and lifestyle changes are necessary to manage blood sugar levels and avoid diabetes complications.

Type 1 diabetes is different, and results from auto-immune attacks on the pancreas.

What are the signs and symptoms of type 2 diabetes?

Without reversing prediabetes, blood sugar continues to rise and signs and symptoms of diabetes may develop. The most common symptoms and early signs are thirst and excess urination. Sometimes people will notice unexplained weight loss.

Later signs of type 2 diabetes include:

  • Fatigue
  • Blurry vision
  • Slow-healing wounds or bruises
  • Thirst
  • Excess urination
  • Unusual smell to the urine

What causes prediabetes, and what are the risk factors for prediabetes?

Pre-diabetes is a warning sign that metabolism is getting out of balance. Humans are designed to be physically active hunters and gatherers who move a lot and eat only occasionally. This isn't what most of us do. Essentially, the underlying cause of prediabetes is that there is more fuel (glucose) available than can be used up. This can be because of excess intake of dietary carbs and sugars, because of insulin resistance, or because the liver is making too much glucose. The easiest causes of prediabetes to manage are insulin resistance and excess dietary intake. For many people with prediabetes, it can be reversed with exercise in combination with eating a low-carb diet (low-glycemic index diet).

Some of the risk factors for prediabetes include:


Diabetes is defined best as... See Answer

What are the signs and symptoms of prediabetes?

Unfortunately, there are no symptoms or signs of prediabetes. It almost always is diagnosed by chance during a medical screening or routine bloodwork. This is why it is important to get screened, especially if you are overweight or have family members with diabetes or pre-diabetes. However, the most common sign associated with prediabetes is being overweight.

It is common for a person with prediabetes to only have slightly elevated blood sugar levels, but the body continues to require increased insulin to maintain it. Hyperinsulinemia or high insulin, has signs and symptoms of the following:

  • Sleepiness (after a meal)
  • Lethargy
  • Weight gain around the abdomen

Occasionally, people may notice they are thirstier than normal or are urinating more frequently.

What kind of doctors diagnose and treat prediabetes?

Prediabetes is typically diagnosed and managed by your primary care practitioner, including internists and family medicine specialists, or pediatricians in the case of children or adolescents. Other specialists who may be consulted include physicians who specialize in endocrine glands and hormones including diabetes management (Endocrinologists). A nutritionist can be consulted to help you review your diet and suggest dietary and lifestyle changes. A personal trainer can be helpful if you are having a hard time putting together an exercise plan for yourself. There are a lot of self-care resources too. Eating healthier, exercising, and losing weight are ways to improve your health, and are key to prediabetes treatment.

Is there a test to diagnose prediabetes (HbA1c and prediabetes chart)?

There are three blood tests that can diagnose prediabetes and type 2 diabetes.

Hemoglobin A1c (HbA1c)

  • Hemoglobin A1c (HbA1c) measures the average blood sugar (glucose) over the last 3 months. It is a measure of how much sugar is attached to your red blood cells.
  • A pre-diabetes level is 5.7% and 6.4%.
  • An HbA1c > 6.5% is considered a diabetes glucose level.

Fasting blood sugar levels (serum glucose)

  • Fasting blood sugar or serum glucose is a measure of your blood sugar first thing in the morning before you have eaten anything.
  • Prediabetes also can be identified with serum glucose or blood sugar level. A fasting blood sugar test of 100-125 mg/dl indicates prediabetes.

Oral glucose tolerance test

Prediabetes glucose levels are shown here in a chart of normal, prediabetes, and diabetes lab test numbers so you can make comparisons.

Prediabetes Chart
Normal Prediabetes Diabetes
HbA1c 5.6% or less 5.7%-6.4% 6.5% or more
Fasting blood glucose 99mg/dl or less 100-125mg/dl 126mg/dl or more
Oral glucose tolerance 140mg/dl or less 140-199mg/dl 200mg/dl or more

What is the treatment for prediabetes?

Prediabetes is best treated with a proactive, renewed commitment to getting healthier and making healthier choices every day. It can, and usually is, be treated with diet and exercise alone. However, some people with prediabetes are treated with a medication called metformin (Glucophage, Glucophage XR, Glumetza, Fortamet, Riomet). Research published in the New England Journal of Medicine showed that lifestyle changes reduced diabetes incidence by 58% compared to metformin, which reduced the incidence by only 31%.1

If you have been diagnosed with prediabetes, discuss a treatment plan with your healthcare professional.

