Lowering your A1c is achievable through a combination of dietary changes, regular physical activity, better sleep, and consistent hydration. Most people with prediabetes (A1c of 5.7% to 6.4%) or type 2 diabetes (6.5% and above) can see meaningful reductions within two to three months, because A1c reflects your average blood sugar over the lifespan of your red blood cells, roughly 106 days.
What Your A1c Actually Measures
A1c tells you how much sugar has attached to your red blood cells over the past two to three months. Unlike a finger-stick glucose reading that captures a single moment, A1c gives you the bigger picture. A normal result is below 5.7%. Prediabetes falls between 5.7% and 6.4%, and diabetes is diagnosed at 6.5% or above.
Because your body constantly replaces old red blood cells with new ones (on average every 106 days), the changes you make today start showing up in your next A1c test. That’s the good news: consistent effort over 8 to 12 weeks will move the number.
Restructure Your Plate
The single most impactful change for most people is rethinking what fills your plate at each meal. The CDC recommends a simple visual method using a standard 9-inch dinner plate: fill half with non-starchy vegetables like broccoli, salad greens, or green beans. Fill one quarter with lean protein such as chicken, beans, tofu, or eggs. Fill the remaining quarter with carbohydrate foods like rice, bread, or starchy vegetables.
This approach works because it naturally limits the carbohydrates that spike your blood sugar while filling you up with fiber and protein that slow digestion. You don’t need to count every gram of carbs to see results, though some people find that helpful as they learn portion sizes.
Choose Slower-Digesting Carbs
Not all carbohydrates hit your bloodstream at the same speed. Foods with a low glycemic index, meaning they raise blood sugar more gradually, are consistently linked to better diabetes prevention and management. An international scientific consensus from the International Carbohydrate Quality Consortium confirmed that low-glycemic diets are particularly important for people with insulin resistance.
In practical terms, this means swapping white bread for whole grain, choosing steel-cut oats over instant, picking sweet potatoes over white, and eating whole fruit instead of drinking juice. You don’t have to memorize a glycemic index chart. The general rule is: the less processed a carbohydrate is, the slower it digests.
Eat More Fiber
Fiber, especially the soluble kind found in oats, beans, lentils, and many fruits, slows sugar absorption and helps keep blood sugar steady after meals. Current dietary guidelines recommend 22 to 34 grams of fiber per day depending on your age and sex, but most Americans get barely half that. Increasing your fiber intake gradually (to avoid digestive discomfort) is one of the simplest dietary changes with a real payoff for blood sugar control.
Move Your Body Consistently
Exercise lowers A1c through a straightforward mechanism: working muscles pull sugar out of your bloodstream for energy, and over time, regular activity makes your cells more responsive to insulin. The combination of aerobic exercise (walking, cycling, swimming) and resistance training (weights, bands, bodyweight exercises) is especially effective.
Research in people with type 2 diabetes has shown A1c reductions of 0.6 to 1.2 percentage points from combined exercise programs. In one study, participants who did both aerobic and resistance training three times per week for a year dropped their A1c from 8.3% to 7.1%. Another found a reduction from 7.7% to 6.9% with the same combination. Those are significant improvements, comparable to what some medications achieve.
You don’t need to train like an athlete. A 30-minute brisk walk five days a week, combined with two or three sessions of simple resistance exercises, puts you in the range that research supports. The key is consistency over intensity. A moderate routine you stick with for months will outperform an aggressive program you abandon after two weeks.
Prioritize Sleep
Poor sleep directly undermines blood sugar control, even if your diet and exercise are solid. When you don’t get enough rest, your body releases more cortisol, the stress hormone. Sustained high cortisol levels increase the amount of insulin circulating in your blood, promote belly fat accumulation, and push your body toward insulin resistance.
Sleep deprivation also activates your sympathetic nervous system, the fight-or-flight response, which signals your liver to dump stored glucose into your bloodstream. This raises blood sugar levels independent of what you eat. Research from Stanford Lifestyle Medicine identifies impaired cellular insulin sensitivity, altered gut bacteria, and this overactive stress response as key pathways connecting poor sleep to prediabetes and type 2 diabetes.
Aim for seven to nine hours per night. If you struggle with sleep quality, keeping a consistent bedtime, limiting screens before bed, and keeping your room cool and dark can all help. If you snore heavily or wake up feeling exhausted, talk to a doctor about sleep apnea, which is common in people with elevated blood sugar and makes both conditions worse.
Stay Hydrated
Drinking enough water plays a more direct role in blood sugar regulation than most people realize. When you’re dehydrated, your body produces more of a hormone called vasopressin, which tells your kidneys to conserve water. The problem is that vasopressin also raises blood glucose levels. People with type 2 diabetes already tend to have elevated vasopressin, and drinking too little water makes it worse.
A study on people with type 2 diabetes found that just three days of low water intake was enough to measurably impair their blood sugar response. The mechanism involved cortisol: dehydrated participants had higher cortisol levels that didn’t drop as they normally should, keeping blood sugar elevated. Staying well-hydrated won’t single-handedly fix your A1c, but chronic under-hydration works against everything else you’re doing.
Plain water is ideal. If you find it hard to drink enough, unsweetened sparkling water or water infused with fruit works fine. The goal is simply to avoid being chronically under-hydrated, which for most adults means drinking when you’re thirsty and keeping a water bottle accessible throughout the day.
Track Your Progress
Your A1c test at the doctor’s office is the gold standard for measuring progress, typically rechecked every three months. But you can also track day-to-day patterns with a standard blood glucose meter, checking before and after meals to learn which foods spike you the most.
Continuous glucose monitors (CGMs) have become more popular and provide a metric called the Glucose Management Indicator (GMI), which estimates your A1c from real-time sensor data. GMI and lab-measured A1c are strongly correlated, but they don’t always match perfectly. In one study, more than half of participants had a difference of over 0.5 percentage points between their GMI and their lab A1c. GMI is useful for spotting trends and adjusting your habits between lab tests, but it’s not a replacement for the actual blood draw.
The most practical tracking approach for most people is simple: check fasting blood sugar a few mornings per week, note what you ate the night before, and look for patterns. Over weeks, you’ll develop an intuitive sense of which meals, portion sizes, and routines keep your numbers in range. That knowledge, combined with your quarterly A1c result, gives you a clear feedback loop to keep improving.