- Prediabetes is defined by an A1C of 5.7-6.4%, a fasting glucose of 100-125 mg/dL, or a 2-hour glucose of 140-199 mg/dL — higher than normal but below the diabetes threshold.
- An estimated 98 million U.S. adults (more than 1 in 3) have prediabetes, and roughly 8 in 10 do not know it because it usually causes no symptoms — which is why screening matters.
- Major guidelines recommend screening adults starting at age 35, and earlier for those who are overweight or have other risk factors; a repeat or second test confirms the diagnosis.
- Prediabetes is often reversible: in the landmark Diabetes Prevention Program, modest weight loss plus regular activity cut the risk of progressing to type 2 diabetes by 58% (71% in adults 60+).
- Metformin and, increasingly, GLP-1-based medicines are options for some higher-risk people, but they are clinician-directed and do not replace lifestyle change; there is no self-dosing here.
- Prediabetes also raises cardiovascular risk, so a good plan addresses blood pressure, cholesterol, and blood sugar together — not glucose alone.
An estimated 98 million American adults — more than one in three — have prediabetes, and roughly 8 in 10 of them do not know it, according to the most recent estimates from the CDC. Prediabetes means your blood sugar is higher than normal but not yet high enough to be classified as type 2 diabetes. It is best understood as a warning period and a window of opportunity: the right changes during this stage can often return blood sugar to normal and head off a lifelong chronic disease. Left unaddressed, prediabetes raises the risk of type 2 diabetes, heart disease, and stroke. This guide walks through testing, what your results mean, and the steps with the strongest evidence behind them. For more on serious health conditions, visit our medical conditions guide. This article is general education, not medical advice.
Prediabetes is diagnosed by an A1C of 5.7–6.4%, a fasting glucose of 100–125 mg/dL, or a 2-hour glucose of 140–199 mg/dL. It usually has no symptoms, so screening — generally starting at age 35, earlier with risk factors — is how most people find out. It is frequently reversible with modest weight loss and regular activity, and some people also benefit from clinician-directed medication. Diagnosis and any medication decisions belong with a licensed clinician; this article does not provide dosing.
What Prediabetes Actually Means
Prediabetes is a metabolic state characterized by impaired glucose regulation. In a healthy body, the pancreas produces insulin, which helps cells absorb glucose from the bloodstream for energy. In prediabetes, cells become less responsive to insulin — a condition called insulin resistance — and the pancreas must work harder to keep blood sugar in check. Over time the pancreas cannot keep up, and blood sugar levels drift above the normal range.
There are two recognized subtypes of prediabetes: impaired fasting glucose (IFG) and impaired glucose tolerance (IGT). IFG refers to elevated blood sugar after an overnight fast, while IGT refers to elevated blood sugar after consuming glucose (typically measured with an oral glucose tolerance test). Some people have both. Research published in Diabetes Care suggests that IGT may carry a somewhat higher risk of progression to diabetes than IFG alone.
Prediabetes is not a benign condition. Even before blood sugar reaches the diabetic threshold, elevated glucose and insulin resistance are already doing damage. People with prediabetes have an increased risk of cardiovascular disease, nerve damage, kidney dysfunction, and fatty liver disease. The encouraging news is that prediabetes is highly modifiable — large trials show that lifestyle change can reduce the risk of progressing to diabetes by more than half.
How to Know If You Have Prediabetes
Prediabetes rarely produces noticeable symptoms, which is why testing is essential rather than waiting to “feel” it. The U.S. Preventive Services Task Force recommends screening for prediabetes and type 2 diabetes in adults aged 35 to 70 who are overweight or obese. The American Diabetes Association, in its annually updated Standards of Care, recommends considering screening for all adults starting at age 35 — and earlier for people with risk factors such as a high BMI, a family history of diabetes, or a history of gestational diabetes. Because guidelines are reviewed and refreshed periodically, confirm the current thresholds with your clinician.