What medications or supplements treat prediabetes?

Metformin is the only medication approved by the FDA to treat prediabetes. It works by stopping the liver from producing excess glucose. For some people, metformin also helps them lose weight. It can be an option for people who aren't ready or able to make lifestyle changes right away. Metformin also is a medication that can be discontinued as soon as blood sugar levels are at goal, and healthy lifestyle habits have become routine.

Some dietary supplements have good evidence of helping reverse prediabetes. For example, most people with prediabetes are deficient in vitamin D and magnesium. Both of these are necessary to keep cells properly sensitive to insulin. A healthcare professional can order a blood test to check and see if you're deficient in these and other nutrients, for example, chromium, biotin, and N-acetyl cysteine. These also are nutrients that have research supporting their role in improving insulin sensitivity.3 Check with a healthcare professional before taking supplements. You may need to find one with this specialized knowledge such as a naturopathic doctor, nutritionist, or integrative medicine doctor.

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What about a low carb diet for prediabetes?

A low-carb diet is a great option for prediabetes because it will improve blood sugar, help you lose weight, and help you feel more energetic. Carbohydrates are digested into glucose very easily. A person with prediabetes already has too much sugar in the blood so you don’t want to add any more.

To feel satisfied on a low-carb diet you have to eat healthy amounts of protein and fat. Many people continue to try to follow a low-fat or fat-free diet while also trying to make low-carb choices, and understandably, feel hungry and frustrated because there is nothing tasty to eat. Recent research published in the British Medical Journal debunked the low-fat hypothesis (that people on a low-fat diet have a lower risk of developing prediabetes).2 People are not at a lower risk of prediabetes.

What is the glycemic index?

The easiest way to choose quality carbohydrates is by following a low glycemic index diet. With a low glycemic index diet, you balance the carbohydrate/sugar content of a meal with enough fiber, fat, and protein so that the meal is digested and absorbed slowly. This gradually releases glucose into the bloodstream, and thus the body does not require a large amount of insulin. It also provides the body with good, steady energy over many hours.

Is there prediabetes diet?

The best foods for prediabetes include the following:

  • healthy proteins and fats
  • Lots of vegetables
  • Some fruits
  • Some low glycemic index carbohydrates like quinoa, oatmeal, and brown rice

The foods to eat for prediabetes are real foods in their natural or whole form. There needs to be a balance of fat, protein, and carbohydrate. Drinking lots of water or unsweetened tea also is important.

Food to Avoid for Prediabetes Management

An easy way to identify the most important foods to avoid is to avoid any white food, which includes:

  • Sugar (and anything made with sugar)
  • White flour (and anything made with flour)
  • White bread
  • White rice
  • White pasta
  • White potato, etc.

Cauliflower is white, but it is a good food for prediabetes because it is a whole, real vegetable.

It also is best to avoid highly processed foods (like foods that come in boxes or packages already prepared). These foods are high in calories, carbs, and chemicals, and low in nutrients and vitamins. Other foods to avoid include:

  • Fried foods
  • Fatty meat such as prime rib, burgers, bacon, and fatty cuts of pork, sausages, greasy burgers, hydrogenated fats.
  • Blackened or burned foods (these cause inflammation)
  • Snack foods like pretzels, chips, or cookies
  • Many “energy bars” (compare nutrition labels - a bar that is friendly for prediabetes will have less than 5 grams of sugars and at least 2 grams of fiber)
  • Meals without any vegetables
  • Sodas, sweetened tea, fruit juice, juice-like sweetened beverages

The take-home message is to pay close attention to the quality of all foods - fats, proteins, and carbohydrates – and choose less processed ones.

What are examples of good food choices for a prediabetes diet?

Choosing quality fats and proteins means choosing real food rather than processed versions. Believe it or not, a serving of organic full-fat Greek yogurt with real raspberries will be much more satisfying, and better for your blood sugar and weight, than the fat-free fruity version.

Good protein choices include:

  • Organic poultry (chicken or turkey)
  • Grass-fed red meat (beef or buffalo)
  • Organic lean pork
  • Wild fish and seafood
  • Whole eggs
  • Plant-based proteins such as:
    • Beans
    • Lentils
    • Nuts
    • Seeds
    • Tofu
    • Peas
    • Protein powders for smoothies

Organic and grass-fed choices are important because what an animal eats changes the nutrition of the meat. Non-organic and factory-fed animal meats increase inflammation. In prediabetes, this means an increased risk for heart disease and complications.

