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Home > Wellness > Health Library > Diabetes: Counting Carbs if You Use Insulin
Carbohydrate, or carb, counting is an important
skill to learn when you have
diabetes. Carb counting helps you keep tight control of your blood sugar (glucose) level.
It also gives you the flexibility to eat what you
want. This can help you feel more in control and confident when managing your
count carb grams at a meal, you need to know how many carbs are
in each type of food you eat. This includes all food, whether it is a slice of bread, a bowl of lettuce, or a
spoonful of salad dressing. Most packaged foods have
labels that tell you how many total carbs are in one serving.
Carbohydrate guides can help too. You can get these from diabetes educators and the American
To find out how many carbs are in food that
is not packaged, you will need to know standard portions of
carbohydrate foods. Each
serving size or standard portion has about 15 grams of
By using the number of grams of carbs in
a meal, you can figure out how much insulin to take. This is based on your
personal insulin-to-carbohydrate ratio.
For example: Your doctor may advise you to take 1 unit of rapid-acting
insulin for every 10 to 15 grams of carbs you eat. So if your meal
has 50 grams of carbs and your doctor says you need 1
unit of insulin for every 10 grams of carbs, you would need 5 units of
insulin to keep your post-meal blood sugar from rising above your target
Your insulin-to-carbohydrate ratio may change over time. In
some people it will change from one meal to the next. You might take 1 unit of
insulin for every 10 grams of carbs for lunch but take 1 unit for every
15 grams at dinner.
Keep these tips in mind when counting carbs:
When you keep track of what you eat and you test your blood
sugar after meals and exercise, you can figure out what effect
protein, fat, fiber, and exercise have on the amount of insulin you need.
To count carbs and eat a balanced diet:
Other Works Consulted
American Diabetes Association (2013). Nutrition therapy recommendations for the management of adults with diabetes. Diabetes Care, 36(11): 3821–3842. DOI: 10.2337/dc13-2042. Accessed December 5, 2013.
American Diabetes Association (2014). Standards of medical care in diabetes—2014. Diabetes Care, 37(Suppl 1): S14–S80. DOI: 10.2337/dc14-S014. Accessed January 7, 2014.
Campbell AP, Beaser RS (2010). Medical nutrition therapy. In RS Beaser, ed., Joslin's Diabetes Deskbook: A Guide for Primary Care Providers, 2nd ed., pp. 91–136. Boston: Joslin Diabetes Center.
Franz MJ (2012). Medical nutrition therapy for diabetes mellitus and hypoglycemia of nondiabetic origin. In LK Mahan et al., eds., Krause's Food and the Nutrition Care Process, 13th ed., pp. 675–710. St Louis: Saunders.
Current as of:
June 4, 2014
E. Gregory Thompson, MD - Internal Medicine & Rhonda O'Brien, MS, RD, CDE - Certified Diabetes Educator
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