- ACRONYMS AND DEFINITIONS
- ADA - American Diabetes Assoc
- Carb - carbohydrate
- CC - carbohydrate counting
- FDA - U.S. Food and Drug Administration
- USDA - United States Department of Agriculture
- DEFINITION OF CARBOHYDRATE COUNTING
- Carbohydrate counting
- Of the 3 macronutrients (protein, fat, carbohydrate), carbohydrates have the most direct effect on blood sugar levels
- Different types of carbohydrates (ex. sugars, fiber, sugar alcohols) affect blood sugars in different ways
- Carbohydrate counting is a method of determining the amount of carbohydrates that will be consumed in a meal while taking into account the varying effects different carbohydrates have on blood sugar levels
- Applications of carbohydrate counting
- Dosing insulin therapy
- Diabetics use CC to determine the number of carbohydrates in a meal or individual food
- Carbohydrate amounts are then used to adjust premeal insulin doses based on a ratio of insulin units to carbs
- This may lead to tighter control of blood sugars and more freedom to vary food choices
- See insulin dosing for a review of insulin dosing and carbohydrate counting
- Following a diabetic diet
- CC can be used by diabetics to calculate the number of carbs they are consuming from foods
- This may help them achieve their caloric and carbohydrates goals
- CARBOHYDRATE INFORMATION
- Nutrition labels
- Labels on food packaging are required to list carbohydrate content (see food labels below)
- USDA website
- FoodData Central - contains nutrient information on thousands of foods including restaurant foods
- CARBOHYDRATES ON FOOD LABELS
- FDA requirements
- The FDA requires manufacturers to list certain nutrient values on food labels
- Some nutrients are required and some are voluntary. In regards to carbohydrates, the following is true:
- Required
- Total Carbohydrates
- Dietary Fiber
- Sugars
- Voluntary
- Soluble fiber
- Insoluble fiber
- Sugar alcohol
- Other carbohydrate
- Exceptions
- Certain foods that contain an insignificant amount of nutrients (ex. Diet Coke®) are exempt from the requirements
- Exempt foods are only required to list total calories, total fat, total carbs, protein and sodium
- Total carbohydrates (required)
- The sum total of all the different types of carbohydrates in a food
- It is important to note that when the grams of carbs from the subcategories of carbohydrates (ex. Fiber, Sugars) are added up, they may be less than the Total Carbohydrates
- This occurs because the category "Other Carbohydrate" is voluntary and not always listed (Example label #2 below illustrates this)
- Dietary fiber (required)
- Listed as "Dietary fiber" or "Fiber"
- Fiber is absorbed differently than other carbs, therefore it affects blood sugars differently
- Because of its unique properties, foods high in fiber are calculated differently than other carbs
- For CC, several approaches can be used to account for fiber
- A simple and common method is as follows:
- Locate the total grams of fiber under "Fiber" or "Dietary Fiber"
- If this number is ≥ 5 grams, then subtract the fiber grams from the Total Carbohydrates
- If this number is < 5 grams, then do not subtract fiber grams from Total Carbohydrates
- Sugars (required)
- Sugars are the sum of added sugars and sugars found naturally in the food
- For purposes of CC, they are included in the total carbohydrates and this category is not used
- Soluble fiber (voluntary)
- Soluble fiber is typically only listed on high fiber foods
- For CC, adjustments are only made based on the "Dietary Fiber", so this category is not used
- Insoluble fiber (voluntary)
- Insoluble fiber is typically only listed on high fiber foods
- For CC, adjustments are only made based on the "Dietary Fiber", so this category is not used
- Sugar alcohols (voluntary)
- Sugar alcohols consist of lower calorie sweeteners like sorbitol and mannitol
- Because sugar alcohols are not a required listing, they may be present in the food, but not listed separately on the label
- Sugar alcohols may also be counted under "Other Carbohydrate"
- Sugar alcohols only provide 2 calories/gram as opposed to 4 calories/gram for other carbs
- Because of this, sugar alcohols only count half as much as regular sugars
