Prediabetes is a warning sign your blood sugar is climbing, but it is not yet diabetes

Prediabetes means your blood sugar levels are higher than normal but not high enough to be diagnosed as type 2 diabetes. Your fasting blood sugar is between 100 and 125 mg/dL, or your A1C (a measure of average blood sugar over three months) is between 5.7% and 6.4%. At this stage, your body is becoming less able to use insulin effectively, but the damage is not yet permanent. The important fact: prediabetes is reversible. People who catch it at this point and make changes to diet and exercise can return to normal blood sugar levels and never develop diabetes.

Your doctor finds prediabetes through a blood test, usually during a routine checkup or when screening for risk factors. Many people have prediabetes without knowing it because there are no symptoms. You cannot feel high blood sugar the way you feel hunger or pain. This is why screening matters, especially if you have risk factors like being overweight, having a family history of diabetes, or being over 45.

Key Takeaways

  • Prediabetes is diagnosed when fasting blood sugar is 100–125 mg/dL or A1C is 5.7%–6.4%, and it has no symptoms, so you need a blood test to know you have it.
  • Losing 5 to 10 percent of your body weight and exercising 150 minutes per week can reverse prediabetes and return blood sugar to normal range.
  • The biggest dietary change is reducing refined carbohydrates and added sugars, not eliminating carbs entirely.
  • If lifestyle changes alone do not work after three to six months, your doctor may prescribe metformin, a medication that slows how your body processes glucose.

Who is at higher risk for prediabetes

Prediabetes is more common in people who are overweight or have obesity, especially if extra weight is carried around the abdomen. Age matters too—risk rises after 45, though prediabetes is increasingly diagnosed in younger adults and children. Family history is a strong predictor: if a parent or sibling has type 2 diabetes, your risk is higher.

Other risk factors include high blood pressure, low HDL cholesterol (the "good" kind), high triglycerides, a history of gestational diabetes during pregnancy, or polycystic ovary syndrome (PCOS). Race and ethnicity also play a role—prediabetes is more common in Hispanic, Black, Native American, and Asian American populations. Physical inactivity and a diet high in processed foods and added sugars increase risk regardless of other factors.

If you have any of these risk factors, ask your doctor about blood sugar screening. The American Diabetes Association recommends screening for all adults over 45, and for younger adults who are overweight and have at least one additional risk factor.

How lifestyle changes reverse prediabetes

The Diabetes Prevention Program, a major research study funded by the National Institutes of Health, showed that people with prediabetes who lost 5 to 10 percent of their body weight and exercised regularly reduced their risk of developing diabetes by 58 percent. For people over 60, the reduction was 71 percent. These were not extreme changes—the study participants did not need to reach an "ideal" weight or train like athletes.

Weight loss works because excess body fat, particularly around the organs, makes cells less responsive to insulin. When you lose weight, your cells become more sensitive to insulin again, and blood sugar levels drop. The weight loss does not have to be fast. Losing one to two pounds per week is sustainable and effective. Even if you do not reach a "normal" weight, the improvement in insulin sensitivity begins as soon as you start losing.

Exercise improves insulin sensitivity independently of weight loss. Muscles use glucose for energy, so when you exercise, your muscles pull glucose from the bloodstream without needing as much insulin. This effect happens even during the first workout and builds over time. Both aerobic exercise (walking, cycling, swimming) and resistance training (weights, bodyweight exercises) work. The goal is 150 minutes of moderate-intensity aerobic activity per week, spread across at least three days, plus resistance training two or more days per week.

Dietary changes that lower blood sugar

The most important dietary change is reducing refined carbohydrates and added sugars. Refined carbs—white bread, white rice, sugary cereals, pastries—cause rapid spikes in blood sugar because they are broken down quickly. Your pancreas responds by releasing large amounts of insulin, and over time, cells become less responsive to these repeated spikes. Whole grains, legumes, and vegetables break down more slowly, causing a gentler rise in blood sugar.

This does not mean eliminating carbohydrates. Carbs are necessary for energy and health. The change is choosing carbohydrates that are high in fiber and lower on the glycemic index—foods like oatmeal, quinoa, beans, sweet potatoes, and non-starchy vegetables. Fiber slows digestion and helps prevent blood sugar spikes. Aim to include fiber at every meal.

Protein and healthy fats also matter. Protein helps you feel full longer and does not cause blood sugar spikes the way refined carbs do. Include lean proteins like chicken, fish, eggs, and legumes at meals. Healthy fats from olive oil, nuts, seeds, and avocados support heart health and help with satiety. Limit saturated fat and avoid trans fats, which are often found in processed foods.