Three tests are used to identify prediabetes:
- Fasting plasma glucose (FPG): A blood sugar level of 100–125 mg/dL after an overnight fast indicates prediabetes. Normal is below 100 mg/dL, and 126 mg/dL or above on two separate tests indicates diabetes.
- Hemoglobin A1C: This test reflects average blood sugar over the past two to three months. An A1C of 5.7–6.4% indicates prediabetes. Normal is below 5.7%, and 6.5% or above indicates diabetes.
- Oral glucose tolerance test (OGTT): Blood sugar is measured two hours after drinking a 75-gram glucose solution. A level of 140–199 mg/dL indicates prediabetes. Below 140 is normal, and 200 or above indicates diabetes.
If one test comes back in the prediabetic range, your clinician will typically repeat it or order a different test to confirm. Discordant results are common — you might have a normal fasting glucose but an elevated A1C, for example. Each test measures a slightly different aspect of glucose metabolism, which is why the full picture matters. A1C can also be misleading in certain conditions (such as some anemias, recent blood loss, or certain hemoglobin variants), so your clinician may lean on a fasting glucose or OGTT if your A1C seems unreliable.
Prediabetes itself is silent, but symptoms that suggest blood sugar has climbed into the diabetic range — excessive thirst, frequent urination, blurred vision, unexplained weight loss, or unusual fatigue — deserve prompt medical evaluation. Seek emergency care (call 911 in the U.S.) for signs of a diabetic emergency such as confusion, vomiting that won’t stop, rapid or labored breathing, fruity-smelling breath, or fainting. These can signal dangerously high blood sugar and should never be “watched at home.”
Risk Factors You Should Know
Weight is the strongest modifiable risk factor for prediabetes. Excess body fat — particularly visceral fat stored around the abdomen — directly contributes to insulin resistance. A waist circumference above 40 inches in men or 35 inches in women is an independent risk factor, even in people whose overall body mass index is not dramatically elevated.
Physical inactivity compounds the problem. Muscle tissue is the primary consumer of blood glucose, and regular physical activity increases insulin sensitivity. A sedentary lifestyle, by contrast, allows insulin resistance to develop and worsen. The National Institute of Diabetes and Digestive and Kidney Diseases identifies inactivity as one of the leading contributors to the prediabetes epidemic.
Family history is significant — having a parent or sibling with type 2 diabetes roughly doubles your risk. Certain groups, including African Americans, Hispanic/Latino Americans, American Indians, Pacific Islanders, and some Asian Americans, face higher risk. Women who had gestational diabetes have roughly a 50% chance of developing type 2 diabetes within 5 to 10 years after pregnancy. Polycystic ovary syndrome (PCOS), obstructive sleep apnea, and a history of cardiovascular disease are also associated with increased prediabetes risk.
The Landmark Diabetes Prevention Program
The single most influential study in prediabetes management is the Diabetes Prevention Program (DPP), a large randomized controlled trial funded by the National Institutes of Health. The DPP enrolled more than 3,200 participants with prediabetes and compared three approaches: intensive lifestyle modification, metformin, and placebo.
The results were striking. Participants in the lifestyle intervention group — who aimed for 7% weight loss and 150 minutes of moderate physical activity per week — reduced their risk of developing type 2 diabetes by 58% compared with placebo. Metformin reduced risk by 31%. Among participants aged 60 and older, the lifestyle intervention was even more effective, reducing risk by 71%.
Long-term follow-up over 15 to 22 years has confirmed that the benefits of the lifestyle intervention persist, even as some participants regain weight. The DPP results led to the CDC-recognized National Diabetes Prevention Program (National DPP), a structured lifestyle-change program available throughout the United States, both in person and online. Many insurance plans — and Medicare, through the Medicare Diabetes Prevention Program — cover these programs for eligible people, which is worth exploring if cost is a concern, as discussed in our healthcare costs guide.
Lifestyle Changes That Work
The lifestyle changes that reverse prediabetes are simple in concept, though they require sustained effort. Modest weight loss — about 5 to 7% of body weight, or roughly 10 to 14 pounds for a 200-pound person — is enough to produce clinically meaningful improvements in insulin sensitivity. You do not need to reach an “ideal” weight; even small reductions in body fat, especially abdominal fat, deliver a disproportionately large metabolic benefit.