- For CC, the grams of sugar alcohols should be halved and then subtracted from the total carbohydrates
- If sugar alcohols are present, but not listed separately on the label, then it is not possible to make this correction
- Other carbohydrates (voluntary)
- Defined as the "difference between total carbohydrate and the sum of dietary fiber, sugars, and sugar alcohol"
- Other Carbohydrate = Total Carbohydrate - Dietary Fiber - Sugars - Sugar Alcohol
- If sugar alcohols are not listed separately, then they may be a part of other carbohydrate
- Other carbohydrate typically includes starches and oligosaccharides
- For CC, other carbohydrates are included in total carbohydrates, so this category is not used [1,2]
- GUIDE TO CARBOHYDRATE COUNTING
- Overview
- The serving size for the labeled food is located at the top of the label
- One serving will contain the amount of carbohydrates detailed in the label
- The amount of Total Carbohydrates is the starting value (25g from the example below)
- The amount of Total Carbohydrates will be adjusted in two scenarios:
- 1. The total amount of dietary fiber is ≥ 5g
- 2. Sugar Alcohols are listed
- Example label #1
|
Nutrition Facts Serving size 30g |
|
Total Carbohydrate 25g Dietary Fiber 8g Soluble Fiber 1g Sugars 6g Other Carbohydrate 5g Sugar Alcohol 6g |
| Carbohydrate counting steps | From label above |
|---|---|
| 1. Locate the serving size | A 30g serving will contain the amount of listed carbohydrates |
| 2. Start with grams of Total Carbohydrates | 25g |
| 3. Locate the amount of fiber under the title "Fiber" or "Dietary Fiber" | 8g |
| 4. If Dietary Fiber is ≥ 5g, then subtract it from Total Carbohydrates | Dietary Fiber is 8g therefore 25g - 8g = 17g |
| 5. Locate Sugar Alcohols if present | 6g |
| 6. Take half the Sugar Alcohols | 1/2 of 6g = 3g |
| 7. Subtract half the Sugar Alcohols from the remaining carbs in step 4 | 17g - 3g = 14g |
| A carbohydrate count of 14g would be used to calculate a premeal dose of insulin from the example above | |
- Example label #2
|
Nutrition Facts Serving size 30g |
|
Total Carbohydrate 16g Dietary Fiber 2g Sugars 6g Sugar Alcohol 2g |
| Carbohydrate counting step | From label above |
|---|---|
| 1. Locate the serving size | A 30g serving will contain the amount of listed carbohydrates |
| 2. Start with grams of Total Carbohydrates | 16g |
| 3. Locate the amount of fiber under the title "Fiber" or "Dietary Fiber" | 2g |
| 4. If Dietary Fiber is ≥ 5g, then subtract it from Total Carbohydrates | Dietary Fiber is 2g therefore do not subtract |
| 5. Locate Sugar Alcohols if present | 2g |
| 6. Take half the Sugar Alcohols | 1/2 of 2g = 1g |
| 7. Subtract half the Sugar Alcohols from the remaining carbs in step 4 | 16g - 1g = 15g |
| A carbohydrate count of 15g would be used to calculate a premeal dose of insulin from the example above | |
| NOTE: In
this example, Dietary Fiber (2g) + Sugars (6g) + Sugar Alcohols (2g) does not = Total Carbohydrates (16g) This is very common since Other Carbohydrates is a voluntary listing and often omitted |
|
- EXCHANGE SYSTEMS
- Exchange systems
- Exchange systems are another method of CC
- Food groups
- In exchange systems, foods are typically grouped into one of three categories:
- 1. Carbohydrates
- 2. Meats and substitutes
- 3. Fats and others
- Carbohydrates are further divided into three groups:
- 1. Fruits
- 2. Starches
- 3. Milks
- Servings
- Serving sizes for fruits, starches, and milks are then calculated so that they each contain approximately 15g of carbohydrate
- Patients are then able to "exchange" foods between groups [3]
- Example:
- If dinner is to consist of 3 carbohydrates, patient may select 2 fruits and 1 starch
- Or they may change their mind and eat 1 milk, 1 starch, and 1 fruit
- As long as they exchange 1 group for another, their carbohydrate count should stay close to their goal
- Resources
- Books are available that detail exchange systems
- The ADA has an online exchange system that can be used for free - ADA food advisor
- BIBLIOGRAPHY
- 1 - Code of Federal Regulations, Title 21, Sec 101.9
- 2 - Kulkarni K: Carbohydrate Counting: A practical Meal- Planning Option for People with Diabetes. Clinical Diabetes, Vol 23, Num 3,p120-123, 2005
- 3 - PMID: 16915796