Foods, Prediabetes

Best and Worst Carbs for Prediabetes

If you have prediabetes, carbs have the greatest direct effect on blood sugar. But which carbs are the best, and which carbs are the worst for prediabetes?
Carbs to avoid with prediabetes
Natalie Stein

Exercise, Fitness & Nutrition Expert | Lark Health

Having prediabetes means being at higher risk for developing type 2 diabetes within a few years. With prediabetes or type 2 diabetes, your body has trouble metabolizing carbohydrates properly from the foods and beverages you consume. The result is higher than normal levels of blood sugar.

If you have prediabetes, what you eat can affect your risk for developing diabetes. Carbohydrates have the greatest direct effect on blood sugar, and the American Diabetes Association suggests consuming a “moderately” low-carbohydrate diet can help manage blood sugar.

The quality, or type, of carbohydrates also matters, according to the American Diabetes Association.

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Types of Carbohydrates

Sugars and starches are types of carbohydrates that can affect blood sugar. The Harvard School of Public Health explains that carbohydrate-containing foods that spike your blood sugar quickly and to a high level are considered high-glycemic, and those which have a more moderate effect are lower-glycemic. 

You cannot always predict which carbs are high or low-glycemic, but these are some general patterns.

These May Increase Glycemic Index These May Decrease Glycemic Index
  • Less fiber
  • More sugar
  • More processing
  • More cooking (such as long-cooked pasta compared to barely al dente)
  • More fiber
  • More fat or protein
  • Less processing (for example, whole compared to refined grain, or fresh compared to canned vegetable)
  • Raw compared to cooked

Often, it is a good idea to choose lower-glycemic foods instead of higher-glycemic foods when choosing carbohydrates if you have prediabetes or diabetes, but other factors include serving size and nutrient content. These are some of the best and worst carbs to choose if you have prediabetes.

5 Best Carbs for Prediabetes

These are some high-fiber, high-nutrient carbohydrates that may help with weight loss or improve insulin resistance.


Oats are whole grains, which have been linked to lower risk for type 2 diabetes. An analysis of three studies that was published in British Medical Journal found that people who had the highest amount of whole grains, or about 1.9 servings per day, were 29% less likely to be diagnosed with diabetes when compared to people who ate almost no whole grains. Oats in particular have compounds such as phytosterols and soluble fiber that can lower cholesterol, according to the Linus Pauling Institute. Wheat bran cereals, whole-grain bread and pasta, brown rice, and popcorn are other whole grain choices. 

Sweet potatoes

Though it is a starchy vegetable, sweet potatoes may be a good carb when talking about diabetes prevention. A study in the Journal of Nutrition found a lower risk of developing diabetes among people who ate the highest levels of vegetables such as sweet potatoes and carrots, which are both high in fiber, potassium, and beta-carotene. Sweet potatoes make great baked “fries” with parmesan cheese and olive oil, and they can go into soups, be baked and served with toppings such as chives, broccoli, and cottage cheese, or be served in breakfast hash with eggs or tofu. 


If you are worried about consuming fruit because of its high sugar content, oranges are a good place to start. The Harvard School of Public Health says that they have only a small effect on your blood sugar, likely because of their fiber and acid content. Oranges and other citrus fruits are also packed with vitamin C, which has been linked to lower risk for diabetes according to research published in Archives of Internal Medicine. These portable and convenient fruits are good on their own, in salads, or even cooked into salsa to serve with portobello mushrooms or fish.


Often touted for their high content of plant-based protein, lentils are also packed with fiber, potassium, and magnesium. A review article published in Clinical Diabetes discusses the possible protective effect of consuming legumes, including lentils, split peas, and beans, against developing diabetes. They may also protect against certain types of cancer and heart disease. Lentil soup, veggie burgers, and salads are good dishes for using lentils.


How often does it happen that one of the best-tasting foods is also one of the healthiest? Strawberries are an example that it can happen! They have less than half the amount of carbs as some kinds of fruit, are lower glycemic, and are high in fiber and vitamin C, not to mention phytonutrients such as ellagic acid and quercetin. Along with devouring them plain, strawberries are great in oatmeal, cold cereal, yogurt, and cottage cheese, as well as in salads or cooked into pancakes. 

5 Worst Carbs

Some carbs may raise the risk of diabetes by contributing to weight gain and/or raising blood sugar levels and insulin resistance. These are some carbs to limit on a prediabetes diet.

French Fries

Potato consumption is linked to higher risk for diabetes, with those consuming the most potatoes having a 14% greater risk, and those consuming the most french fries having a 21% greater risk, compared to those eating the least, according to research in American Journal of Clinical Nutrition. Potatoes are high-glycemic and are often consumed with less-healthy foods, such as butter in mashed potatoes, and French fries contain excess fats. Baked sweet potato, zucchini, or carrot fries are possible alternatives at home, while side salads and baby carrots are commonly available sides at burger joints.

Soft Drinks

They are not even food, but they can sure do a lot of damage. Sugar-sweetened beverages account for 35% of total sugar consumption in the US, including 16% from soft drinks, 11% from coffee and tea, and 5% from fruit drinks, according to the Dietary Guidelines. Research studies have convincingly shown links between sugar-sweetened beverages and diabetes risk, according to research in the Journal of the Endocrine Society

Kids’ Breakfast Cereal

It is not that breakfast cereal is so bad. It is not. In fact, cereal eaters can have a higher intake of vitamins and minerals, according to research in Advances in Nutrition. Still, why eat sugary, refined breakfast cereals when low-sugar, whole-grain options are available on the same shelf? Cereals targeted to kids are among the worst offenders, but many cereals for grown-ups are loaded with added sugars such as sugar, honey, and corn syrup. Shredded wheat, regular Cheerios, puffed rice, and plain oatmeal are healthy, convenient, and satisfying alternatives, and adding fruit can make them sweeter.

White Rice

As healthy as brown rice and other whole grains can be, white rice and other refined grains can be harmful when it comes to diabetes risk. They are high in starch and low in fiber, and they often come in oversized portions, which makes them even worse for blood sugar. It is easy to substitute whole grains for refined ones. Brown rice can go into the same dishes as white rice, and it is often available at Asian restaurants as an alternative to white rice.

Baked Goods

Many baked goods are not only high in added sugar and refined flour, but they also contain unhealthy or excess fats. Brownies, cookies, pies, cakes, and muffins are just a few examples of such high-calorie goodies. If possible, it is best to bake with less sugar and fat, while substituting whole-grain flour for some or all of the white flour in a recipe. If you are purchasing your baked goods rather than baking them, having a smaller serving size, limiting yourself to just a few days a week, and using fruit to satisfy a sweet tooth can make a big difference.

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The great news is that carbs are not off limits if you are working to lose weight and eat healthy to prevent diabetes. With a few smart choices, it’s still okay to have cereal for breakfast, a sandwich for lunch, pasta for dinner, and a sweet something later. Just look for whole, less-processed choices, such as whole grains and products without added sugars!

All these good and bad carbs may seem like a lot to worry about, but it is simple when you have a personal coach in your pocket. Lark Diabetes Prevention Program offers coaching for eating well and making other healthy changes with prediabetes, and you may be eligible for the program through your health insurance or employer!