An A1c of 5.7% places you right at the threshold of prediabetes. It corresponds to an estimated average blood sugar of about 117 mg/dL over the past two to three months. You’re not diabetic, but your blood sugar is no longer in the normal range, which ends at 5.6%. The good news: this is the earliest possible warning, and the point where lifestyle changes have the most impact.
What 5.7% Means on the A1c Scale
The A1c test measures the percentage of your red blood cells that have glucose attached to them. Because red blood cells live about three months, the test reflects your average blood sugar over that window rather than a single moment in time. The standard ranges break down simply: below 5.7% is normal, 5.7% to 6.4% is prediabetes, and 6.5% or higher on two separate tests indicates type 2 diabetes.
At 5.7%, you’re at the very bottom of the prediabetes range. That matters because the risk of complications rises as the number climbs toward 6.4%. Your body is still managing blood sugar reasonably well, but insulin is working harder than it should to keep up.
Why Prediabetes Itself Carries Risk
It’s tempting to treat prediabetes as a non-issue since you don’t have diabetes. But a large study tracking over 10,000 people for roughly 30 years found that prediabetes on its own, even when it never progresses to diabetes, raises the long-term risk of heart disease by about 30%, heart failure by 28%, and chronic kidney disease by 20%. These elevated risks persisted after researchers accounted for whether someone eventually developed diabetes. In fact, progression to diabetes explained less than a quarter of the excess risk. Prediabetes itself was doing most of the damage.
This doesn’t mean complications are inevitable. It means that 5.7% is worth taking seriously now rather than waiting until the number climbs higher.
Your Odds of Progressing to Diabetes
Not everyone with prediabetes develops type 2 diabetes. At age 45, the 10-year risk of progressing sits around 9% to 14% depending on sex, with women facing slightly higher odds. Over a full lifetime, though, the numbers are more sobering: roughly 46% to 58% of people with prediabetes (as defined by A1c) will eventually develop diabetes if nothing changes. Those are population averages, not personal destiny. Your individual trajectory depends heavily on what you do next.
The Weight Loss and Exercise Targets That Work
The strongest evidence for reversing prediabetes comes from the Diabetes Prevention Program, a landmark trial that followed participants for 15 years. The lifestyle group aimed for two specific targets: losing 7% of their body weight and getting 150 minutes per week of moderate-intensity physical activity. In the first three years, that combination cut the rate of new diabetes diagnoses by 58%. Over 15 years of follow-up, the reduction settled at 27%, still significant and still better than medication alone.
For someone weighing 200 pounds, 7% weight loss means about 14 pounds. That’s a meaningful but realistic goal, and the research suggests you don’t need to hit an “ideal” weight to see benefits. Even modest weight loss improves how your body uses insulin.
On the exercise side, 150 minutes per week breaks down to about 30 minutes on five days. Brisk walking counts. The combination of aerobic exercise and resistance training (weights, resistance bands, bodyweight exercises) works better than either alone. Adding two to three strength sessions per week on top of your cardio can lower A1c by roughly half a percentage point on its own, which at 5.7% could potentially bring you back into the normal range. If you’re younger and already fairly fit, 75 minutes per week of vigorous activity (running, cycling, swimming at a hard pace) can achieve similar results.
What to Change About Your Diet
The DPP study used a low-calorie, low-fat dietary approach, but more recent evidence suggests the specifics matter less than the overall pattern: eat in a way that helps you lose a moderate amount of weight and sustain it. Reducing refined carbohydrates (white bread, sugary drinks, pastries) has the most direct effect on blood sugar. Replacing them with fiber-rich foods like vegetables, legumes, and whole grains slows glucose absorption and reduces the insulin spikes that drive prediabetes forward.
You don’t need to follow a named diet. The core principle is straightforward: fewer processed carbs, more fiber and protein, and a calorie intake that moves your weight gradually downward.
When Medication Enters the Picture
At 5.7%, medication is not the first-line recommendation. The ADA suggests considering metformin for people with prediabetes who have additional risk factors: a BMI of 35 or higher, age under 60, a history of gestational diabetes, or a rising A1c despite lifestyle changes. In the DPP trial, metformin reduced diabetes incidence by 18% over 15 years, roughly half the benefit of lifestyle changes alone. For most people at 5.7%, the focus should be on diet and exercise first, with medication as a backup if those efforts aren’t moving the number.
How Often to Retest
Once you’re in the prediabetes range, the ADA recommends annual A1c testing rather than the standard three-year interval used for general screening. This lets you and your doctor track whether your changes are working or whether the number is drifting upward. If your A1c drops below 5.7% on a follow-up test, that’s a genuine reversal, though staying there requires maintaining the habits that got you there.
Some providers may also check fasting glucose or order an oral glucose tolerance test for a more complete picture, especially if your A1c is borderline and other risk factors are present. The A1c alone can occasionally be affected by conditions that change red blood cell turnover, like anemia or recent blood loss, so a second type of test can confirm the result.