If you are living with diabetes, you have likely encountered the phrase “carb counting.” This means tracking the amount of carbs you consume throughout the day and setting a limit for your maximum amount of carbs to eat in each meal.

Carb counting is used religiously by many people with type 1 diabetes to set the appropriate insulin doses for the food they eat. Combined with the right balance of physical activity and medicine, carb counting can help keep your blood glucose levels in your target range, according to the American Diabetes Association (ADA). While the concept may be simple, there are many factors to consider if you want to carb count properly.

First, you should know that carbohydrates in foods are measured in grams (g). One “carb serving” is the amount of a food that contains 15 grams of carbohydrates.

Here are some average carb counts for some common foods:

• Six ounces of Greek, nonfat yogurt: 6 grams

• One large slice white bread: 15 grams

• Apple: 25 grams

• Baked potato: 63 grams

Dairy products, fruit, grains, legumes, starchy vegetables, and sugary sweets are the food groups where you will find the most carbs.

Women with diabetes are often advised to eat no more than three carb servings per meal, or 45 grams of carbs; men, no more than four carb servings, or 60 grams of carbs, per meal. You may need more or fewer carbs depending on how you manage your diabetes. The ADA suggests working with your healthcare team to figure out the right amount for you based on your individual needs. A registered dietitian or a Certified Diabetes Educator are valuable resources.

Why count?

Carb counting can help keep your blood glucose levels close to normal, according to the National Institute of Diabetes and Digestive and Kidney Diseases. Keeping your blood glucose levels as close to normal as possible may help you:

• Stay healthy longer

• Prevent or delay diabetes problems such as kidney disease, blindness, nerve damage, and blood vessel disease

• Feel better and have more energy

Once you learn how to count carbs, you’ll find it easier to fit a wide variety of foods into your meal plan, including combination foods such as those in frozen dinners, according to Joslin Diabetes Center.

Many people find carb counting to be much easier than using a more traditional exchange meal plan.

Simple and complex carbs

You should also be aware of the different types of carbs and how they affect your body.
Simple carbs are sugars that your body digests very quickly. These include:

• Table sugar

• Molasses

• Honey

• High-fructose corn syrup

• Fruit juice concentrate

Simple carbs are mostly found in processed foods. Fruit and milk contain simple carbs naturally.

Complex carbs are starches. They take longer for your body to digest, and they take longer to affect your blood sugar. Complex carbs can be found in whole-grain foods. Look for whole-grain bread, cereal, and tortillas, brown rice, and other whole-grain foods.

So, for a slower increase in blood sugar, aim to eat whole-grain foods and whole foods like vegetables and fruits instead of processed foods or juices.

Okay, where do I start?

In order for your carb counting to be effective, it is critical that you understand food labels. Packaged foods have nutrition labels that can help you understand their carb content. When reading food labels:

• Identify the total carbohydrate count, not just sugar. If you look only at the sugar number, you may end up overeating foods such as grains that have no natural or added sugar but do contain a lot of carbs, according to the ADA.

• Pay attention to the serving size. A can of soup may say it contains 30 grams of carbs per serving, but if the number of servings per can is two, then you are actually consuming 60 grams of carbs if you eat the whole can.

Know that sugar-free doesn’t mean carbohydrate-free. Always remember to check the label for the grams of carbs.

How to estimate carbs without nutrition facts

You could start by estimating portion sizes using the portion conversion method. Portion conversion involves estimating the volume of a serving of food by comparing it to a common object such as your fist, a soft drink can, or a milk carton, and then converting the volume into a carbohydrate count based on the typical carbohydrate content for a known amount of that type of food, according to Diabetes Self-Management.

For example, you might know that one cup of cooked pasta contains about 40 grams of carbohydrate. You estimate that the portion of pasta you've been given is 1 1/2 cups by visually comparing the amount of pasta on your plate to a 12-ounce soft drink can. You then do the math (40 grams x 1 1/2 cups) to determine that eating what's on your plate would mean consuming 60 grams of carbohydrates.

If you want a more precise way to count carbs without a food label, you can use carbohydrate factors. This technique involves weighing a portion of food on a scale and then multiplying the weight of the food (in grams) by its carbohydrate factor (which represents the percentage of the food’s weight that is carbohydrate). Doing so will produce a fairly precise carbohydrate count for that portion of food.

For example, apples have a carbohydrate factor of 0.13, which means that 13 percent of an average apple’s weight is carbohydrate. If an apple weighs 120 grams, the carbohydrate count is 120 x 0.13, or 15.6 grams.

Condensed lists of carbohydrate factors can be found in several books, including "The Ultimate Guide to Accurate Carbohydrate Counting" and "Pumping Insulin."

Technology may be your best friend when it comes to keeping track of those carbs. Many restaurants have nutrition information on their websites, and there are phone apps, such as Daily Carb, to help with your carb counting. Pen and paper work, too. You could keep a food journal and record the foods and the number of carbs you ate, plus other information such as the insulin or medications you took, your physical activity, and your blood sugar readings.

If you want to have a pocket guide that you can easily carry along with you, the ADA offers two: The Pocket Guide to Diabetic Exchanges (American Diabetes Association, March 1998) and the Fast Facts Series Carb Counting Made Easy for People with Diabetes (American Diabetes Association, 2002). Both offer 64 pages of extremely portable and useful information. They can be purchased online through Amazon or at a book store like Barnes & Noble.

Do you practice carb counting? Share your tips and experiences below.

Other tips in this series:

Tip 1: How to Recognize a Carb

Tip 2: There Really ARE Good and Bad Carbs

Tip 3: How to Avoid Carb Overload

Tip 5: What a Nutritionist Can Do for You