Physical activity is equally important and works independently of weight loss. The commonly recommended target is at least 150 minutes per week of moderate-intensity activity, such as brisk walking, cycling, or swimming. Resistance training (strength exercise at least twice per week) adds benefit by building muscle mass, which increases glucose uptake. Research indexed in PubMed has shown that combining aerobic and resistance exercise is more effective than either alone. Reducing prolonged sitting — standing up and moving for a few minutes every half hour or so — also helps blood sugar control.
Dietary changes should focus on overall patterns rather than single foods. Diets rich in vegetables, fruits, whole grains, lean proteins, and healthy fats — such as the Mediterranean or DASH patterns — have consistently shown benefits for blood sugar control. Cutting back on refined carbohydrates, sugary beverages, and heavily processed foods helps stabilize blood sugar and reduce excess calories. You do not need a rigid or extreme diet; sustainable, moderate changes produce the best long-term results.
Sleep and stress matter too. Poor or insufficient sleep (fewer than about six hours per night) impairs glucose metabolism and increases insulin resistance. Chronic stress elevates cortisol, a hormone that raises blood sugar. Addressing these factors through sleep hygiene, stress management, and treatment for conditions like sleep apnea when present can support your metabolic health.
Medication Options
For some people, lifestyle change alone is not enough, or day-to-day adherence is difficult. Metformin has the strongest evidence for diabetes prevention and is suggested by the American Diabetes Association for certain higher-risk individuals — particularly younger adults, those with a substantially elevated BMI, and women with a history of gestational diabetes. It works by reducing the liver’s glucose production and improving insulin sensitivity, is inexpensive, and has a long safety record. The most common side effects are gastrointestinal (nausea, diarrhea, bloating), which often ease over time or with an extended-release formulation. Whether metformin is right for you, and at what dose, is a decision for your clinician; this guide does not provide dosing.
Newer weight-management medicines have also reshaped the conversation. GLP-1 receptor agonists such as semaglutide, and the dual GIP/GLP-1 agonist tirzepatide, produce substantial weight loss, and clinical trials in people with obesity have reported markedly lower rates of progression to type 2 diabetes while participants remain on treatment. As of 2026, however, these drugs are approved for obesity and type 2 diabetes rather than specifically for “preventing diabetes” in prediabetes, their long-term role in prediabetes is still being defined, and access is often limited by cost and insurance coverage. Effects may also diminish if the medication is stopped. Any use of these medicines should be individualized and directed by a clinician, alongside — not instead of — lifestyle change.
Monitoring and Follow-Up
If you have been diagnosed with prediabetes, regular monitoring helps track progress and catch any progression to diabetes early. The American Diabetes Association recommends at least annual testing with fasting glucose, A1C, or OGTT. If you are actively making changes, testing more often — such as every three to six months — can provide motivating feedback and help you and your clinician adjust the plan.
Home blood glucose monitoring is not routinely recommended for prediabetes, but some people find it helpful for understanding how specific foods and activities affect their blood sugar. Continuous glucose monitors (CGMs), once reserved for people with diabetes, are increasingly used by health-conscious individuals for real-time insight into their metabolic responses; a few over-the-counter CGMs are now available, though their value for people without diabetes is still being studied and they are not a substitute for standard testing.
Beyond glucose, your clinician should also assess cardiovascular risk factors. People with prediabetes are at increased risk for heart disease, so blood pressure, cholesterol, and other markers should be evaluated and managed. A comprehensive annual checkup that addresses all of these factors provides the best foundation for long-term health.
Cardiovascular and Other Health Risks
Prediabetes is not just a “pre-diabetes” problem — it is an independent risk factor for cardiovascular disease. The insulin resistance behind prediabetes is closely linked to a cluster of abnormalities known as metabolic syndrome, which includes abdominal obesity, high triglycerides, low HDL cholesterol, high blood pressure, and elevated fasting glucose. According to the American Heart Association, people with metabolic syndrome have roughly twice the risk of cardiovascular events as those without it.
