Best Diet for Prediabetes: Foods to Eat & Avoid

In a room of 10 adults, more than three are likely to have prediabetes, and many may not even know it. Prediabetes is a type of health warning that your blood sugars are consistently higher than the normal range but not too high to be diagnosed with type 2 diabetes.

Knowing you have prediabetes is a good thing. Prediabetes can often be reversible. Making lifestyle changes, including changes to your diet and getting to a healthy weight, can help balance blood sugars and lower your risk of developing type 2 diabetes.

Understanding prediabetes

Blood sugar, also called blood glucose, is the primary and most readily available energy source for your cells. Insulin, a hormone, acts like a key that opens the door to allow sugar from the blood to enter the cell. In prediabetes, insulin production slowly declines and the cells gradually become insulin resistant, so the key no longer works properly, making the lock harder to open, leading to higher blood sugar levels.

Doctors use hemoglobin A1C (A1C) to check for prediabetes and diabetes. A1C is a blood test that measures the percentage of your average blood sugar over the past three months:

Too much sugar in the blood means the cells aren’t getting the energy they need, making you tired and hungry, among other symptoms. The body responds by increasing the production of insulin to bring blood sugar back to a normal range. This stresses the insulin-producing cells, lowering insulin production and making it harder to bring down blood sugar.

Over time, the excess glucose in the blood may contribute to damaging the blood vessels, certain organs, and nerves, leading to an increased risk of heart disease, vision and nerve problems, and kidney issues.

Diet principles for prediabetes

Scientific evidence suggests that lifestyle modifications may be one of the effective tools for potentially reversing prediabetes and preventing type 2 diabetes, and diet changes are a key factor.

One of the most well-known dietary approaches supporting overall health, thus often associated with blood sugar regulation, is the Mediterranean diet, which prioritizes fruits, vegetables, whole grains, lean proteins, and healthy fats.

In my practice, working as a registered dietitian and nutritionist for over 25 years, folks mistakenly believe they need to give up their favorite foods or follow extreme diets when they have prediabetes. However, restrictive diets with a list of ‘good’ and ‘bad’ foods are hard to follow long-term. These diets and eating practices may also wreak havoc on blood sugar, causing hypoglycemic episodes that make you dizzy, shaky, and irritable or cause more serious health disturbances.

I often recommend managing prediabetes by developing healthy eating habits that include a variety of nutritious foods and can be followed for life. A diet for prediabetes is about balance, portion control, and making smarter choices.

According to a 2024 review study published in Food Agriculture and Immunology, the Mediterranean diet supports proper fasting blood sugar levels and insulin sensitivity in people with prediabetes.

Foods to emphasize

The journey to better health includes a colorful diet filled with nutrient-dense foods that may help manage blood sugar levels and weight as well as support your overall sense of well-being.

Non-starchy vegetables

Fill half your plate with colorful vegetables like broccoli, kale, leafy greens, carrots, and bell peppers. Rich in fiber, vitamins, minerals, and antioxidants, non-starchy vegetables help curb hunger and contribute to the management of blood sugar levels.

Complex carbohydrates

Carbohydrates aren’t the enemy, as choosing the right ones is key. When you have prediabetes, you may want to include complex carbohydrates that are high in fiber, vitamins, and minerals.

This means whole grains like steel-cut or rolled oats, barley, quinoa, and brown rice, along with whole-wheat bread and pasta.

While complex carbohydrate inclusion is recommended for long-term overall health support and blood sugar control, portion size does matter. Eating too many carbs at once may make blood sugar management more challenging. Mind your portions of carbohydrates, keeping in mind that a half-cup of cooked grains, one slice of whole-wheat bread, and three cups of air-popped popcorn are equal to one serving.

Consistency helps. So, try eating about the same amount of carbohydrates at each meal around the same time. Focus on smaller but more frequent meals throughout the day.

Lean proteins

Protein may help maintain muscle mass while working toward weight loss goals. Fish, skinless poultry, occasional lean red meat, eggs, low-fat dairy products, legumes, nuts, and seeds are good choices, providing protein without excessive saturated fat intake.

Fatty fish like salmon, tuna, and mackerel are also a great addition to most people's meal plans. Fatty fish are rich in essential fatty omega-3 fatty acids that may support heart health among other benefits.

Fruits

I often emphasize to my clients not to fall victim to the misconceptions surrounding fruit. Fruit is a source of sugar, but it comes with so many good-for-you nutrients like fiber, vitamin C, potassium, and antioxidants. That said, be mindful of fruit portions: one small piece of fruit, 1/2 cup of cut fruit, is equal to about one portion, and 2 tablespoons of unsweetened dried fruit. Always monitor your blood glucose to see what portion sizes and fruits are suitable for your individual case.

Berries, citrus fruit, apples, melons, and unripe or slightly green bananas can all be additions to your diet. However, take it easy with 100% fruit juice as it may cause spikes in blood sugar, and avoid dried fruit with added sugar.

Pair fruits with a protein or fat source to help manage blood sugar levels better, such as apple slices with peanut butter or strawberries and Greek yogurt.

