Being prediabetic means your blood sugar is higher than normal but not yet high enough to qualify as type 2 diabetes. It’s a warning stage where your body is losing its ability to manage glucose efficiently. Over 115 million American adults have prediabetes, and 8 in 10 of them don’t know it, largely because the condition rarely causes obvious symptoms.
The good news: prediabetes is reversible. It’s not a guarantee that you’ll develop diabetes, and relatively modest lifestyle changes can dramatically lower your risk.
What’s Happening Inside Your Body
Your cells run on glucose, and insulin is the hormone that shuttles glucose from your bloodstream into your cells. In prediabetes, two things start going wrong at the same time.
First, your cells become resistant to insulin. Muscle, fat, and liver cells stop responding to insulin’s signal as well as they should, so glucose builds up in the blood instead of entering cells where it’s needed. This resistance develops partly because excess body fat releases inflammatory molecules and fatty acids that interfere with insulin’s ability to do its job. Think of it like a lock and key: the key (insulin) still fits, but the lock is getting stiff and harder to turn.
Second, your pancreas starts falling behind. Initially, it compensates for the resistance by pumping out more insulin. But over time, the insulin-producing cells in your pancreas can’t keep up with the increased demand. This mismatch between what your body needs and what your pancreas can deliver is what pushes blood sugar into the prediabetic range, and eventually, if nothing changes, into full diabetes.
How Prediabetes Is Diagnosed
Prediabetes is diagnosed through one of three blood tests, each measuring blood sugar in a slightly different way:
- A1C test: Reflects your average blood sugar over the past two to three months. A result between 5.7% and 6.4% indicates prediabetes. Normal is below 5.7%, and 6.5% or higher means diabetes.
- Fasting blood glucose: Measures blood sugar after an overnight fast. A result between 100 and 125 mg/dL falls in the prediabetic range.
- Oral glucose tolerance test: Measures blood sugar two hours after drinking a sugary solution. A result between 140 and 199 mg/dL signals prediabetes.
Your doctor may use one or a combination of these tests. The A1C is the most convenient because it doesn’t require fasting, but it can be less accurate in certain situations, including pregnancy or conditions that affect red blood cells.
Who Should Get Screened
The U.S. Preventive Services Task Force recommends screening for prediabetes in adults aged 35 to 70 who are overweight or obese (a BMI of 25 or higher). If your initial test comes back normal, rescreening every three years is a reasonable schedule.
Some groups should be screened earlier or at lower weight thresholds. If you’re American Indian, Alaska Native, Black, Hispanic/Latino, or Native Hawaiian/Pacific Islander, screening before age 35 may be appropriate because these populations face a disproportionately high diabetes risk. Asian Americans may benefit from screening at a BMI of 23 or higher rather than 25, since metabolic risk tends to increase at a lower body weight in this group.
Signs You Might Notice
Prediabetes typically has no symptoms, which is why so many people are unaware of it. However, there is one visible sign worth knowing about: darkened, velvety patches of skin in body creases like the neck, armpits, or groin. This condition, called acanthosis nigricans, is a direct marker of insulin resistance and often appears before any blood test flags a problem. It’s especially common in people carrying extra weight. If you’ve noticed these patches, it’s worth asking for a blood sugar check.
Some people with prediabetes also report increased thirst, more frequent urination, or unusual fatigue, but these symptoms are more commonly associated with diabetes itself rather than the prediabetic stage.
Why It Matters Beyond Diabetes
The most obvious risk is progression to type 2 diabetes, but prediabetes raises your risk for cardiovascular problems even if you never cross that threshold. A large meta-analysis published in The BMJ found that people with prediabetes face a 6% to 20% higher risk of stroke compared to people with normal blood sugar, depending on the specific type of glucose impairment. The damage that elevated blood sugar does to blood vessels starts before a diabetes diagnosis, not after it.
How to Reverse Prediabetes
The landmark Diabetes Prevention Program trial showed that people who lost 5% to 7% of their body weight and exercised at least 150 minutes per week reduced their risk of developing type 2 diabetes by 58%. For someone weighing 200 pounds, that’s a loss of just 10 to 14 pounds. The exercise doesn’t need to be intense. Brisk walking counts, and you can spread those 150 minutes across the week however works for you.
These numbers are encouraging because they’re achievable. You don’t need to reach an ideal weight or run marathons. Small, consistent changes produce measurable results.
What to Eat
The Mediterranean diet is widely considered the best eating pattern for people with prediabetes, with its emphasis on whole grains, lean protein, healthy fats, and plenty of vegetables. A practical way to build your plate: fill half with nonstarchy vegetables like leafy greens, one quarter with whole grains such as brown rice or quinoa, and one quarter with lean protein like chicken, fish, or tofu.
Fiber is especially important because it slows the absorption of sugar into your bloodstream, preventing the sharp spikes that stress your insulin system. Aim for 25 to 30 grams per day from fruits, vegetables, and whole grains. Most Americans get about half that amount.
Limiting added sugar makes a meaningful difference. The American Heart Association recommends no more than 25 grams per day for women (about six teaspoons) and 36 grams for men (about nine teaspoons) for people at cardiovascular risk, which includes those with prediabetes. When checking nutrition labels, a good rule of thumb is to choose products where sugar is 5% or less of the daily value and avoid those where it hits 20% or more. Refined carbohydrates like white bread, white rice, and white pasta act similarly to sugar in your body, so swapping these for whole grain versions helps stabilize blood sugar throughout the day.
Exercise and Blood Sugar
Physical activity makes your muscle cells more sensitive to insulin, which is the core problem in prediabetes. This effect kicks in quickly. A single session of moderate exercise can improve your insulin sensitivity for 24 to 48 hours, and regular activity compounds those benefits over time. Both aerobic exercise (walking, cycling, swimming) and resistance training (weights, bodyweight exercises) help, and combining them works best.
How Quickly Prediabetes Can Change
Prediabetes isn’t a permanent label. Blood sugar levels can shift in either direction depending on what you do next. Some people see their A1C drop back into the normal range within three to six months of making dietary and exercise changes. Others progress to type 2 diabetes within a few years if nothing changes. The combination of high fasting glucose and impaired glucose tolerance together carries the highest risk of progression.
If your doctor has told you you’re prediabetic, the most useful next step is a follow-up A1C test in three to six months after you’ve had a chance to make changes. That gives you a concrete number to track and a timeline that keeps the condition from slipping off your radar.