Published: December 2022
Last updated: September 21, 2026
Next review: September 2027, or sooner if major diabetes guidance changes.
Written and source-checked by: Adel Galal, Founder and Lead Writer at NextFitLife
Medical review status: This article has not been medically reviewed by an endocrinologist, diabetes specialist, registered dietitian, pharmacist, or other licensed healthcare professional.
Prediabetes causes are closely linked with the way your body uses insulin. In many people, cells stop responding to insulin as well as they should. The pancreas then works harder to keep blood sugar normal. Over time, blood sugar can rise into the prediabetes range.
That is the core process. Other things such as family history, excess abdominal fat, low activity, age, PCOS, past gestational diabetes, smoking, some medicines, and other health problems can raise the chance that this process develops.
Prediabetes does not mean type 2 diabetes is certain. Many people can lower their blood sugar and reduce their risk with food changes, movement, weight care when needed, better sleep, smoking cessation, and medical treatment when appropriate.
For another practical guide, read Prediabetes NHS: Prevention, Tests, and Daily Care.
Medical Notice
I am not a dermatologist or A doctor, and this content does not replace professional medical advice. What I share comes from real-life experience, extensive research, and consultation with healthcare providers. Always consult qualified medical professionals for diagnosis and treatment of any health condition.
Prediabetes should be diagnosed with proper blood tests. A home glucose meter, smartwatch, or continuous glucose monitor should not be used by itself to diagnose prediabetes.
Do not start, stop, or change metformin, weight medicine, steroids, hormone medicine, or another prescription based on this article.
Table of Contents
- Quick Answer
- What Prediabetes Means
- Prediabetes Test Ranges
- 11 Causes and Risk Factors
- Who Should Be Tested?
- Best Treatment Steps
- When Metformin May Help
- What About Weight Loss Medicines?
- Can Prediabetes Return to Normal?
- Symptoms to Watch
- How Often to Recheck
- References and Sources
- Conclusion
- Internal Links and Hub
- About the Author
- Frequently Asked Questions
Quick Answer: What Are the Main Prediabetes Causes?
The main process behind prediabetes causes is often insulin resistance. Your body still makes insulin, but your muscle, fat, and liver cells do not respond to it as well. The pancreas makes more insulin to keep blood sugar controlled. Over time, it may not be able to keep up.
Genes, excess abdominal fat, low activity, age, pregnancy history, PCOS, smoking, poor sleep, some medicines, and other metabolic problems can increase this risk.
What Is Prediabetes?
Prediabetes means your blood sugar is higher than normal but has not reached the range used to diagnose diabetes.
It is not the same as type 2 diabetes.
It is also not something to ignore.
Prediabetes raises the risk of future type 2 diabetes. It is also linked with higher heart and blood vessel risk.
The good news is that early action can make a real difference.
What Blood Sugar Levels Count as Prediabetes?
The American Diabetes Association uses three main tests.
| Test | Normal Range | Prediabetes Range | Diabetes Range |
|---|---|---|---|
| A1C | Below 5.7% | 5.7% to 6.4% | 6.5% or higher |
| Fasting glucose | Below 100 mg/dL | 100 to 125 mg/dL | 126 mg/dL or higher |
| Two hour glucose test | Below 140 mg/dL | 140 to 199 mg/dL | 200 mg/dL or higher |
The two hour test is done after drinking a measured glucose drink during an oral glucose tolerance test.
A1C does not require fasting.
A fasting glucose test does.
Some health problems can make A1C harder to read. These include some blood disorders, anemia, pregnancy, recent blood loss, or conditions that change how long red blood cells live.
If a result looks unusual, your clinician may use another test.
11 Prediabetes Causes and Risk Factors to Know
1. Insulin Resistance
Insulin resistance is the main process behind most prediabetes that comes before type 2 diabetes.
Insulin is a hormone made by the pancreas. It helps glucose move from your blood into your cells.
