Lowering your A1C is possible through a combination of dietary changes, exercise, weight management, and better sleep. Most people see meaningful results within three months, because the A1C test reflects your average blood sugar over roughly the past 70 days. How much your number drops depends heavily on where you’re starting: someone with an A1C of 10% can expect a much larger reduction from the same lifestyle changes than someone starting at 7%.
For reference, a normal A1C is below 5.7%. The prediabetes range is 5.7% to 6.4%, and an A1C of 6.5% or higher indicates diabetes.
Why A1C Takes Months to Change
A1C measures how much sugar has attached to the hemoglobin inside your red blood cells. This process, called glycation, happens gradually over the entire life of each red blood cell. It takes about 70 days for hemoglobin to reach its full glycation level at a given blood sugar, which is why the test captures a two- to three-month window rather than a single moment. This also means you won’t see your full progress on a retest taken just a few weeks after making changes. Plan to retest at three months if you’ve recently changed your diet, exercise routine, or medication. If your numbers are stable and on track, every six months is sufficient.
Shift to Lower Glycemic Foods
The single most impactful dietary change for A1C is choosing foods that raise blood sugar more slowly. Low glycemic index (GI) diets, which emphasize whole grains, legumes, non-starchy vegetables, and most fruits over refined carbohydrates, reduce A1C by about 0.4 to 0.5 percentage points compared to higher GI diets. That may sound modest, but for someone in the prediabetes or early diabetes range, half a point can be the difference between categories.
In practice, this means swapping white rice for brown or cauliflower rice, choosing steel-cut oats over instant, eating whole fruit instead of drinking juice, and pairing carbohydrates with protein or fat to slow digestion. You don’t need to eliminate carbs entirely. The goal is to avoid the sharp blood sugar spikes that come from processed grains, sugary drinks, and starchy foods eaten on their own. Paying attention to portion size matters too: even low GI foods raise blood sugar if you eat large quantities.
Combine Cardio and Strength Training
Exercise lowers blood sugar both immediately (your muscles absorb glucose during activity) and over time (regular training improves insulin sensitivity). But the type of exercise matters. A study published in JAMA compared aerobic exercise, resistance training, and a combination of both in people with type 2 diabetes. Neither cardio alone nor weight training alone produced a statistically significant A1C reduction compared to the control group. The combination of both, however, lowered A1C by 0.34 percentage points, and that result was statistically significant.
This doesn’t mean cardio or weights are useless on their own. Both improve cardiovascular health, body composition, and blood sugar in the short term. But if your primary goal is bringing down your A1C number, doing both gives you the best shot. A reasonable starting point is three days of moderate cardio (brisk walking, cycling, swimming) and two days of resistance training per week. Even 150 minutes total per week makes a difference.
Weight Loss Helps, but Starting A1C Matters More
Losing weight is often recommended as a path to a lower A1C, and it does help, but the relationship is more nuanced than “lose X pounds, drop Y points.” A 13-year observational study of people in intensive lifestyle programs found that participants with the highest starting A1C levels (the most elevated blood sugar) saw the greatest reductions, averaging a 2.5 percentage point drop. Those with moderately high A1C dropped about 1.2 points, and those with the lowest baseline dropped about 0.5 points. The amount of weight each group lost was essentially the same.
The takeaway: if your A1C is quite high, lifestyle changes can produce dramatic improvements. If your A1C is already close to target, the same effort yields smaller but still meaningful reductions. Weight loss supports the process, but it’s not the only driver. The dietary and exercise changes that lead to weight loss are doing much of the heavy lifting on their own.
Sleep and Stress Affect Blood Sugar Directly
Poor sleep does more than leave you tired. It triggers a hormonal cascade that raises blood sugar independently of what you eat. When you sleep badly, your body produces more cortisol, a stress hormone that tells the liver to release stored glucose and simultaneously makes your cells less responsive to insulin. Over weeks and months, this pattern pushes A1C upward even if your diet hasn’t changed.
Chronic psychological stress works through the same pathway. Repeated exposure to poor sleep and ongoing stress gradually wears down the body’s ability to regulate blood sugar normally. Prioritizing seven to eight hours of sleep, keeping a consistent sleep schedule, and finding effective ways to manage stress (whether that’s exercise, meditation, therapy, or simply reducing obligations) are legitimate tools for lowering A1C, not just nice extras.
Using a Continuous Glucose Monitor
Continuous glucose monitors (CGMs) give you real-time feedback on how specific foods, activities, and sleep patterns affect your blood sugar. The key metric they track is “time in range,” meaning the percentage of your day spent with blood sugar between 70 and 180 mg/dL. On average, spending 70% of the day in range corresponds to an A1C of about 7%, while 50% time in range corresponds to roughly 8%.
Every 10% increase in time in range (about 2.4 extra hours per day with blood sugar in a healthy zone) translates to roughly a 0.6 point drop in A1C. For people starting with an A1C above 8%, that same 10% improvement in time in range can mean closer to a full percentage point decrease. A CGM isn’t necessary for everyone, but it’s especially useful in the early months of lifestyle changes because it shows you exactly which meals and habits spike your blood sugar, removing the guesswork.
What Medications Can Add
When lifestyle changes alone aren’t enough, medications can produce significant additional reductions. Metformin, typically the first medication prescribed, lowers A1C by about 1 to 1.5 points for most people. The newer class of injectable medications called GLP-1 receptor agonists (which includes well-known names like semaglutide and liraglutide) reduces A1C by about 1 percentage point on average for long-acting versions, with some people seeing larger drops. These medications work by helping your body release insulin more effectively after meals and slowing the rate at which food leaves your stomach, which blunts post-meal blood sugar spikes.
Medication and lifestyle changes aren’t an either-or choice. They work best together, and many people find that adding exercise and dietary changes on top of medication gets them to their target range faster than either approach alone.
Supplements With Some Evidence
Most supplements marketed for blood sugar have weak or inconsistent evidence. Two exceptions with at least some clinical support are berberine and cinnamon. A recent randomized trial found that taking 1,200 mg of berberine and 600 mg of cinnamon daily for 12 weeks significantly lowered both fasting blood sugar and A1C compared to placebo in people with type 2 diabetes. However, the reductions were modest compared to prescription medications, and supplements can interact with diabetes drugs, particularly metformin. Treat these as potential add-ons to a solid foundation of diet and exercise, not replacements for them.
A Realistic Three-Month Plan
Because A1C reflects roughly 70 days of blood sugar history, a focused three-month effort is the right timeframe for your first reassessment. During weeks one and two, concentrate on identifying and replacing your highest glycemic foods: sugary drinks, white bread, pastries, and processed snacks. Add a daily 20- to 30-minute walk. In weeks three through six, layer in resistance training two days per week, continue refining your meals toward lower GI options, and address sleep quality if it’s been poor. From weeks six through twelve, maintain your routine consistently. Consistency during this stretch matters more than perfection in any single week, because the A1C test weights recent weeks more heavily than earlier ones.
When you retest at three months, your result will reflect the full impact of your changes. People starting with an A1C above 9% often see drops of 1.5 to 2.5 points through lifestyle changes alone. Those starting between 7% and 8% might see a 0.5 to 1 point improvement. Even a 0.3 point reduction is clinically meaningful and lowers your risk of complications over time.