Portion size is relevant too. Even healthy foods raise blood sugar if you eat too much. A practical approach is filling half your plate with non-starchy vegetables, one quarter with lean protein, and one quarter with whole grains or starchy vegetables. Drink water instead of sugary drinks and limit alcohol, which can cause blood sugar swings.

When to start medication alongside lifestyle changes

Lifestyle changes are the first line of treatment for prediabetes, and they work for many people. However, if blood sugar levels do not improve after three to six months of sustained effort, or if you have additional risk factors like heart disease or kidney disease, your doctor may prescribe metformin. Metformin is a medication that reduces the amount of glucose your liver produces and helps your cells use insulin more effectively.

Metformin is not a replacement for lifestyle changes—it works best when combined with diet and exercise. The medication is generally well tolerated, though some people experience digestive side effects like nausea or diarrhea, usually temporary. Metformin does not cause weight gain and may even support modest weight loss. It is one of the safest diabetes medications available and has been used for decades.

Your doctor will monitor your blood sugar with repeat A1C tests, usually every three to six months, to see whether your changes are working. If your A1C drops below 5.7%, you have reversed prediabetes. Even if medication is needed, continuing lifestyle changes remains important for long-term health.

Tracking progress and staying motivated

Checking your own blood sugar at home is not typically necessary for prediabetes management—your doctor will order A1C tests to track progress. However, some people find it helpful to see how specific foods affect their blood sugar using a home glucose meter, especially early on when learning which foods cause spikes. This can be motivating and educational, though it is not required.

More useful than frequent testing is tracking the behaviors that matter: how much you exercise, what you eat, and your weight. Many people find that keeping a simple food log or using a fitness app helps them stay consistent. The goal is not perfection—it is building sustainable habits. One missed workout or one meal of less healthy food does not undo progress. What matters is the overall pattern over weeks and months.

Working with a registered dietitian can be valuable. Dietitians can help you understand how to make changes that fit your life, your food preferences, and your budget. Many insurance plans cover dietitian visits when referred by a doctor for prediabetes management. A diabetes prevention program, offered through some health systems and community organizations, provides structured support and has been shown to improve outcomes.

What happens if prediabetes progresses to diabetes

If blood sugar continues to rise despite lifestyle changes and medication, prediabetes progresses to type 2 diabetes. This means your A1C reaches 6.5% or higher, or your fasting blood sugar is 126 mg/dL or higher. At this point, your pancreas is no longer producing enough insulin to keep blood sugar in a healthy range, and the damage to blood vessels and nerves begins to accelerate.

Type 2 diabetes requires more intensive treatment, often with multiple medications, and carries increased risk of heart disease, stroke, kidney disease, vision loss, and nerve damage. These complications develop over years, but the risk is real. This is why catching prediabetes and acting on it matters so much—you have a window of time when the condition is fully reversible.

The encouraging fact is that even people who do develop type 2 diabetes can still benefit from the same lifestyle changes. Weight loss, exercise, and dietary improvements reduce complications and sometimes allow people to reduce or stop medications. The earlier you start, the better the outcome.

Frequently Asked Questions

Can you have prediabetes without being overweight?

Yes. While obesity is a risk factor, prediabetes occurs in people of normal weight too, especially those who are sedentary or have a family history of diabetes. Excess weight around the abdomen matters more than overall weight. Thin people can have insulin resistance if they do not exercise and eat a diet high in refined carbs.

How quickly can you reverse prediabetes?

Blood sugar can improve within weeks of starting lifestyle changes, though A1C tests (which measure average blood sugar over three months) show the clearest picture. Most people see meaningful improvement within three to six months of consistent diet and exercise changes. Full reversal to normal A1C levels typically takes several months to a year.

Do you need to exercise every single day?

No. The goal is 150 minutes of moderate-intensity exercise per week, spread across at least three days. This could be five 30-minute sessions or three 50-minute sessions. Consistency matters more than daily activity. Rest days are important for recovery and help prevent burnout.

If I reverse my prediabetes, can it come back?

Yes, it can. Prediabetes returns if you stop exercising and return to old eating habits. This is why the focus is on building sustainable changes, not temporary diets. Many people maintain their improvements long-term because they feel better with more energy and better sleep when they exercise and eat well.

What if I cannot lose weight but I exercise regularly?

Exercise alone improves insulin sensitivity even without weight loss, though the effect is stronger when combined with weight loss. If you are exercising consistently and eating well but not losing weight, talk to your doctor about whether other factors like thyroid problems, medications, or sleep issues are involved. Metformin may also help if lifestyle changes alone are not enough.