When cells stop responding well, the pancreas tries to make more insulin. This can work for years.
Later, the pancreas may not be able to make enough insulin to keep blood sugar normal.
That is when glucose begins to rise.
2. Excess Abdominal Fat
Having overweight or obesity can raise the risk of prediabetes, but body fat location also matters.
Fat stored around the belly and organs is called visceral fat. It is closely linked with insulin resistance.
This does not mean every person with overweight has prediabetes. It also does not mean a person at a lower weight cannot develop it.
Weight is one risk factor, not the whole story.
3. Low Physical Activity
Muscles use glucose for energy.
Regular movement also helps cells respond better to insulin.
Long periods with very little activity can make insulin resistance worse, especially when other risk factors are present.
This is why walking, cycling, swimming, strength work, and other forms of regular movement are a major part of diabetes prevention.
For more daily ideas, see Diabetes Lifestyle Routines.
4. Family History and Genes
Prediabetes and type 2 diabetes can run in families.
Having a parent, brother, or sister with type 2 diabetes raises your risk.
Genes affect how the body stores fat, makes insulin, and responds to insulin.
A family history does not mean diabetes is certain. It means screening and early action become more useful.
5. Age
Risk tends to rise with age.
The 2026 ADA Standards say routine testing should begin at age 35 for adults who do not already meet earlier testing rules.
That does not mean people younger than 35 cannot have prediabetes.
Younger adults and even children can develop it when other risks are present.
6. A History of Gestational Diabetes
Gestational diabetes is diabetes that starts during pregnancy.
Blood sugar often improves after birth, but future risk does not disappear.
People with a history of gestational diabetes have a higher risk of later prediabetes and type 2 diabetes.
The ADA recommends ongoing glucose testing after a pregnancy affected by gestational diabetes.
7. PCOS
PCOS means polycystic ovary syndrome.
Many people with PCOS also have insulin resistance. This raises the risk of prediabetes and type 2 diabetes.
PCOS may also cause irregular periods, acne, increased hair growth, trouble becoming pregnant, or dark patches of skin.
If you have PCOS, ask your clinician how often you should be screened for diabetes.
8. High Blood Pressure, High Triglycerides, or Low HDL
Prediabetes often appears as part of a wider metabolic pattern.
This can include:
- High blood pressure
- High triglycerides
- Low HDL cholesterol
- Extra abdominal fat
- Fatty liver
This group of problems is often linked with metabolic syndrome and insulin resistance.
The ADA says prediabetes should also lead to a full review of heart and blood vessel risk.
Read Diabetes and Heart Diseases for more on this link.
9. Smoking
Smoking is linked with insulin resistance and type 2 diabetes risk.
NIDDK lists smoking, including tobacco products and exposure to secondhand smoke, among factors that raise risk.
Stopping smoking helps much more than blood sugar. It also protects the heart, lungs, blood vessels, and kidneys.
10. Poor Sleep and Sleep Disorders
Sleep affects hormones, hunger, stress, and glucose control.
Sleep apnea is also common in people with insulin resistance and obesity.
Poor sleep alone does not prove that it caused prediabetes, but ongoing sleep problems can add to metabolic risk.
If you snore loudly, stop breathing in sleep, wake with headaches, or stay very sleepy during the day, ask about sleep apnea.
11. Medicines and Other Health Conditions
Some medicines can raise glucose.
Examples can include high dose or long term steroids and some other medicines that affect metabolism.
The 2026 ADA guidance also says people exposed to high risk medicines should be watched more closely.
Other conditions linked with higher risk include:
- MASLD, or metabolic fatty liver disease
- Past pancreatitis
- Some hormone disorders
- HIV
- Conditions linked with severe insulin resistance
Do not stop a medicine because it can raise glucose. Ask the prescriber what to do.
What About Race, Ethnicity, and Ancestry?
Some groups have higher rates of prediabetes and type 2 diabetes.
The ADA and CDC include ancestry and ethnicity as factors that can affect screening decisions.
