To lower your A1c, cut sugary drinks and eat one carb serving less per meal, then move about 150 minutes a week, which lowered A1c about 0.6% in a review of 127 trials. Supplements such as psyllium or berberine come last.
Your A1c is a blood test that shows your average blood sugar over about the last 3 months, with the newest weeks counting the most (ADA Standards of Care 2026). When I say something lowers A1c about 0.5%, I mean it could move 8.0% to about 7.5%.
Every 1% matters. In the British UKPDS study, each 1% lower A1c went with about 14% fewer heart attacks and 37% fewer eye and kidney problems (UKPDS). It watched people over time, so it shows a link, not proof.
In my book, I graded dozens of foods, habits and supplements. The evidence puts them in the same order I give patients. Diet comes first, then exercise, then supplements.
The book's grades: Cutting sugary drinks, eating fewer carbs and moving about 150 minutes a week are Start here items, the top priority. Psyllium and berberine, the best-graded supplements, are PLAUSIBLE (might help).
Lifestyle and medicine work together
Some people read a page like this hoping I'll tell them to throw their pills away. I won't. Medicine has its place, and for some people it is the right tool. Nothing here replaces a medicine your doctor has prescribed. These habits add to your treatment. Never stop or change a prescribed medicine on your own.
Talk with your doctor before you change how you eat, start exercising or add a supplement. That matters most if you take insulin or certain diabetes pills called sulfonylureas (glipizide, glyburide or glimepiride). With these, fewer carbs or more movement can drop your sugar under 70 mg/dL, which is a low. If you get shaky, sweaty or confused, take 15 grams of fast sugar, such as glucose tablets, and recheck in 15 minutes (ADA Standards of Care 2026).
Some situations call for medicine first. If your A1c is over 10%, or you're very thirsty, urinating a lot or losing weight without trying, the ADA says doctors should consider insulin (ADA Standards of Care 2026). No supplement comes close to the drop you'd need.
If you want to try these habits, this is the order I'd use.
Step 1: Lower A1c with food first
You don't need a strict diet. A 10% cut in carbs you keep for five years will do more than a 40% cut you give up in March.
Cut sugary drinks first
Sugary drinks and fruit juice get the book's top harm grade, HARMFUL (clear harm), for blood sugar. In studies that followed people for years, each daily sugary drink was linked to about 18% more risk of getting type 2 diabetes (review of 17 studies).
Today: swap them for water, sparkling water, unsweetened tea or black coffee. If you drink a lot of soda, cut down over a week or two. Diet soda is a reasonable bridge.
Eat one carb serving less per meal
On about 2,000 calories a day, a 10% cut in carbs is about 50 grams a day, or roughly one carb serving less at each meal. One serving is one slice of bread or a third of a cup of cooked rice.
That's worth about 0.2% of A1c, say from 8.0% to about 7.8%. In 50 trials with 4,291 people with type 2 diabetes, each 10% cut in the share of calories from carbs lowered A1c about 0.2% at 6 months, and a 20% cut about 0.4% (review of 50 trials).
Use the plate method
Use a 9-inch plate. Fill half with non-starchy vegetables, a quarter with protein and a quarter with carb foods such as rice, bread, tortillas, beans or fruit. No counting needed.
In a trial of 419 people with type 2 diabetes, a simple plate leaflet lowered A1c 0.7% at three months and 1.44% at six months, at least as much as carb counting. Some came back later, so keep the habit going (trial).
Eat vegetables and protein first, carbs last
In 17 studies of 389 adults with type 2 diabetes, eating the carbs last lowered blood sugar 1 hour after the meal by about 43 mg/dL (2026 review). The A1c drop was small, about 0.16%, so this is mainly a spike tool. More in eat your carbs last.
Lean on beans and fiber
Beans, lentils and chickpeas are graded SUPPORTED (works) for smaller after-meal spikes when they replace other starches (review of 65 trials). The ADA asks for at least 14 grams of fiber per 1,000 calories, about 28 grams on a 2,000-calorie day (ADA Standards of Care 2026). Add fiber slowly and drink more water, or expect gas.
Step 2: How exercise lowers A1c
Muscle is the main place sugar goes after a meal. In lab tests where insulin is dripped into a vein, about 80% of the sugar cleared from the blood goes into muscle (study). Insulin works less well in type 2 diabetes, but a working muscle can still pull sugar in without waiting for insulin (study).
Muscles stay more sensitive to insulin for roughly 12 to 48 hours after a workout (review), so the ADA says not to go more than 2 days in a row without activity (ADA Standards of Care 2026).
Aim for about 150 minutes a week
A 2026 review pooled 127 trials and 8,744 people with type 2 diabetes. Most of the A1c benefit came by about 150 minutes a week of brisk walking, where A1c fell about 0.57%, say from 8.0% to about 7.4%. Past about 250 minutes, the curve leveled off (2026 review).
That's 30 minutes, 5 days a week. Brisk means you can talk in full sentences but can't sing (CDC). Start easy and add a few minutes when it gets too easy.
Walk soon after meals
In one trial, 41 adults with type 2 diabetes tried one 30-minute walk a day and, separately, a 10-minute walk after each main meal, with the same total time. The after-meal walks lowered after-meal sugar about 12%, and about 22% after dinner (trial). Start within about half an hour of eating. More in walking after meals.
Add strength training 2 to 3 days a week
More muscle means more room to store sugar. On its own, strength training lowered A1c about 0.39% to 0.50% in trials of people with type 2 diabetes (review; review). Combined with walking, it beat either one alone in 37 trials (review of 37 trials).
