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Carbohydrates and Diabetes

What Are Carbohydrates?

Carbohydrates (carbs) are one of the three big nutrients that make up food. The others are protein and fat. Carbs give your cells energy. People with diabetes need to know about carbs because all carbs raise blood sugar levels.

Sugar, Starch, and Fiber Are All Carbs

Carbohydrates come in three forms: sugar, starch, and fiber. Getting the right balance of sugars, starches, and fiber is key to keeping blood sugars in a healthy range. It helps to know that:

  • Added sugars raise the blood sugar quickly. Foods with added sugar (like cake, cookies, and soft drinks) make blood sugars spike. You might see sugar, corn syrup, dextrose, sucrose, or fructose listed on the food label. Foods that naturally contain sugar (like fresh fruits, milk, and Greek yogurt) don’t cause blood sugar to rise as quickly as added sugars and are more nutritious.
  • Some starches raise the blood sugar slowly. In general, starches that are less processed tend to raise the blood sugar more slowly. These include foods like brown rice, lentils, and oatmeal. Foods that are processed a lot, like white rice and white bread, raise the blood sugar quickly.
  • Fiber helps slow down sugar absorption. A diet with plenty of fiber can help people with diabetes keep blood sugar levels in a healthy range. The fiber in foods helps carbs break into sugar slower. So there's less of a peak when blood sugar spikes. Good sources are whole fruits and vegetables, nuts and seeds, and whole grains. Fiber also helps you feel full, and it keeps the digestive system running smoothly.

What Happens When You Eat Carbs?

After you eat, your body breaks down carbs into glucose (sugar). Glucose gives your cells energy. The glucose moves into the bloodstream, and your blood sugar level rises. As it does, the pancreas releases the hormone insulin. Your body needs insulin to get glucose into cells.

People with diabetes have a problem with insulin, so glucose has a hard time getting into the cells:

  • For people with type 1 diabetes, the pancreas doesn’t make insulin.
  • For people with type 2 diabetes, the pancreas makes insulin, but the body doesn’t use it as it should.

In both types of diabetes, when glucose can't get into the cells, the blood sugar level gets too high. High blood sugar levels can make people sick and are unhealthy.

Carbs and Your Blood Sugar

Carbohydrates are an important part of a healthy diet. Everyone needs carbs, including people with diabetes. Carbs provide the fuel you need to get through the day. Making smart choices when it comes to carbs and following your diabetes care plan can help keep blood sugars under control. Use these tips to guide you:

  • Choose healthy carbs. Get most carbs from whole grains, vegetables, and fresh fruit. These foods are good because they also contain fiber, vitamins, and other nutrients.
  • Limit highly processed foods and foods with added sugar. These foods and drinks can make it hard to keep blood sugar levels in the healthy range.  Avoid all beverages with carbs (except milk). They provide no nutritional value and cause blood sugar levels to spike. These should only be used for treating a low blood sugar.
  • Count carbs. Read food labels to help you. At a restaurant, ask your server for nutrition information or check for information online.
  • Weigh and measure Use a scale and measuring cups to get an accurate carb count. This helps you match insulin doses to the carbs you eat.
  • Stay active every day. Regular exercise makes insulin work better and can help keep blood sugar in the healthy range.

Understanding how carbs fit into a balanced diet makes it easier to keep your blood sugar in a healthy range. If you need help counting carbs or have questions about what to eat, talk to the dietitian on your care team.

Reviewed by: Cheryl Patterson, RD, LDN, CDCES
Date Reviewed: Jan 1, 2022

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