This should not be treated as a simple biological cause.
Genes, food access, income, stress, health care access, environment, and other social factors can all affect risk.
Your personal health history matters more than a label alone.
Who Should Be Tested for Prediabetes?
The 2026 ADA Standards recommend considering testing at any adult age when a person has overweight or obesity plus at least one added risk factor.
Risk factors include:
- A close family member with diabetes
- High blood pressure
- Low HDL or high triglycerides
- PCOS
- Low physical activity
- Heart disease
- Signs of insulin resistance
- Metabolic fatty liver disease
For adults without these earlier reasons to test, ADA screening begins at age 35.
If a test is normal, repeat testing is usually reasonable at least every three years, though a clinician may test sooner if risk changes.
Does Prediabetes Cause Symptoms?
Most people with prediabetes feel normal.
That is one reason it is often missed.
A dark, thick patch of skin around the neck, armpits, or other skin folds can be a clue to insulin resistance. This is called acanthosis nigricans.
Symptoms such as strong thirst, frequent urination, blurry vision, unexplained weight loss, or unusual hunger are more concerning for diabetes than mild prediabetes.
Do not wait for symptoms if you already have risk factors.
What Is the Best Treatment for Prediabetes?
The strongest treatment plan is usually built around changes you can keep doing.
1. Join a Diabetes Prevention Program if You Can
The 2026 ADA Standards recommend structured prevention programs for people at high risk.
These programs do more than hand you a diet sheet.
They teach food skills, activity, problem solving, weight care, and ways to keep habits going.
The CDC National Diabetes Prevention Program uses trained coaches and a structured program.
2. Aim for 5% to 7% Weight Loss if You Have Overweight or Obesity
The ADA recommends a goal of at least 5% to 7% weight loss for people with overweight or obesity who are at high risk for type 2 diabetes.
You do not need to lose a huge amount before health can improve.
For someone who weighs 100 kilograms, 5% is 5 kilograms.
For someone who weighs 200 pounds, 5% is 10 pounds.
Your safest goal may be different if you are pregnant, older, frail, or living with another medical condition.
3. Build Toward 150 Minutes of Activity Each Week
A common prevention goal is at least 150 minutes of moderate activity each week.
Brisk walking is a simple example.
You can split the time across the week.
Start below this level if needed.
Ten minutes still counts as movement.
4. Add Strength Work
Muscle uses glucose.
Strength training can help maintain muscle and support insulin sensitivity.
Use resistance bands, body weight exercises, machines, or weights that fit your health and fitness level.
5. Choose an Eating Pattern You Can Keep
The 2026 ADA Standards highlight both Mediterranean style and low carbohydrate patterns as evidence based options for people at risk of type 2 diabetes.
You do not need to follow one named diet perfectly.
A strong food pattern usually includes:
- Nonstarchy vegetables
- Whole fruit
- Beans and lentils
- Lean protein
- Whole grains when they fit your plan
- Nuts and seeds
- Suitable dairy or nondairy foods
Limit sugary drinks, sweets, refined grains, processed foods, and heavily processed meat more often.
A registered dietitian can help build a plan around your culture, budget, health, and food preferences.
6. Replace Sugary Drinks
Soda, sweet tea, sweet coffee drinks, energy drinks, and many juice drinks can add large amounts of sugar quickly.
Water is a simple main drink for most people.
Whole fruit usually makes more sense than juice because it comes with fiber and is harder to drink in large amounts.
7. Improve Sleep
Keep a regular sleep time when you can.
Reduce late caffeine, keep the room dark and quiet, and ask for help if snoring or daytime sleepiness points to sleep apnea.
Sleep care supports your whole metabolic plan.
8. Stop Smoking
If you smoke, quitting is one of the best steps you can take for long term health.
Ask about counseling, quit programs, or approved medicine if stopping on your own has been hard.
9. Treat Blood Pressure, Cholesterol, and Other Risks
Prediabetes is not only a glucose issue.