The best results came with 2 to 3 sessions a week, about 3 sets of 8 to 10 reps, over 12 to 16 weeks (review). Standing up from a chair 10 times is one set. Pick a load where the last couple of reps feel hard, but you could still do one or two more with good form.
Safety: if your medicines can cause lows, carry glucose tablets when you exercise. A low can show up hours later, even overnight. If you're new to exercise or have joint, heart or foot problems, ease in. A physical therapist or trainer can help you avoid injury.
Step 3: Supplements to consider for A1c
No supplement can make up for a poor diet and too little exercise, so these come last. The ADA doesn't recommend any supplement for lowering blood sugar. Some supplement numbers look about as big as exercise's, but their trials are smaller, shorter and less reliable, and unlike a walk, they can interact with your medicines. Two have the clearest A1c numbers.
Psyllium
The book's grade: PLAUSIBLE (might help). Many trials agree, but most are small. Safety badge: Generally safe.
- How much: A1c down about 0.75% in a 2024 review of 19 trials with 962 adults, for example from 8.0% to about 7.3% (2024 review).
- Skip it if you have trouble swallowing, a past bowel blockage or a slow-emptying stomach (gastroparesis), unless your doctor has cleared it.
- Dose: about 10 grams a day or more. Under 10 grams didn't clearly lower A1c. One over-the-counter label lists about 3.4 grams per rounded teaspoon (label), so 10 grams is about 3 rounded teaspoons a day in total, split before two meals. Start well below that and build up over a few weeks.
- Water: stir each dose into at least 8 ounces of water and drink it right away. Without enough water, psyllium can swell and cause choking.
- Your pills: take them at least 2 hours before or after psyllium. If you take a diabetes pill with a meal, take the psyllium at a different meal, or ask your pharmacist how to space them.
Berberine
The book's grade: PLAUSIBLE (might help). Studies keep pointing the same way, but most are small. Safety badge: Check your meds first.
- How much: A1c down about 0.6% across 37 studies with about 3,000 people with type 2 diabetes, for example from 8.0% to about 7.4% (review of 37 studies). More in berberine for blood sugar.
- Medicine interactions: berberine slows the liver system that clears many medicines from your body, so they can build up (interaction study). Show your pharmacist your full medicine list before the first pill.
- Skip it if you're pregnant, could be pregnant or are breastfeeding, and never give it to a baby. It has been linked to a harmful buildup of bilirubin in newborns (NIH).
- Dose: usually 500 mg two or three times a day, with meals (trial).
Try one at a time. Get a starting A1c, add one supplement at the studied dose, keep everything else the same and recheck in about 12 weeks. Keep it only if it helped. If you take insulin or a sulfonylurea, check your sugar more often at first. Even with steady care, an A1c around 7.5% typically moves about 0.6% either way from test to test (review of 111 studies), so don't read much into a drop under about half a point.
How to lower A1c fast, and what's realistic
Nobody can drop your A1c in a week, because it reflects about 90 days of blood sugar. Your after-meal readings can improve at the very next meal, though, and because the newest weeks count most, the ADA says a meaningful A1c change can show up in less than 120 days (ADA Standards of Care 2026).
For a realistic timeline, get a starting A1c, add one new habit about every two weeks, starting with the sugary drinks, and recheck at about 3 months. Save supplements for after that.
How much to expect depends on where you start. In exercise studies, people whose diabetes was badly out of control saw drops of about 0.7% to 1.0%, and people with prediabetes about 0.2% to 0.4% (review). And the numbers here don't simply add up.
Bottom line
Start with food. Drop the sugary drinks, trim one carb serving per meal and fill half your plate with vegetables. Then move about 150 minutes a week, with walks after meals and strength work 2 to 3 days a week. If you want more, try psyllium or berberine, one at a time. Recheck your A1c at about 3 months, and keep taking your medicines as prescribed.
Questions people ask
How can I lower my A1c naturally?
Cut sugary drinks, eat fewer carbs and move about 150 minutes a week. In trials, that much brisk walking lowered A1c about 0.6%, and each 10% cut in carbs about 0.2%.
How long does it take to lower A1c?
Plan on about 3 months, since A1c reflects about the last 90 days. Recent weeks count most, so your next test can show progress.
What foods lower A1c?
No single food does it, and your overall pattern matters most. Mediterranean eating (vegetables, beans, whole grains, fish, nuts and olive oil) is graded SUPPORTED and lowered A1c about 0.3% in 11 trials (review). Beans and lentils in place of other starches are SUPPORTED for smaller spikes.
Can I lower my A1c without medication?
Keep taking any medicine you're prescribed, and never stop one on your own to test whether you still need it. Some people bring their A1c below the diabetes range with lifestyle alone, mostly early on and with weight loss. In the DiRECT trial, 46% of people with recent type 2 diabetes reached an A1c under 6.5% without diabetes medicine at one year, on a closely supervised diet (DiRECT). That is still management, and the number drifts back up if the habits stop.
What else the book grades, from shakes to potatoes
Your A1c by the Numbers grades dozens of foods, habits and supplements, each with a real number. Three that surprise people:
- Meal-replacement shakes, as part of a planned weight-loss diet, are graded SUPPORTED. They lowered A1c about 0.46% in 17 trials (review).
- Baked, boiled and mashed potatoes are graded HARMFUL for blood sugar as a regular food. Boiled red potatoes raised blood sugar faster than white bread (a glycemic index of about 89 versus about 75) (study).
- Cinnamon pills are graded UNLIKELY TO HELP. A 2023 review found no real effect on A1c (review).
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