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How Does Food Impact Blood Glucose?
Jaclyn Konich, MPH, RD Answers by Jaclyn Konich, MPH, RD

How Does Food Impact Blood Glucose?

Whether you have recently been diagnosed with diabetes or prediabetes, or have been managing it for years, you probably know that what you eat has a big impact on your blood glucose.

Carbohydrates from food cause blood glucose to rise after meals, but that doesn’t mean you have to eliminate carbs from your meals! Carbohydrate foods are also important sources of other nutrients like fiber, vitamins, and minerals, and they provide energy for our body and our brain.

Related: Ask the Experts: All About Carbs 

There’s no set number of carbs that everyone with diabetes should eat. The eating plan and carb amount that works for you will depend on your gender, activity level, and blood glucose management plan, among other things. It will also depend on your current eating habits, food preferences, and budget.

Depending on your current eating habits, making some adjustments to your carb intake may help with blood glucose management. But, there’s no need to make drastic changes to your diet all at once, and you don’t have to eat foods you don’t like!

We encourage you to work with a Registered Dietitian (RD/RDN) or Diabetes Care and Education Specialist (CDE/CDCES) to determine what amount of carbs is right for you, and come up with a meal plan that meets your unique needs.

Tips for managing blood glucose while eating carbs

Whether you want to reduce your carb intake or not, doing one or more of these tips can help you manage your blood glucose:

  • Choose carbohydrate foods that are high in fiber, like fruits, whole grains, and beans, and pair carb foods with fat and/or protein. 

    Fiber, fat, and protein help slow digestion and absorption of glucose from carb foods, so your blood glucose will rise more slowly after a meal.

    Eating foods higher in fat and protein before eating carb foods in a meal may also help slow glucose absorption.

  • Go on a quick walk or do some other physical activity after a meal. Physical activity helps burn glucose after a meal. Even as little as 5-10 minutes can help lower blood glucose or prevent a spike in blood glucose. 

  • Eat roughly the same amount of carbs for breakfast, lunch, and dinner each day. Consistency in your eating pattern can make it easier to predict highs and lows in blood glucose, and helps medications manage blood glucose consistently. This tip is especially important if you are using insulin. 

  • Gather data! Check your blood glucose after eating different carbohydrate foods to see how they impact your blood glucose. Everyone is different, and some foods may impact blood glucose more or less in each person.

    Experiment with different combinations of food, too, to see what impact that has on your blood glucose. For example, an apple alone may raise blood glucose more than an apple paired with peanut butter, which provides fat and protein.

    Gathering this data will help you understand how your body responds to different foods so that you can make informed food choices that work for you. 

Related: Carb-Conscious Meal Makeovers

Trying to cut back on carbs? Here are some tips:

If you do want to lower your carb intake, these tips are easy ways to cut back, without sacrificing your favorite foods:

Reduce the portion size of carb foods in your meal. Cutting back on the amount of rice, pasta, or other carb foods in your meal is an easy way to reduce carbs without giving anything up.

The Diabetes Plate Method is a great visual way to manage portion sizes, without any counting or measuring. Simply limit your portion of carb foods to about one-quarter of your plate.

If a meal includes several carbohydrate foods, remove one. For example, a burrito may include rice, beans, and a tortilla. Leaving out the rice won’t impact the flavor, but it will cut down on the carbs. Or, you could ditch the tortilla and make a “burrito bowl.”

If you’ve reduced or removed carb foods from your meal, you can replace them with lower carb alternatives.

For example:

  • Replace some or all of the spaghetti in a dish with zucchini “noodles.”
  • Replace some or all of the rice in a dish with cauliflower rice.
  • Replace a carb side dish, like mashed potatoes, corn, or french fries, with a nonstarchy side, like a small salad or roasted broccoli.
  • Replace sugary drinks like soda, sweet tea, or juice with water, unsweet tea, or a sugar-free drink.

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