The ADA says heart risk should be reviewed too.
Blood pressure, cholesterol, smoking, kidney health, activity, weight, and family history all matter.
When Is Metformin Used for Prediabetes?
Metformin is the medicine with the strongest long term evidence for helping prevent or delay type 2 diabetes in high risk people.
The 2026 ADA Standards say it should be considered especially in adults who are at higher risk, including people who:
- Are age 25 to 59
- Have BMI of 35 or higher
- Have fasting glucose around 110 mg/dL or higher
- Have A1C around 6.0% or higher
- Have a history of gestational diabetes
Metformin is not right for everyone.
It can also lower vitamin B12 over time, so the ADA recommends periodic B12 checks in long term users, especially when anemia or nerve symptoms are present.
In the United States, metformin is widely used for diabetes prevention in selected people, but it is not FDA approved specifically as a prediabetes prevention drug.
What About GLP 1 Drugs and Other Weight Medicines?
Modern prediabetes care can include weight treatment when excess weight is a major driver of risk.
The 2026 ADA Standards say medicine can be considered to support weight goals, slow worsening blood sugar, and reduce heart risk when it fits the person's health.
This may include medicines used for obesity treatment in people who meet the medical criteria.
These medicines are not simply “prediabetes pills.”
The choice depends on weight, heart risk, side effects, cost, other conditions, and personal goals.
Do not buy GLP 1 products from unverified online sources or change a prescription without medical guidance.
Can Prediabetes Be Reversed?
Blood sugar can return to the normal range in many people.
That is good news.
Still, I prefer the phrase “return to normal glucose” over promising a permanent cure.
Your future risk can remain higher than someone who never had prediabetes, especially when strong genetic or metabolic risks are still present.
Keep the habits that helped and keep getting tested.
Does Prediabetes Always Become Diabetes?
No.
Some people progress to type 2 diabetes. Some stay in the prediabetes range for years. Others return to normal glucose levels.
Your risk is higher when glucose is closer to the diabetes range.
The 2026 ADA Standards call for more active prevention in people with higher risk, such as A1C of 6.0% or more, fasting glucose from 110 to 125 mg/dL, BMI 35 or higher, or past gestational diabetes.
Is A1C 5.7% Prediabetes?
Yes.
An A1C from 5.7% through 6.4% falls in the ADA prediabetes range.
Risk rises across that range. An A1C of 6.4% is closer to the diabetes threshold than 5.7%.
Your clinician should look at the whole picture rather than one number alone.
Is A1C 6.5% Diabetes?
An A1C of 6.5% or higher reaches the diabetes range.
When there is no clear high glucose emergency or classic symptoms, the ADA says the diagnosis should be confirmed with repeat testing or another accepted lab test.
Do not diagnose yourself from a home device.
Do I Need to Check Blood Sugar at Home With Prediabetes?
Most people with prediabetes do not need to test their glucose many times each day.
A1C, fasting glucose, and the two hour glucose test are the standard tests used for diagnosis.
The 2026 ADA Standards say there is not enough evidence to use continuous glucose monitors to diagnose prediabetes or diabetes.
Your clinician may still recommend home checks for a special reason.
Can Stress Cause Prediabetes?
Stress is not usually the single cause.
Long lasting stress can affect sleep, food choices, activity, hormones, and weight. All of these can affect glucose over time.
The better way to think about stress is as one part of the wider risk picture.
For practical tools, see Stress Reduction Techniques.
Can You Get Prediabetes if You Are Thin?
Yes.
Body weight is only one risk factor.
Family history, genes, age, PCOS, gestational diabetes, medicines, smoking, low activity, fatty liver, and other metabolic problems can raise risk even when body weight is not high.
Do not assume a normal BMI means you cannot have prediabetes.
How Often Should Prediabetes Be Checked?
The 2026 ADA Standards recommend checking people with prediabetes for progression to diabetes at least once each year.
