Lowering your A1c from the prediabetes range (5.7% to 6.4%) back to normal is achievable with consistent lifestyle changes, and most people can see measurable results within two to three months. Your A1c reflects your average blood sugar over the lifespan of your red blood cells, which is roughly 90 to 100 days. That means changes you make today won’t fully show up on a lab test for about three months, but they start working immediately at the cellular level.
Why Three Months Is the Magic Number
A1c works by measuring how much sugar has attached to the hemoglobin inside your red blood cells. Since red blood cells live an average of 90 days in men and closer to 100 days in women, your A1c is essentially a rolling three-month average of your blood sugar. This is useful because it captures your overall pattern rather than a single snapshot. It also means you need patience: even perfect eating for two weeks won’t move the needle much on your next lab draw. Plan to retest after a full three-month cycle of sustained changes.
Rethink What You Eat, and When
You don’t necessarily need a dramatic diet overhaul. Both low-carb and Mediterranean-style eating patterns reduce A1c by similar amounts, roughly 7% to 9% in studies comparing the two head-to-head. The Mediterranean approach, which emphasizes vegetables, whole grains, legumes, fish, and olive oil, tends to be easier to stick with long-term. The low-carb route works well too, but sustainability matters more than perfection when you’re trying to shift a three-month average.
One surprisingly effective technique is changing the order you eat your food. When people ate their vegetables and protein before touching the carbohydrates on their plate, their post-meal blood sugar spikes dropped by 29% at the 30-minute mark and 37% at the 60-minute mark compared to eating carbs first. The overall glucose exposure over two hours was 73% lower. That’s a massive difference from simply rearranging the same meal. Start with your salad, chicken, or fish. Save the bread, rice, or potatoes for last.
Fiber also plays a direct role. Soluble fiber, the type found in oats, beans, lentils, and fruits like apples and citrus, slows the rate at which carbohydrates raise your blood sugar. The American Diabetes Association recommends aiming for 6 to 8 grams of soluble fiber per day. A cup of cooked oatmeal gets you about 2 grams, a cup of black beans about 4 grams. Building meals around these foods makes a measurable difference over time.
Exercise: Both Types Matter
Aerobic exercise (walking, cycling, swimming) and resistance training (weights, bands, bodyweight exercises) both improve blood sugar control in people with prediabetes, but they work through different mechanisms. In a randomized controlled trial comparing the two, aerobic exercise lowered fasting blood sugar by about 6% and resistance training lowered it by about 5%, with no statistically significant difference between the two groups. Both also produced meaningful drops in two-hour glucose tolerance, the measure of how well your body handles a sugar load.
Where resistance training pulled ahead was in reducing insulin resistance, the core problem behind prediabetes. Weight training improved insulin resistance by 18%, more than double the 8% improvement seen with aerobic exercise. Interestingly, resistance training achieved this without requiring significant weight loss, meaning it directly improves how your muscles absorb sugar from the bloodstream. Aerobic exercise, on the other hand, helped primarily through reducing body fat.
The practical takeaway: do both if you can. If you’re only going to pick one, resistance training gives you a slight edge for insulin resistance specifically. But any consistent movement, even brisk walking, is far better than being sedentary. Aim for at least 150 minutes of moderate activity per week, and include two or more sessions of some form of strength training.
Sleep Is Not Optional
Short sleep is one of the most overlooked drivers of insulin resistance. A meta-analysis of over 90,000 people found that sleeping fewer than seven hours a night increased the relative risk of developing diabetes by 28% compared to getting seven to eight hours. Sleeping too long (typically nine or more hours, often a sign of poor sleep quality) raised the risk even more, by 48%.
The metabolic damage from poor sleep looks remarkably similar to early diabetes: your muscles take up less glucose, your liver pumps out more of it, and your pancreas doesn’t release insulin efficiently. These effects appear after just a few nights of restricted sleep, and no study has ever found that sleep loss improves glucose metabolism. Poor or insufficient sleep is directly associated with higher A1c levels and greater whole-body insulin resistance. If you’re doing everything else right but sleeping five or six hours a night, you’re working against yourself.
Quit Smoking, Moderate Alcohol
Cigarette smoking raises A1c levels independently of diet and exercise. In a study of nearly 9,000 people, smokers had significantly higher A1c than non-smokers, and the effect was even larger in people who used both cigarettes and other tobacco products. Smokers also carry a 30% to 40% higher risk of developing type 2 diabetes overall. If you smoke, quitting is one of the most effective single things you can do for your blood sugar.
Alcohol is more nuanced. Light to moderate drinking (one to four times per month) was associated with slightly lower A1c in population studies, while heavier drinking showed a similar or slightly greater reduction. But these are observational findings, and alcohol carries its own health risks. If you drink moderately, there’s no urgent reason to stop on A1c grounds alone. If you don’t drink, there’s no reason to start.
What a Realistic Plan Looks Like
You don’t need to overhaul your entire life at once. Pick the changes with the biggest leverage first. For most people, that means three things: reducing refined carbohydrates and adding fiber-rich foods, starting a regular exercise routine that includes some form of resistance training, and protecting seven to eight hours of sleep. These three changes address the root problem, insulin resistance, from multiple angles simultaneously.
A reasonable first-month goal might look like this: swap your breakfast to something fiber-rich like oatmeal with berries, start eating your protein and vegetables before your starches at dinner, walk for 30 minutes five days a week, and add two short strength-training sessions. In month two, increase the intensity or duration of your workouts and start tracking whether your sleep habits are actually giving you seven-plus hours. By month three, you’ll have a full red blood cell cycle of improved habits behind you, and your A1c retest should reflect that.
Some people with prediabetes are also prescribed metformin, particularly those at higher risk due to additional factors like elevated body weight or a history of gestational diabetes. But lifestyle changes remain the first-line approach and are often enough on their own to bring A1c below 5.7%. The goal isn’t just a better number on a lab test. It’s building habits that keep your blood sugar stable for years, not months.