Lowering your A1c is achievable through a combination of dietary changes, exercise, sleep, and weight management, with most people seeing measurable results within three months. An A1c below 7% is the standard target for most adults with diabetes, though lower is often better if you can get there without side effects. Here’s what actually moves the needle, and by how much.
Why It Takes Three Months to See Change
Your A1c reflects the average amount of glucose that has chemically bonded to your red blood cells. Since red blood cells live about 120 days, the test captures a rolling window of your blood sugar over the past two to three months. But the weighting isn’t even: roughly half of the reading comes from the most recent 30 days, about 40% from days 31 through 90, and only 10% from beyond that. This means changes you make today will show up most strongly on your next test, not the one after. Three months is the minimum realistic timeline for a lifestyle change to fully register.
Cut Carbohydrates Strategically
Reducing carbohydrate intake is one of the most effective dietary levers for lowering A1c. In a community-based study published in BMJ Open Diabetes Research & Care, people following a low-carbohydrate, high-fat diet saw their A1c drop by 1.29 percentage points more than a usual-care group, while also losing about 28 pounds on average. That’s a substantial swing, enough to move someone from poorly controlled diabetes into a much safer range.
The effect is strongest early on. A meta-analysis of 36 trials found the biggest A1c reduction, about 1.38 percentage points, happened in the first eight weeks of carb restriction. By 8 to 16 weeks the advantage over low-fat diets narrowed to about half a point. This doesn’t mean low-carb stops working; it means your body adapts and initial gains level off. The practical takeaway: a low-carb approach can produce fast, meaningful results, but you need to sustain it for the benefits to stick.
You don’t necessarily need to go keto. Simply swapping refined grains and sugary foods for vegetables, legumes, nuts, and whole grains makes a real difference. Fiber plays a specific role here. People with the highest fiber intake are about half as likely to have poor blood sugar control compared to those eating the least. The American Diabetes Association recommends at least 24 grams of total fiber daily, with roughly 8 grams coming from soluble fiber (the kind found in oats, beans, and flaxseed). Soluble fiber slows the absorption of sugar into your bloodstream, blunting post-meal glucose spikes.
Exercise: Combine Cardio and Strength Training
Exercise lowers A1c by helping your muscles pull glucose out of the bloodstream more efficiently, both during activity and for hours afterward. The most effective approach combines aerobic exercise (walking, cycling, swimming) with resistance training (weights, bands, bodyweight exercises). In a 12-week randomized trial, people who did both types three times a week saw their A1c drop from 8.4% to 7.1%, a reduction of 1.3 percentage points. That’s comparable to starting a new medication.
The program in that study involved brisk walking or cycling at moderate intensity plus 8 to 10 resistance exercises at moderate loads. You don’t need a gym membership to replicate this. A 30-minute walk followed by 15 to 20 minutes of bodyweight squats, push-ups, and resistance band work, done three days a week, follows the same general template. Consistency matters more than intensity, especially if you’re starting from a sedentary baseline.
Lose Weight, Even Modestly
Weight loss and A1c reduction go hand in hand. In a study comparing different intensities of behavioral weight loss programs, people who lost about 24 pounds saw their A1c drop by 0.11 percentage points, while those who lost about 14 pounds saw a 0.03-point drop. These numbers were in people with prediabetes, where A1c levels are already closer to normal and harder to budge. For people with higher starting A1c levels, the effect of weight loss is typically more dramatic, especially when combined with dietary and exercise changes.
The key insight is that you don’t need to reach an ideal body weight. Even 5% to 10% of your starting weight can meaningfully improve insulin sensitivity and lower average blood sugar.
Fix Your Sleep
Sleep is an underappreciated factor in blood sugar control. Insufficient sleep increases cortisol, a stress hormone that directly raises blood sugar levels and, over time, A1c. Research shows a U-shaped relationship between sleep and blood sugar control: both too little and too much sleep are linked to higher A1c. The sweet spot for most adults is seven to eight hours.
Poor sleep also makes it harder to manage the other factors on this list. When you’re sleep-deprived, you crave higher-calorie foods, you’re less likely to exercise, and your body handles carbohydrates less efficiently. Improving sleep hygiene (consistent bedtime, cool dark room, limiting screens before bed) is one of the lowest-effort changes with wide-reaching effects.
Monitor Your Glucose in Real Time
Continuous glucose monitors, small sensors worn on the arm or abdomen that track blood sugar around the clock, have proven remarkably effective at helping people lower A1c. In a large real-world study of over 1,000 people, starting a CGM was associated with an average A1c reduction of 0.7 percentage points. People with type 2 diabetes who weren’t on insulin saw the biggest benefit: a 0.9-point drop, from 8.2% to 7.3%.
The value of a CGM isn’t the device itself. It’s the feedback loop. You eat a meal and watch your glucose spike or stay flat in real time. Over days and weeks, you learn which foods, activities, and routines work for your body specifically. That personalized data is something a quarterly lab test simply can’t provide. CGMs are increasingly covered by insurance for people with type 2 diabetes, not just type 1.
How Medication Fits In
Lifestyle changes are the foundation, but medication often plays an important role. Metformin remains the most common first-line medication and effectively lowers blood sugar by reducing the amount of glucose your liver produces. Newer injectable medications that mimic a gut hormone called GLP-1 (you may have heard of these in the context of weight loss) tend to lower A1c even further than metformin, with one large cohort study showing an additional 0.35-point reduction over a year compared to metformin alone. These newer medications also promote significant weight loss, which compounds their blood sugar benefits.
Medication and lifestyle changes aren’t competing strategies. They’re complementary. Eating fewer refined carbohydrates, exercising regularly, sleeping well, and losing some weight will improve your A1c whether or not you’re on medication, and they often allow people to reduce their medication doses over time.
Putting It All Together
If your A1c is above 7% and you want to bring it down, the highest-impact combination looks like this: reduce refined carbohydrates and increase fiber intake, add three sessions per week of combined cardio and resistance exercise, prioritize seven to eight hours of sleep, and work toward modest weight loss. Each of these interventions can lower A1c by roughly 0.5 to 1.3 percentage points on its own, and the effects stack. If you have access to a CGM, use it to fine-tune your approach based on how your body actually responds.
Expect to wait at least three months before your next A1c test reflects the full extent of your changes. But because recent weeks are weighted most heavily in the measurement, the changes you sustain in the final month before testing will have the greatest impact on your number.