How to Count Carbs

Medically Reviewed by Michael Dansinger, MD on February 17, 2015
From the WebMD Archives

When you have diabetes, it’s important to balance your carbs with your medication. Have too many carbs and not enough medication and your blood sugar can soar. Too few carbs and too much medication and it can crash. Neither is good.

Counting the carbs you eat at each meal or snack can help you balance them with your medications and keep your blood sugar stable.

How Many Carbs Should You Eat in Each Meal?

Half of each meal. The U.S. Department of Agriculture recommends that you get between 45% and 65% of your calories from carbs. You could think of this as half your plate at each meal can be taken up by carbs.

Carbohydrates in grams. To be more precise, count the carbs. You can see how many grams of carbohydrates are in packaged foods by reading the nutrition facts labels. For non-packaged foods, you can look this information up online.

The Recommended Daily Allowance (RDA) for carbs is 130 grams per day. Per meal this comes to about:

  • 60-75 grams of carbohydrates per meal for men
  • 45-60 grams per meal for women

Carbohydrate choices. This can help you eyeball the number of carbs you’re going to eat once you know approximately how many carbs are in different foods. Using this method, you have a certain amount of “carb choices” you can have in a meal or snack.

  • Men can have 4 to 5 carb choices per meal
  • Women can have 3 to 4 carb choices per meal
  • Whether you’re a man or woman, snacks should be 1 or 2 carb choices

So what is a "carb choice" or serving of carbs? A carb choice is an amount of food that has about 15 grams of carbs in it.

For example, 1 slice of bread is one carb choice. But 1/4 of a large baked potato is also one carb choice. So having a whole baked potato could blow your whole carb choice budget for one meal.

You can find lists of carb choices for different foods online. You can also ask a nutritionist or diabetes instructor.

In general, it may be easiest to keep the amount of carbs you eat at each meal somewhat consistent. That way you don’t have to adjust your medications too much.

However, these are just basic ranges for the number of carbs to eat, says Dawn Sherr, a registered dietitian and spokeswoman for the American Association of Diabetes Educators.

“It’s individual to your needs and depends on what your goals are. Are you trying to lose weight? Are you trying to manage your cholesterol? Are there other issues going on with your health?” she says. “Always talk to your doctor, diabetes educator, or dietitian because they can help you adjust your carbohydrates to meet your goals.”

How Do You Know How Many Carbs Are in What You’re Eating?

Be mindfuland check your portion sizes. Knowing how many carbs you’re eating can be tricky because it depends on serving size and how many servings you eat, says Toby Smithson, a registered dietitian and spokeswoman for the Academy of Nutrition and Dietetics.

“Nowadays we can get into the habit of eating our meals really fast and eating more than we think without even realizing it. We’re used to seeing larger portions in restaurants and packaging, and what we think is one serving may actually be two or three.”

Reading labels helps, but it’s best to experiment in your own kitchen, Smithson says. “Pour a serving into a measuring cup, and then pour it onto your plate or into your bowl to see how it looks. This will help you prepare for going out to restaurants or to your friends’ or relatives’ houses.”

Another strategy is to pour what you normally eat into your bowl first, then scoop it out with a measuring cup, Sherr says. “One person’s bowl of cereal is different from another’s. One person might be used to eating one serving of cereal for breakfast while another is used to eating two.”

Keep in mind that foods like fresh fruit can vary greatly by size, Smithson says. “An apple can be anywhere from 15 to 30 or even 45 grams of carbs depending on how big it is.”

There’s an app for that. Sherr encourages you to use technology. “Many restaurants have nutrition information on their web sites, and there are phone apps for common foods,” she says, adding that these can help you plan ahead when you’re going out to eat or doing your grocery shopping.

Keep Track

Different foods will affect your blood sugar in different ways. This depends not only on the kind and amount of carbohydrates you eat and the insulin or medications you take, but other things such as how active you are, Smithson says.

“I ask clients to keep a food journal once in a while. A day or two lets us match up patterns with blood glucose readings,” Smithson says.

She suggests writing down the foods and number of carbs you eat, the insulin or medications you take, whether you exercised or had other physical activity, and your blood sugar readings.

“Try things out on yourself,” she adds. “If you see that your blood glucose is higher after eating potatoes, then you can plan for that the next time you have them by either changing your portion size or your medications.”

Smithson says that it’s important not to beat yourself up if you make a mistake counting your carbs. “It can be confusing or overwhelming at first. Remember that managing your diabetes is about more than just the food. We look at carbs because they have the most direct effect on blood glucose, but it’s not the only thing.”

All Carbs Are Not the Same

Keep in mind that the type of carbs you eat can have different effects on your blood sugar. You should also know that your body uses two types of carbs for energy: simple and complex. They affect your body a little differently.

Simple carbs are sugars. Your body digests these very quickly, so they raise your blood sugar quickly too. These include sugars that are added to processed foods such as:

  • Table sugar
  • Molasses
  • Honey
  • High-fructose corn syrup
  • Fruit juice concentrate

Fruit and milk contain simple carbohydrates naturally.

Complex carbs are starches. They take longer for your body to digest than simple carbs. So they take a little longer than simple carbs to affect your blood sugar. You’ll find them in:

  • Bread
  • Cereal
  • Rice
  • Pasta
  • Tortillas
  • Crackers
  • Pretzels
  • Beans
  • Potatoes and yams
  • Peas
  • Corn
  • Whole fruit

Fiber is also a carbohydrate, but your body doesn’t digest it, so it doesn’t affect your blood glucose.  

When you read a nutrition label, it will tell you the amount of total carbohydrates in a serving. Ask your doctor, diabetes educator, or dietitian whether it’s OK to subtract any of the fiber grams from the amount of total carbs. Some methods of carb-counting say it’s OK, while others say to go by total carbs.  

As you choose carbs, keep in mind that some are healthier than others, Sherr says. “The less processed the food is, the better. Whole grains will affect your body differently than sugary treats.” This is because processing the grains to make flour can strip away fiber and nutrients.  So for a slower increase in blood sugar, go for whole-grain foods, and whole foods like vegetables and fruits instead of processed foods or juices.

Show Sources


University of Illinois at Urbana-Champaign McKinley Health Center: “Macronutrients: the Importance of Carbohydrate, Protein, and Fat.”

CDC: “Carbohydrates.”

University of California, San Francisco: “Understanding Carbohydrates.”

Cleveland Clinic: “Carbohydrates and Blood Sugar Control for People with Diabetes.”

Dawn Sherr, MS, RD, CDE, spokesperson, American Association of Diabetes Educators.

Toby Smithson, MS, RDN, LDN, CDE, spokeswoman, Academy of Nutrition and Dietetics.

University of California, Los Angeles: “Carbohydrates.”

Joslin Diabetes Center: “How Does Fiber Affect Blood Glucose Levels?” “Carbohydrate Counting 101.”

American Diabetes Association: “Types of Carbohydrates.”

Harvard University School of Public Health: “Health Gains from Whole Grains.”

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