Make at least some of your meals vegetarian because plant-based fats are associated with lower oxidized LDL and less inflammation. Good fat choices include:

  • Avocado
  • Olive oil
  • Coconut oil and coconut milk
  • Organic full-fat dairy products
  • Wild, cold water fish
  • Grass-fed red meat
  • Dark meat from pastured poultry

Check labels because hydrogenated fats are often used in packaged bakery products.

What about exercise and prediabetes?

All exercise helps reverse prediabetes by using up sugar in the bloodstream and improving insulin sensitivity. An exercise plan should focus on two things:

  1. Be physically active every day. This could be a walk after dinner, doing yard work or gardening, playing with the kids, swimming, biking, dancing, etc. Tracking the number of steps you take each day with a smartphone or fitness tracker can be very helpful.
  2. Focus on building more muscle a few times a week.

Increasing muscle strength makes the cells of the muscle "hungrier (more insulin sensitive), and that equals a healthier metabolism. You can build muscle by using weights, your body weight, or resistance bands. If you choose weight training start slowly, and ask for help using the equipment safely and properly. Begin with low weights, and gradually work up to heavier weights. Lifting one round of heavy weights for only 6-8 repetitions has more benefit than one round of light weights for 10 or more repetitions. If you can do more than 10 repetitions, add more weight.

This plan also is great if you are in a hurry. You can complete a full workout in just 20 minutes twice a week. Work up to this gradually to avoid injury.

If you like cardiovascular exercise, focus on short bursts of high-intensity activity. Research studies show that few people lose weight by spending an hour on a treadmill or elliptical machine. Lifting heavy weights, and short sprints that make you breathless helps you lose weight best. For most people, this is less than 90 seconds, after which, you should walk until you catch your breath and do it again! You'll be done in 20 minutes.

And, as always check with your health-care professional before starting any exercise program and get help using equipment properly to avoid injury.

What is the prognosis for a person with prediabetes?

Unfortunately, most Americans with prediabetes don't make healthy changes or aren't empowered to take control of their health. Because of this, most people with prediabetes do progress to diabetes. But the good news is, and what research proves, is that with physical activity and healthier foods 58% of new cases of diabetes can be prevented.

Can prediabetes be reversed?

Prediabetes can be reversed with lifestyle changes. This includes being more physically active and following a healthy diet plan such as a low glycemic index diet, rich in quality, real foods. Quitting smoking, stress management, and keeping alcohol intake moderate all help too. If lifestyle is not changed, prediabetes usually progresses to diabetes.

How do I monitor my efforts to reverse prediabetes?

When you are working to reverse prediabetes, your healthcare professional will advise you on how often you should have your blood tests checked – usually every 3 months.

Having your home glucose monitor (finger stick test) gets you involved in managing your prediabetes, and also can help you track your progress. Write down the numbers and what was consumed to learn how you respond to different meals. This is a great way to test different prediabetes meal plans to find out what foods cause your blood sugar levels to go up the least, and the most!

Do the following to track your meals and foods.

  • Check your blood sugar and write it down.
  • Enjoy your meal and write down what you ate and the portion sizes.
  • In two hours, check your blood sugar and write it down. Did that meal treat your body well? How much did your blood sugar go up? How did you feel?
  • Keep a log of these readings to discuss them with your healthcare professional or nutritionist to problem-solve ways to make better diet choices. This will help you find foods to eat and foods to avoid for your situation.

Can prediabetes be prevented?

Absolutely! The best way to prevent prediabetes includes the following:

  • Stay active
  • Eat a healthy low glycemic index diet
  • Handle stress in healthy ways

If you had gestational diabetes, you may want to pay special attention to adopting the habits discussed in this article.

Most importantly, for people with prediabetes, diabetes can be prevented by taking action now.

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Medically Reviewed on 7/18/2023
1. Diabetes Prevention Program Research Group. "Reduction in the Incidence of Type 2 Diabetes with Lifestyle Intervention or Metformin." N Engl J Med 2002; 346:393-403.

2. Ramsden, C. E. et al., "Re-evaluation of the traditional diet-heart hypothesis: analysis of recovered data from Minnesota Coronary Experiment (1968-73)." BMJ 2016;353:i1246.

3. Mwiti, K. C., et al. "The Biochemical Role of Macro and Micro-Minerals in the Management of Diabetes Mellitus and its Associated Complications: A Review." Int J Vitam Nutr Res. 2015;85(1-2):88-103.