Diabetes Forecast

Debunking Claims About Advanced Carb Counting

By Allison Tsai and Erin Palinski-Wade, RD, CDE , ,


With all the information available on carb counting, it’s hard to decipher between truths, half-truths, and total myth. That’s why we’ve asked our experts to weigh in on a few common claims.

The Claim:

You must account for sugar alcohols and fiber when carb counting.

If you’re an advanced carb counter, there’s a good chance you’ve heard about a type of carb counting that some say can lead to more-accurate carb estimations. Whether you just count a food’s total carbohydrate or subtract fiber and sugar alcohols to get your count depends on your treatment plan. “For individuals with type 2 diabetes who are not on insulin, looking at the total carbohydrates and serving size is enough to provide a good estimate for blood glucose management,” says Jill Weisenberger, MS, RDN, CDE, author of Diabetes Weight Loss-Week by Week: A Safe, Effective Method for Losing Weight and Improving Your Health.

If you use mealtime insulin to manage diabetes, you may be interested in a more precise method of counting. “People with diabetes who adjust their insulin doses based on their carbohydrate intake may need to subtract a portion of the fiber and sugar alcohols in their foods to avoid giving themselves too much insulin and causing their blood glucose levels to go too low,” Weisenberger says.

Fiber and sugar alcohols minimally impact blood glucose, so for some people, including these in your carb count could lead to over-dosing insulin. If you find yourself going low after meals, you may want to consider subtracting the fiber grams from the total carbohydrate grams and using that as your carb total for dosing mealtime insulin. For instance, you’d consider a food with 25 grams of total carbohydrate, with 10 of those grams fiber, as having 15 grams of carbohydrate (25 – 10 = 15).

Sugar alcohols, which go by names ending in “ol,” such as sorbitol and maltitol, are only partially digested in the body, providing less of an impact on blood glucose than sugar. Because of this, you may choose to subtract the grams of sugar alcohol from the total carbohydrate. So a food with 30 grams of carbohydrate and 10 grams of sugar alcohol would be counted as 20 grams of total carb (30 – 10 = 20).

The Verdict: Taking sugar alcohols and fiber into account isn’t necessary for most people with diabetes, but it may help some mealtime insulin users get a more accurate carb count.

The Claim:

Fat and protein don’t matter when calculating an insulin dose.

When dosing your insulin for a meal, it may be helpful to take fat into account when your food has more than 10 grams, says Sacha Uelmen, RDN, CDE, director of nutrition at the American Diabetes Association. Protein isn’t so much a concern, but you will want to consider the amount of fat in your protein source and the rest of your meal if you are not getting to your target blood glucose goals, she says.

High-fat meals affect blood glucose differently than if you’re eating a balanced meal. That’s because it takes longer for the digestive muscles to break down fat. “Everything in your stomach is going to release slower,” says Uelmen. To account for this change in digestion, you may need to adjust your mealtime insulin so it peaks when your food has digested. If your dose goes into action before your meal has been digested, your blood glucose could drop.

You can work with your doctor or certified diabetes educator to adjust your insulin dose in a few ways. If you use an insulin pump, one recommendation is to program it to dose half of your insulin before the meal, and half after—what’s known as a “dual wave,” “combo,” or “extended” bolus. You’ll want to work with your diabetes educator to get the amount of insulin and timing right. For instance, if you eat pizza every Friday night, your educator may suggest programing your pump to deliver 30 percent of your typical bolus before the meal and 70 percent over the next four hours. “It’s trial and error,” Uelmen says. “But once you get one [type of food] down, it gives you a starting place for the next food.”

If you’re on multiple daily injections and experience hypoglycemia from higher fat meals, Uelmen recommends taking your insulin just after the high-fat meal. Your blood glucose might start to rise a bit before the insulin kicks in, but you’ll avoid lows. You can also take a smaller dose of insulin before the meal, followed by a larger correction dose later—just don’t forget to take that second dose.

The Verdict: When a meal has more than 10 grams of fat, you’ll want to consider your mealtime insulin dose accordingly to avoid lows after the meal.

The Claim:

Count and dose for carbs in nonstarchy vegetables.

Nonstarchy vegetables, such as broccoli, zucchini, peppers, and spinach, are high in fiber, low in carbs, and all around nutritious. When these veggies constitute most of your meals, you may have to rethink how you count carbs and dose mealtime insulin, particularly if you experience hypoglycemia often, says Uelmen. Typically, the rule is to not dose for nonstarchy vegetables. “They’re kind of free foods.”

If you dose to cover these veggies, you could experience lows: Because of nonstarchy veggies’ high fiber content, the carbohydrate does not completely break down into glucose. Instead, some of the fiber travels through your bloodstream, attaching to waste and toxins, carrying those substances out of your body through urine and bowel movements. “I like to think of fiber as a toothbrush for your insides,” says Uelmen.

If you find that certain nonstarchy vegetables increase your blood glucose, talk with your diabetes educator about adding a small amount of insulin to your mealtime dose—you still won’t need your typical insulin-to-carb ratio for those nonstarchy vegetables, she says.

The Verdict: It’s typically not necessary to count carbs for nonstarchy vegetables.

The Claim:

Diligent carb counting and insulin dosing will yield perfect blood glucose levels.

Carb counting is a very valuable tool, and it works most of the time. But even if you painstakingly calculate carbs and dose insulin, your blood glucose likely won’t be perfect all the time. That’s because stress, dehydration, exercise, and other factors could have an impact. “The more you strive for perfection, the more you’re going to end up frustrated,” Uelmen says. “It just doesn’t work that way.”

Diligence is great, and it’s important to pay attention to your body and learn how it reacts to various foods, but one high number is nothing to worry about, says Uelmen.

The Verdict: Don’t wallow over one high glucose reading. Instead, focus on your blood glucose trends.

For more fact vs. fiction, head here. We set the record straight on three nutrition claims.



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