Prediabetes: What Your Numbers Mean and How to Turn Them Around

Roughly one in three American adults has prediabetes, and most do not know it, since the condition rarely causes any symptoms on its own. It usually gets caught through a routine blood test rather than because something feels noticeably wrong.

This guide covers what the actual numbers mean, what causes prediabetes, and what the real evidence says about turning it around, since the honest answer here is more encouraging than most people expect it to be.

What the Numbers Actually Mean

Prediabetes is diagnosed with the same tests used for type 2 diabetes, just measured against a lower threshold. The current ADA criteria define it as an A1c of 5.7 to 6.4 percent, a fasting blood sugar of 100 to 125 mg/dL, or a two-hour glucose tolerance test result of 140 to 199 mg/dL. Any one of these results on its own is enough for the diagnosis; a result below these ranges is considered normal, and a result above is type 2 diabetes.

There are typically no clear symptoms of prediabetes itself, which is exactly why screening matters more than symptom-watching does. Some people already have early complications of elevated blood sugar by the time prediabetes is caught, but the number itself usually arrives quietly, on a lab report rather than through anything actually felt. Our conditions page covers the classic symptoms of full type 2 diabetes, which prediabetes generally precedes without producing on its own.

Because symptoms rarely prompt testing, screening guidelines matter more here than for most conditions. Current recommendations call for testing all adults starting at age 35, and testing earlier for anyone who is overweight and has an additional risk factor, such as a family history of diabetes or a history of gestational diabetes. A normal result does not mean testing stops permanently, and repeat screening at least every 3 years is still recommended, and at least yearly once prediabetes is diagnosed.

Read More: Type 2 Diabetes: Symptoms, Causes, Diagnosis, Treatment, and Remission

What Causes It

Prediabetes reflects the same underlying process as type 2 diabetes, insulin resistance, just earlier in its course and generally somewhat less advanced overall. Cells gradually respond less to insulin, and the body compensates by producing more until that compensation falls short, letting blood sugar drift upward over months or years.

Excess weight, particularly around the abdomen, physical inactivity, and family history are the most consistent risk factors, alongside age, since risk rises steadily after 35.

A history of gestational diabetes is a distinct and often underappreciated risk factor on its own: it identifies an underlying tendency toward insulin resistance that persists well beyond pregnancy, which is part of why postpartum screening matters even when blood sugar appeared to fully normalize immediately after delivery.

Certain ethnic groups, including Black, Hispanic, Native American, and Asian American populations, also carry a higher risk independent of weight, which factors into how early screening is recommended for some people relative to others.

Can Prediabetes Be Reversed?

Genuinely, yes, and the evidence behind this claim is unusually strong. The Diabetes Prevention Program, a landmark randomized trial of more than 3,000 people with prediabetes, found that a structured lifestyle program reduced progression to type 2 diabetes by 58 percent compared to placebo over an average of 2.8 years.

The lifestyle goals in that trial were specific: roughly 7 percent body weight loss and 150 minutes of physical activity per week, evidence-based targets worth discussing with a clinician rather than a rigid program to follow without guidance suited to your own health history.

Meaningful change can show up faster than the full trial length suggests. A follow-up analysis found that people who lost more than 5 percent of their body weight saw prediabetes fully resolve, meaning blood sugar returned to a normal range, in a majority of cases within about a year. Individual timelines still vary considerably, and results depend on how consistently people sustain the changes rather than on the specific number of months that pass.

Age does not appear to be a barrier: NIDDK reporting on the original trial found the lifestyle program worked particularly well in adults 60 and older, reducing progression by 71 percent in that age group specifically, somewhat higher than the overall average.

Does Metformin Help?

For some people, yes, though it is generally positioned as an addition rather than a full substitute. Current ADA guidance recommends considering the following option for adults at higher risk.

• Metformin, specifically for adults under 60 with a BMI of 35 or above, a fasting glucose of 110 mg/dL or higher, an A1c of 6.0 percent or higher, or a history of gestational diabetes

In the original trial, metformin reduced progression to type 2 diabetes by 31 percent, meaningful but less effective than the lifestyle program on its own, which is why it is generally reserved for higher-risk cases or for people who have already tried lifestyle change without enough improvement.

Where to Start

If a recent lab result mentioned prediabetes, ask specifically which test was used and what the actual number was: A1c, fasting glucose, or the tolerance test, since that specific number is what a clinician will track over time rather than the label alone.

Ask, too, whether you fall into one of the higher-risk categories where metformin is typically considered alongside lifestyle change, and whether a structured program modeled on the original research is available or covered through your insurance.

Read More: Type 2 Diabetes: Symptoms, Causes, Diagnosis, Treatment, and Remission