Testing may happen more often when risk is higher.
For example, closer follow up can make sense when:
- A1C is near 6.5%
- Fasting glucose is near 126 mg/dL
- Weight is rising quickly
- A new medicine raises glucose
- Pregnancy is planned
- You had gestational diabetes
- Symptoms of diabetes appear
When Should You Call a Healthcare Professional?
Book a routine visit if you have risk factors and have not been tested.
Contact your clinician sooner if you already have prediabetes and your results are rising despite your current plan.
Seek medical assessment for symptoms such as:
- Strong thirst
- Frequent urination
- Unexplained weight loss
- Blurred vision
- Repeated infections
- Sores that heal slowly
- Severe tiredness with high glucose
These symptoms can mean glucose has moved into the diabetes range.
Common Myths About Prediabetes Causes
Myth: Eating Sugar Is the One Cause
No.
Prediabetes usually comes from a mix of insulin resistance, genetics, body fat, activity, age, and other metabolic risks.
Myth: Prediabetes Means Diabetes Is Certain
No.
Early action can lower risk and many people return their glucose to the normal range.
Myth: Thin People Cannot Get Prediabetes
No.
Weight matters, but it is not the only risk.
Myth: Metformin Is Needed for Everyone
No.
It is used mainly for selected people who have a higher chance of progressing to diabetes.
Myth: You Must Cut Out All Carbohydrates
No.
Beans, vegetables, whole fruit, and whole grains can fit a healthy plan. The amount and type of carbohydrate matter more than banning an entire food group.
Myth: Once Your A1C Falls, You Never Need Another Test
No.
Glucose can rise again. Keep your healthy habits and follow the testing plan from your clinician.
References and Sources
The medical information in this article was checked against current diabetes prevention, testing, and treatment guidance.
- American Diabetes Association: Diagnosis and Classification of Diabetes, Standards of Care in Diabetes 2026
Current guidance on A1C, fasting glucose, oral glucose tolerance testing, screening ages, risk factors, and yearly testing for people with prediabetes.
Read the ADA 2026 diagnosis guidance - American Diabetes Association: Prevention or Delay of Diabetes, Standards of Care in Diabetes 2026
Current guidance on diabetes prevention programs, lifestyle treatment, higher risk prediabetes, metformin, weight care, and follow up.
Read the ADA 2026 prevention guidance - American Diabetes Association: Positive Health Behaviors and Well Being, Standards of Care in Diabetes 2026
Current recommendations on medical nutrition therapy, 5% to 7% weight loss, vegetables, fruit, legumes, whole grains, lean protein, Mediterranean style eating, and other food patterns.
Read the ADA 2026 lifestyle guidance - Centers for Disease Control and Prevention: Prediabetes, Your Chance to Prevent Type 2 Diabetes
Public guidance on insulin resistance, risk factors, the National Diabetes Prevention Program, weight loss, and physical activity.
Read the CDC prediabetes guide - National Institute of Diabetes and Digestive and Kidney Diseases: Preventing Type 2 Diabetes
U.S. government information on prediabetes, long term lifestyle change, diabetes prevention, and metformin in selected people.
Read the NIDDK prevention guide
Conclusion: Act Before Blood Sugar Rises Further
Understanding prediabetes causes helps you see that this condition is usually about much more than sugar alone. Insulin resistance, body fat, activity, genes, age, PCOS, pregnancy history, smoking, sleep, medicines, and other metabolic problems can all shape risk.
The strongest first steps are simple: get the right blood tests, move more, choose a food pattern you can keep, work toward a healthier weight when needed, stop smoking, sleep well, and manage blood pressure and cholesterol too.
Your next step: if you have not been tested, ask whether A1C or fasting glucose is right for you. If you already have prediabetes, choose one change you can keep and review your plan with your healthcare team.