Metabolic dysfunction-associated steatotic liver disease (MASLD) — the condition formerly called non-alcoholic fatty liver disease (NAFLD) — is another common companion of prediabetes, affecting a majority of people with significant insulin resistance. It can progress to inflammation, fibrosis, and cirrhosis. Weight loss and exercise improve it, reinforcing the value of lifestyle change.
Cognitive effects are also emerging in the research. Studies have linked insulin resistance and prediabetes to a higher risk of cognitive decline and Alzheimer’s disease — sometimes informally called “type 3 diabetes” in the scientific literature. While this research is still evolving, it is one more reason to address prediabetes proactively.
Frequently Asked Questions
Can prediabetes be reversed completely?
Often, yes. With sustained lifestyle change — particularly weight loss and regular activity — many people return their blood sugar to the normal range. The Diabetes Prevention Program showed that lifestyle intervention cut diabetes risk by 58%, and long-term follow-up shows that reversal can be durable when healthy habits are maintained. However, the underlying tendency toward insulin resistance remains, so ongoing vigilance and periodic testing are important.
How quickly does prediabetes progress to diabetes?
Without intervention, roughly 15 to 30% of people with prediabetes develop type 2 diabetes within five years. The pace varies with the degree of glucose elevation, the number of risk factors, and whether lifestyle changes are made. Some people stay in the prediabetic range for years, while others progress faster.
Should I avoid all carbohydrates if I have prediabetes?
No. Carbohydrates are part of a balanced diet, and eliminating them entirely is neither necessary nor sustainable. Focus on choosing complex carbohydrates — whole grains, legumes, vegetables, and fruit — over refined and processed carbs like white bread, sugary drinks, and pastries. Portion control and pairing carbohydrates with protein or healthy fat can help minimize blood sugar spikes.
Does prediabetes cause symptoms?
Most people with prediabetes have no noticeable symptoms. Some develop acanthosis nigricans — dark, velvety patches of skin, typically on the neck, armpits, or groin — a sign of insulin resistance. Increased thirst, frequent urination, and fatigue are more typical of diabetes but can occasionally appear. The silent nature of prediabetes is exactly why routine screening matters.
Is treatment for prediabetes covered by insurance?
Many plans, including Medicare, cover the CDC-recognized National Diabetes Prevention Program for eligible people, and coverage for metformin and laboratory tests is common. Coverage for GLP-1 medicines is more variable and often restricted. Check with your insurer about specific details, and explore community-based DPP programs if cost is a barrier.
What A1C means I have prediabetes?
An A1C between 5.7% and 6.4% is in the prediabetes range. Below 5.7% is considered normal, and 6.5% or higher on repeat testing indicates diabetes. Because a single result can be affected by other conditions, clinicians usually confirm with a repeat A1C or a fasting glucose before making the diagnosis.
What to Do Next
If you have not been tested and you are over 35, overweight, or have any of the risk factors above, ask your clinician about a screening test. If you already have a prediabetes diagnosis, take it seriously — it is your body giving you advance notice that something needs to change while there is still time to change it.
Start with achievable goals: walk 30 minutes a day most days of the week, cut sugary drinks, and aim to lose 5 to 7% of your body weight. Enroll in a Diabetes Prevention Program if one is available near you or online. These steps are backed by some of the strongest clinical evidence in all of medicine. Prediabetes is a diagnosis with a built-in escape route — and the sooner you act, the wider that route stays open.
Sources
- Centers for Disease Control and Prevention (CDC) — Prediabetes; National Diabetes Statistics Report
- U.S. Preventive Services Task Force (USPSTF) — Screening for Prediabetes and Type 2 Diabetes recommendation
- American Diabetes Association (ADA) — Standards of Care in Diabetes (annual update)
- National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) — Prediabetes & Insulin Resistance; Diabetes Prevention Program (DPP)
- MedlinePlus (U.S. National Library of Medicine) — Prediabetes; A1C