Prediabetes is a condition where your blood sugar levels are higher than normal but not yet high enough to qualify as type 2 diabetes. An estimated 115.2 million U.S. adults have it, and many don’t know because it rarely causes obvious symptoms. Without changes, roughly 5 to 10 percent of people with prediabetes progress to type 2 diabetes each year.
What Happens in Your Body
Prediabetes centers on two connected problems: insulin resistance and a declining ability of the pancreas to keep up.
Insulin is the hormone that moves sugar from your blood into your cells for energy. In prediabetes, your cells stop responding to insulin as well as they should. Your pancreas compensates by producing more insulin, and for a while, that extra output keeps blood sugar in check. But the insulin-producing cells in the pancreas gradually lose their ability to match the demand. When insulin production can no longer compensate for the resistance, blood sugar starts creeping upward.
This imbalance between insulin sensitivity and insulin output is the core predictor of whether someone will eventually develop type 2 diabetes. The further apart those two get, the higher the risk.
How Prediabetes Is Diagnosed
Three blood tests can identify prediabetes, and any one of them is sufficient for a diagnosis:
- A1C test: Measures your average blood sugar over the past two to three months. A result of 5.7% to 6.4% indicates prediabetes. Below 5.7% is normal, and 6.5% or higher is diabetes.
- Fasting blood glucose: Taken after an overnight fast. A result of 100 to 125 mg/dL falls in the prediabetes range. Normal is below 100, and 126 or above is diabetes.
- Oral glucose tolerance test: You drink a sugary solution, then have your blood drawn two hours later. A result of 140 to 199 mg/dL signals prediabetes. Normal is below 140, and 200 or above is diabetes.
The U.S. Preventive Services Task Force recommends screening for adults aged 35 to 70 who are overweight or obese (BMI of 25 or higher). For Asian Americans, screening is recommended at a lower BMI of 23 or higher. People who are American Indian/Alaska Native, Black, Hispanic/Latino, or Native Hawaiian/Pacific Islander should consider screening earlier than 35, as these populations have a disproportionately high prevalence of diabetes. A family history of diabetes, a history of gestational diabetes, or polycystic ovarian syndrome also warrants earlier screening.
Why Most People Don’t Notice Symptoms
Prediabetes is often called a “silent” condition because the blood sugar elevation isn’t dramatic enough to produce the classic diabetes symptoms like excessive thirst or frequent urination. Most people discover it through routine bloodwork.
One visible sign worth knowing about is acanthosis nigricans: dark, thick, velvety patches of skin that develop slowly in body folds, most commonly the back of the neck, armpits, or groin. These patches can be itchy and sometimes develop small skin tags. The darkening is driven by excess insulin circulating in the blood, which stimulates skin cell growth. Not everyone with prediabetes develops these patches, but if you notice them, they are a strong signal of insulin resistance.
Health Risks Beyond Blood Sugar
Prediabetes isn’t just a warning label for future diabetes. It carries its own health consequences, and the longer it persists, the more damage it can do.
People with prediabetes have a 15% greater risk for cardiovascular disease compared to those with normal blood sugar. Elevated insulin and blood sugar levels contribute to inflammation in blood vessel walls, which accelerates plaque buildup. That’s why managing blood pressure and cholesterol matters even before a diabetes diagnosis.
The kidneys also take a hit. People with prediabetes are up to twice as likely to develop chronic kidney disease, because the kidneys work harder to filter excess sugar and waste from the blood. This strain compounds over time. The liver faces a similar problem: elevated glucose gets converted into fat that accumulates in the liver, and insulin resistance impairs the liver’s ability to break down that fat. This is a major driver of fatty liver disease.
What Actually Works to Reverse It
The most convincing evidence for reversing prediabetes comes from the Diabetes Prevention Program, a large clinical trial that tested whether lifestyle changes could prevent progression to type 2 diabetes. The results were striking: participants who lost 5 to 7 percent of their body weight (10 to 14 pounds for someone weighing 200 pounds) and exercised at least 150 minutes per week reduced their risk of developing type 2 diabetes by 58 percent.
That 150 minutes per week works out to about 30 minutes of moderate activity, like brisk walking, five days a week. The weight loss target is also intentionally modest. You don’t need to reach an ideal body weight to see meaningful improvement in insulin sensitivity.
Dietary Changes That Matter Most
Fiber plays a particularly important role. Your body doesn’t break down fiber the way it does other carbohydrates, so it doesn’t spike blood sugar. Soluble fiber, found in foods like oats, beans, lentils, and many fruits, dissolves in your stomach and forms a gel-like substance that slows digestion. This helps blunt the blood sugar surge that follows a meal. Current dietary guidelines recommend 22 to 34 grams of fiber per day depending on age and sex, though most Americans fall well short of that.
Beyond fiber, the general approach involves reducing refined carbohydrates and sugary drinks, choosing whole grains over processed ones, and building meals around vegetables, lean proteins, and healthy fats. The goal is to lower the overall sugar load your body has to process at any given time.
When Medication Enters the Picture
For some people, lifestyle changes alone may not be enough, or the risk of progression may be high enough to justify adding medication. Metformin is the most studied option for prediabetes prevention. Clinical trials found it was most effective in people younger than 60, those with a BMI above 35, and women with a history of gestational diabetes.
Doctors typically consider medication when the A1C is at the higher end of the prediabetes range (6.0% to 6.4%), especially if other risk factors are present: a strong family history of diabetes, elevated fasting glucose, or high triglyceride levels. Metformin isn’t a replacement for lifestyle changes but rather an additional tool for people whose numbers suggest they’re closer to the tipping point.
Prediabetes Can Go Both Ways
One of the most important things to understand about prediabetes is that it isn’t a one-way street. While 5 to 10 percent of people with prediabetes progress to type 2 diabetes each year without intervention, others return to normal blood sugar levels. The trajectory depends heavily on what you do with the information. Modest, sustained changes in weight, activity, and diet can shift the balance back toward normal insulin function, particularly when caught early.