Healthy fats

Nuts, seeds, and avocados are considered healthy fat sources to include in a balanced diet for prediabetes. Olive oil is also commonly used in the Mediterranean diet. It’s rich in monounsaturated fats and vitamin E, which may play a role in multiple body functions supporting heart and overall health.

Foods to limit or avoid

Limiting foods that may affect blood sugar levels is also recommended when trying to manage prediabetes and prevent it from turning into type 2 diabetes.

Sugary drinks

Sugary drinks may cause rapid spikes and drops in blood sugar levels and are associated with an increased risk of prediabetes. People who drink two or more sugary drinks per day are 1.3 times more likely to develop prediabetes, according to a population health study published in the Journal of Nutrition.

While an occasional drink may not significantly impact health long-term, including such drinks regularly may contribute to poorer prediabetes management. Try to limit your intake of regular soda, sugar-sweetened juice, sugary coffee drinks, and other high-sugar beverages to better control blood sugar levels.

Added sugar

Sugar is hidden in many processed foods, even those not sweet like tomato sauce and salad dressing. Added sugar packs in calories and offers very little nutritional value.

In addition to limiting sweets like candy, cookies, and cake, read the ingredients list on the Nutrition Facts label and avoid or limit those that list sugar (high fructose corn syrup, molasses, honey, caramel, juice) as one of the first three ingredients.

Remember, you do not need to completely give up certain foods. Instead, look for alternatives that align better with your overall health goals and personal preferences.

Refined carbohydrates

White bread, regular pasta, and snack foods like pretzels and chips are considered refined carb sources that may be digested quickly, causing blood sugar spikes and crashes. Swap out your usual refined carb (white bread) with whole grains (whole wheat bread).

Saturated and trans fats

Generally, it is recommended to limit saturated and trans fats as much as possible, as they have potential associations with an increase in the risk of heart disease long term. This means curbing the amount of fatty red meat, butter, bacon, and baked goods on your meal plan.

Meal planning strategies

Eating with prediabetes doesn’t have to be complicated. There are a couple of methods that can help you create healthy meals for better blood sugar and weight management.

Meal planning strategies for prediabetes include:

The plate method

The plate method is a simple strategy I often use when helping clients create balanced meals. It involves dividing your plate into sections, filling half the plate with non-starchy vegetables, one quarter with whole grains, and the other quarter with lean proteins. I like this method because it doesn’t require counting nutrients or calories or measuring each ingredient.

For example, roasted vegetables as the star of your plate with a spoon or two of quinoa, prepared with fresh herbs and spices, and a 3–4-ounce serving of roasted salmon. Round out the meal with a cup of fresh-cut fruits.

Glycemic index and glycemic load

The glycemic index is another tool we use when helping people with prediabetes and diabetes gain control over their blood sugar. The glycemic index rates carbohydrate-containing foods by how quickly they affect blood sugar levels.

Foods with a high glycemic index (white bread and white sugar) digest quickly, causing a rapid increase in blood sugar, while low glycemic foods (oats and apples) digest slowly, keeping blood sugar steady and even.

However, the glycemic index doesn’t take portion size into consideration. The glycemic load considers the GI of a food as well as the amount of carbs in a serving when looking at how it affects blood sugar. This method provides a more accurate picture of how high-carb foods affect blood sugar based on standard servings. For example, watermelon has a high glycemic index but a low glycemic load because of its low carb content per serving.

Keeping your carb intake in check can help balance blood sugar. But pairing it with foods high in fiber, protein, or fat may help, too, by slowing digestion.

Eating mixed meals and snacks (carbs with protein or fat) also helps keep hunger in check.

Lifestyle adjustments

Diet is one piece of the lifestyle changes that benefit people with prediabetes. Exercise, weight loss, and sleep count too.

Exercise

The Centers for Disease Control and Prevention recommend adults get 30 minutes of moderate-intensity exercise (bike ride, brisk walk, low-impact aerobics) five days a week. You should also include two days of strength training, such as lifting weights, body resistance exercises, or yoga.

Regular exercise may play a role in improving insulin resistance and blood sugar control.

Weight loss

Overweight and obesity are risk factors for prediabetes and type 2 diabetes. Losing weight, even as little as 5% of your current weight, can make meaningful improvements in blood sugar and insulin levels.

Eating balanced meals and getting regular exercise are essential parts of a weight management program.

Getting quality sleep

Studies show an association between poor sleep and prediabetes. Improving the quality and amount of sleep you get, aiming for 7–9 hours a night, may help manage and reverse prediabetes.

Success stories and research

Type 2 diabetes is a major public health concern. Taking steps to prevent the onset of diabetes benefits individual and public health.

The Diabetes Prevention Program (DPP), funded by the National Institutes of Health (NIH), found that lifestyle interventions can delay or prevent type 2 diabetes for up to 15 years.

Results from these studies also show that lifestyle interventions lowered the risk of nerve damage, kidney disease, and cardiovascular problems.

Final thoughts

Prediabetes may not cause obvious symptoms, but knowing about it gives you a chance to take action and potentially prevent your condition from turning into type 2 diabetes. Prediabetes is often reversible, and you can improve long-term health with diet and lifestyle changes.

Talk to your doctor or consult with a registered dietitian for individualized guidance on how to eat with prediabetes for better health now and in the future.