An A1c of 5.9% falls in the prediabetes range, which spans from 5.7% to 6.4%. This means your average blood sugar over the past two to three months has been higher than normal but not high enough to qualify as type 2 diabetes (6.5% or above). The good news: prediabetes is reversible, and a 5.9% result gives you a meaningful window to act before things progress.
What a 5.9% A1c Actually Means
Your A1c reflects a two- to three-month average of blood sugar levels, not a single snapshot. At 5.9%, you’re roughly in the middle of the prediabetes range. Your body is likely becoming less efficient at using insulin to move sugar out of the bloodstream, a process called insulin resistance. This doesn’t mean diabetes is inevitable. A large pooled analysis of 19 prospective studies published in The Lancet Global Health found that when people with prediabetes did transition to a different category, reversion to normal blood sugar (36.1%) was nearly three times more common than progression to type 2 diabetes (12.5%) over a 10-year period.
That said, without changes, roughly 5 to 10% of people with prediabetes develop type 2 diabetes each year. The higher your fasting blood sugar within the prediabetes range, the more that balance shifts toward progression rather than reversal. So a 5.9% result is a clear signal to take action, but it’s also a point where action is most effective.
Why It Matters Beyond Diabetes Risk
Most people think of prediabetes as just a warning sign for diabetes, but some damage can start even before blood sugar crosses the diabetes threshold. A systematic review and meta-analysis of over 21,000 studies found that retinopathy (damage to the small blood vessels in the eye) was detectable at A1c levels as low as 5.7%. The researchers concluded that clinical retinal screening may be worth considering at prediabetic levels, not just after a diabetes diagnosis. Kidney-related complications have also been observed in prediabetes, though the evidence there is thinner. This is one reason your result deserves more than a “wait and see” approach.
Lose a Modest Amount of Weight
If you’re carrying extra weight, even a small reduction makes a disproportionately large difference. The landmark Diabetes Prevention Program study found that losing just 5 to 7% of body weight reduced the risk of developing type 2 diabetes by 58%. For someone weighing 200 pounds, that’s 10 to 14 pounds. You don’t need to hit an “ideal” body weight. That relatively small loss improves how your cells respond to insulin and lowers the amount of sugar circulating in your blood.
Shift What You Eat
No single food will fix a 5.9% A1c, but your overall dietary pattern matters enormously. A Mediterranean-style diet, built around vegetables, whole grains, legumes, fish, olive oil, and nuts, has strong evidence behind it. A study from the Bialystok PLUS cohort found that each additional point of adherence to a Mediterranean diet was associated with a 10% lower risk of prediabetes, after adjusting for age, sex, calorie intake, alcohol, and smoking. Higher adherence also correlated with lower insulin resistance, lower inflammatory markers, and less abdominal fat.
The practical changes that matter most: replace refined carbohydrates (white bread, sugary drinks, processed snacks) with fiber-rich alternatives. Pair carbohydrates with protein or healthy fat to slow the blood sugar spike after meals. You don’t need to count every gram of anything. Focus on building meals around vegetables, lean protein, and whole grains, and limiting the foods that cause rapid blood sugar swings.
Move More, Consistently
Physical activity directly improves insulin sensitivity, meaning your cells get better at pulling sugar from the bloodstream. The target for people with prediabetes is at least 150 minutes per week of moderate to vigorous exercise, or roughly 30 minutes on most days. Walking counts. So does cycling, swimming, or any activity that gets your heart rate up. If you’re starting from very little activity, aiming for 10,000 daily steps is another practical benchmark. Resistance training (bodyweight exercises, weights, resistance bands) also helps because muscle tissue is one of the biggest consumers of blood sugar in your body.
Prioritize Sleep
Sleep is an underappreciated factor in blood sugar control. When you’re sleep-deprived, your body produces more cortisol, a stress hormone that directly promotes insulin resistance and raises blood sugar. A systematic review linking sleep patterns to type 2 diabetes found that insufficient sleep and poor sleep quality were associated with higher A1c levels. Adults need at least seven hours per night, and most do best with seven to nine. If you’re consistently getting less than that, improving your sleep may lower your A1c even without other changes.
When Medication Enters the Picture
Lifestyle changes are the first-line approach for prediabetes, and for most people with an A1c of 5.9%, they’re sufficient. However, the American Diabetes Association recommends that doctors consider prescribing metformin for people with prediabetes who have additional risk factors: a BMI of 35 or higher, age under 60, or a history of gestational diabetes. Metformin may also be considered if your A1c keeps rising despite lifestyle changes. This isn’t something you’d typically start on your own. It’s a conversation to have with your doctor if the lifestyle approach isn’t moving your numbers.
How Often to Retest
After a 5.9% result, the CDC recommends repeating your A1c test every one to two years. If you make significant lifestyle changes in the first few months, it’s reasonable to retest sooner, around the three- to six-month mark, to see whether your efforts are showing up in the numbers. Since A1c reflects a two- to three-month average, testing earlier than three months won’t capture the full effect of recent changes. Keep in mind that certain conditions, like anemia or recent blood loss, can make A1c readings less accurate, so mention these to your doctor if they apply.
A Realistic Action Plan
You don’t need to overhaul your life overnight. The most effective approach combines several moderate changes rather than one extreme one. A practical starting point looks like this:
- Weight: Aim to lose 5 to 7% of your current body weight over the next 6 to 12 months if you’re above a healthy weight.
- Diet: Build meals around vegetables, whole grains, and lean protein. Cut back on sugary drinks, refined carbs, and processed foods. A Mediterranean-style pattern is a well-studied framework.
- Exercise: Work up to 150 minutes of moderate activity per week. Start where you are and build gradually.
- Sleep: Target seven to nine hours per night. Consistent sleep and wake times help more than trying to “catch up” on weekends.
- Monitoring: Retest your A1c in three to six months to gauge progress, then every one to two years if you’re on track.
The Diabetes Prevention Program results are worth remembering: a 58% reduction in diabetes risk came from modest weight loss and regular physical activity, not extreme measures. At 5.9%, you have real leverage to push your numbers back into the normal range.