Carb Counting

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Last week we talked about two types of diabetes meal planning tools: the exchange system and the plate method. While both of these approaches can work well, today, more and more people with diabetes are turning to carbohydrate counting.

Carbohydrate, or “carb”, counting, really isn’t all that new. In fact, Dr. Elliott Joslin taught carb counting to his patients back in the early part of the 20th Century: “In teaching patients their diet,” he said, “I lay emphasis first on carbohydrate values, and teach to a few only the values for protein and fat.” Patients who came to Joslin Clinic in those days were taught by Dr. Joslin himself, and today, the walls of Joslin Diabetes Center are lined with pictures of folks from that period sitting in a classroom with gram scales in front of them for the purpose of weighing their food. Since those days, many aspects of diabetes care have changed for the better, but carb counting has made a comeback as an effective yet simple approach to help people better manage their diabetes.

There are actually two types of carb counting. The first type, often called basic or consistent carb counting (or, as one of the doctors at Joslin likes to say, “CC”), is usually what most people with diabetes learn about these days. Basic carb counting isn’t a diet, but rather a tool to help you better plan meals and learn how your food choices affect your blood glucose levels.

As you may know, most of the carbohydrate we eat turns to glucose (sugar) during digestion. Our bodies then use this glucose for energy. Let’s review the types of foods that contain carbohydrate:

  • Bread, pasta, cereals, rice
  • Starchy vegetables (corn, peas, potatoes, lima beans)
  • Fruit and fruit juices
  • Milk and yogurt
  • Sweets and desserts
  • (Non-starchy vegetables, such as broccoli, green beans, and carrots have a little carb, but not enough to affect blood glucose levels unless you eat large amounts.)

    Many people “count” carbs using grams. One carb choice, or serving, is the amount of food that contains 15 grams of carbohydrate. Whether you eat 15 grams of carb from a piece of bread or 15 grams of carb from a cookie, the effect on your blood glucose level is about the same. (It’s a common misconception that eating sweet foods causes your blood glucose level to climb higher than if you eat a starchy food.) You can learn how much carbohydrate is in your foods by reading food labels for serving size and total carbohydrate, as well as using a carb counting book that you can buy in any bookstore.

    The goal with basic carb counting is to aim to eat a consistent amount of carbohydrate at your meals on a day-to-day basis. If you eat more carbohydrate than usual at a meal, for example, you’ll probably have a high glucose level later on. Eating a certain amount of carbohydrate at meals, along with getting regular physical activity and taking your diabetes medicine as prescribed, is an effective way of controlling blood glucose levels.

    How do you know how much carb you should aim for at your meals? A dietitian is the best person to help answer this. A dietitian takes into account your medication, food likes and dislikes, eating schedule, weight goals and overall diabetes control to come up with a carb amount that’s best for you. If you’re interested in trying carb counting, you might aim for about 45 to 60 grams of carbohydrate (or three to four carbohyrate choices) at each meal until you meet with a dietitian. On reviewing your individual needs, the dietitian may recommend eating more or less carbohydrate.

    The next type of carb counting is really more like the next “level” of carb counting. Sometimes it’s called advanced carb counting, although it has nothing to do with how smart you are! Advanced carb counting is a very flexible way of meal planning that can be used by people who take fast-acting insulin (lispro, aspart, glulisine or Regular) before meals, whether by injection or via an insulin pump (you can’t do advanced carb counting if you take only diabetes pills or long-acting insulin). Here’s how it works: Right before you eat a meal, you figure out how much carbohydrate you’ll be eating. Then, using something called an insulin-to-carb ratio, you calculate how much insulin you need to take to “cover” the carbohydrate in your meal. Let’s say you have an insulin-to-carb ratio of 1:15. This means that you need to take 1 unit of your fast-acting insulin to cover every 15 grams of carb you eat. So, if you plan to eat 45 grams of carb at your meal, how much insulin would you need? If you guessed 3 units, you’re right! Pretty easy to do!

    Of course, you need to keep a few things in mind. First, your health-care team (usually your dietitian) should help you figure out your own insulin-to-carb ratio. Ratios vary from person to person, and you may even need different ratios for different meals. Second, be prepared to keep food records and check your blood glucose levels after meals for a while to make sure your ratio is correct. Third, if your blood glucose level is too high before a meal, you need to take extra insulin, along with the insulin to cover your carbs. This extra insulin is called a correctional dose and also needs to be calculated with the help of your health-care team. Finally, while advanced carb counting really gives you the flexibility of eating as much or as little carb as you want while still maintaining good diabetes control, don’t forget that you still want to eat a variety of foods and not load up on empty calories found in desserts and snack foods. Also, it’s not uncommon for people to gain weight when they start adjusting their insulin for their food intake. If you’re trying to lose or maintain your weight, you still may want to aim for a certain amount of carb at your meals, along with keeping portions of protein and fat foods in control, too.

    Carb counting is another meal planning tool that can help you manage your diabetes. Many people with diabetes find that carb counting helps them eat more like a person without diabetes because it’s more flexible than other meal planning methods. If you think you’d like to try this approach, make an appointment with a dietitian to learn more about how carb counting can work for you.

    Want to learn more about carbohydrate counting? Read “Counting Carbohydrates Like a Pro” and “Carbohydrate Counting, Glycemic Index, and Glycemic Load: Putting Them All Together.”

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