Internal Links and Hub
Continue with these NextFitLife guides for blood sugar, heart health, kidneys, weight, stress, and daily diabetes care:
- Prediabetes NHS: Prevention, Tests, and Daily Care
- Diabetes Lifestyle Routines
- Diabetes and Heart Diseases
- Kidney and Diabetes
- Weight Loss and Metabolism Hub
- Stress Reduction Techniques
Frequently Asked Questions About Prediabetes Causes
What are the main prediabetes causes?
The main process behind prediabetes causes is usually insulin resistance. Other risk factors include excess abdominal fat, low activity, family history, age, PCOS, past gestational diabetes, smoking, sleep problems, and some medicines or health conditions.
What is insulin resistance?
Insulin resistance means your cells do not respond to insulin as well as they should. Your pancreas then makes more insulin to try to keep blood sugar normal.
What A1C is prediabetes?
An A1C from 5.7% to 6.4% falls in the ADA prediabetes range.
What fasting glucose is prediabetes?
A fasting glucose from 100 to 125 mg/dL falls in the prediabetes range.
What two hour glucose result means prediabetes?
A two hour glucose value from 140 to 199 mg/dL during a 75 gram oral glucose tolerance test falls in the prediabetes range.
Can prediabetes return to normal?
Yes. Many people can bring glucose back into the normal range through lifestyle changes and, when needed, medical treatment. Continued follow up still matters because glucose can rise again.
Does prediabetes always become type 2 diabetes?
No. Some people progress, some remain stable, and some return to normal glucose levels.
Can thin people get prediabetes?
Yes. Body weight is only one risk factor. Genes, family history, age, PCOS, past gestational diabetes, medicines, smoking, and other conditions can also raise risk.
Does sugar cause prediabetes?
Sugar alone is not the only cause. A diet high in sugary drinks and refined foods can add to weight gain and insulin resistance, but genes, activity, body fat, age, medicines, and other factors also matter.
Can stress cause prediabetes?
Stress is not usually the single cause. Long term stress can affect sleep, activity, food choices, weight, and hormones, which can add to diabetes risk.
Can poor sleep raise prediabetes risk?
Poor sleep and sleep disorders can add to insulin resistance and other metabolic problems. Treating sleep apnea or ongoing poor sleep can be part of a wider risk reduction plan.
Does PCOS increase the risk of prediabetes?
Yes. PCOS is often linked with insulin resistance and a higher risk of type 2 diabetes.
Does gestational diabetes raise future risk?
Yes. A history of gestational diabetes raises the future risk of prediabetes and type 2 diabetes, even when blood sugar improves after pregnancy.
How much weight should I lose for prediabetes?
For people with overweight or obesity, the ADA recommends working toward at least 5% to 7% weight loss as part of diabetes prevention.
How much exercise helps prediabetes?
A common prevention goal is at least 150 minutes of moderate activity each week. Start smaller if needed and build up over time.
What diet is best for prediabetes?
There is no single best diet for everyone. Mediterranean style and low carbohydrate patterns both have evidence for diabetes prevention. The best plan is one that is nutritious and sustainable for you.
Is metformin used for prediabetes?
Yes, in selected people at higher risk. The ADA especially highlights younger adults with BMI 35 or higher, higher A1C or fasting glucose, and people with past gestational diabetes.
Does everyone with prediabetes need metformin?
No. Lifestyle treatment is the main first step for many people. Metformin is considered more often when the risk of diabetes is higher.
Do I need to check blood sugar every day?
Most people with prediabetes do not need to check several times every day. Your clinician will decide whether home testing is useful for your situation.
How often should prediabetes be checked?
The 2026 ADA Standards recommend testing people with prediabetes for progression to diabetes at least once each year.
When should I see a doctor?
See a healthcare professional if you have risk factors, an abnormal A1C or glucose result, or symptoms such as strong thirst, frequent urination, blurred vision, unexplained weight loss, or repeated infections.
Health & wellness writer with 30+ years of experience in nutrition, fitness, and healthy aging. Founder of NextFitLife.com — evidence-based health guidance.
