Carbohydrate
Counting in Youth
with Type 1 Diabetes
Management of Diabetes in Youth, Biennial
Conference of the Barbara Davis Center for
Childhood Diabetes
July 12-16th, Keystone, Colorado
David Maahs, Darcy Owen, Franziska Bishop
Outline
Overview of data/literature on and
rationale for carbohydrate counting in
diabetes
Overview of practical aspects of
carbohydrate counting (i.e. what happens
when the MD asks the RD to “teach them
to carb count”)
Current research at the BDC including a
brief carb counting quiz
Youth with Diabetes Do
Not Meet Dietary Goals
(Mayer-Davis, JADA, ’06:689-97)
Figure. Percent of male and female youth with diabetes who meet dietary recommendations:
SEARCH for Diabetes in Youth participants in the dietary assessment protocol, prevalent 2001
and incident 2002. *P<0.01 for comparison of males vs females, adjusted for clinical site,
race/ethnicity, and parental education level. (Mayer-Davis, JADA, ’06:689-97)
Youth with Diabetes Do
Not Meet Glycemia Goals
Hvidore Data, Diabetes Care, 2001
Why Carb Count?
Need some methodology on which to base
rapid-acting insulin dosing with
meals/snacks
Can allow for more flexibility with eating for
people with type 1 diabetes
Theoretically, should better match insulin
bolus to carb intake and result in reduced
post-prandial hyper- and hypoglycemia
Why Carb Count?
Primary goal of diabetes management is
to normalize blood glucose concentrations
Both MDI and CSII require patient (or
parent) input of CHO to determine proper
insulin bolus doses
Other methods
Sliding scale?
Consistent CHO intake
Pattern management principles
Insulin:CHO ratios
Exchange or portion systems
GI (glycemic index) and GL (glycemic
load)
DATA
DAFNE study: course teaching flexible
intensive insulin treatment combining with
dietary freedom and insulin adjustment
– Improved A1c at 6 months (9.4% v. 8.4%,
p<0.0001)
– Improved ‘quality of life’ at one year
DCCT: using CHO/insulin ratios in
intensively treated group improved
glycemic control
Factors relating to post-prandial
glucose excursions
Mismatch of amount of insulin to ingested
CHO
– Poor CHO counting
Failure to account for macronutrient
content of ingested food
Mismatch of the timing of rapid acting
insulin bolus delivery and subsequent
insulin action to CHO absorption with
resultant post-prandial hyperglycemia
Other issues
Exercise, post-exercise
Rapid-acting insulin dynamics (onset of
action, peak action, etc)
Location of delivery (subcutaneous, not
portal)
Psychological factors?
Goals
Improve understanding of the role of
dietary factors and physical activity in
glucose excursions
Reduce glucose variability for
patients/improve quality of life
?Potential application for clinical care now,
for closing the loop for an artificial
pancreas later?
Tips for Carb Counting
Benefits of Adjusting Insulin for
Carbohydrates
Allows More Flexibility
– No need to stay within carb ranges for meals
– For patients on pump therapy or MDI eating
schedule can be much more flexible
More Advanced Form of Diabetes
Management
Potential for more accurate dosing
Pump therapy requires carb input
Other Considerations
Who will be responsible for carbohydrate
counting
– Parent, child or both
Math skills
Carbohydrate counting at school
– MDI
– CSII
Focus on Carbohydrate
Main nutrient that is converted to blood sugar
Emphasize total amount of carbohydrate not
the source
Carbohydrates are:
–
–
–
–
Starches- grains, beans, starchy vegetables
Fruits
Milk and Yogurt
Other Carbohydrates (i.e. sweets, desserts etc)
Diabetes Food Pyramid
Food Labels
Locate Serving Size
Locate total grams of
carbohydrate
Rules for fiber and
sugar alcohols
Starches
15 gm carb servings
1 slice bread
1/2 cup mashed potato
1 dinner roll
1/2 cup corn
1/3 cup cooked pasta, rice or beans
Fruits
15 gm carb servings
1 small piece of fruit
1/2 cup (4 oz) juice
1 cup cubed melon
1/2 cup canned fruit, light or juice packed
1/2 cup applesauce, unsweetened
Milk and Yogurt
1/2 pint or 1 cup (8 fl oz) milk = 12 gm carb
Go Gurt = 13 gm carb
Yogurt, light (6-8 oz)= 15 gm carb
½ pint or 1 cup chocolate milk = 25-30 gm
carb
Resources
The Calorie King Calorie, Fat and
Carbohydrate Counter- Allan Borushek
www.calorieking.com
www.diabetesnet.com- Salter 1400
Nutritional scale
www.nutritiondata.com- recipe evaluation
Text messaging service: Diet1 (34381)
Palm pilots
Calculating a Dose
3 Step Process
1st Step: Insulin to Carb Ratio
Determine how much insulin is needed for
carbs eaten at meal or snack:
 Count up total carb grams
 Divide total grams by ratio
Calculating a Dose
2nd Step: Blood Glucose Correction
Determine How Much Insulin is Needed to correct
blood sugar (bg) to target

Check bg

Calculate insulin amount needed to
bring bg into target range (i.e. … 1 unit per
50 over 150- Individualized)
3rd Step: Total Dose = Insulin needed for
carbs plus insulin needed for bg
Calculating a Dose
Insulin to carb ratio = 1 unit per 15 gm carb
BG correction = 1 unit per 50 over 150
Carb component: 60gm ÷15 = 4 units
Blood sugar correction: 250 -150 = 100
100÷50 = 2 units
Total Dose = 4 units + 2 units = 6 units
“Smart Pumps”- Do the math for you!
How do you determine a ratio
and blood sugar correction
factor?
Rules
– 1500 Rule
Blood Sugar Correction Factor
1500 divided by TDD = # of points (mg/dl) blood sugar will be
lowered by 1 unit of REGULAR insulin
– 1700, 1800, 2000 Rule
Correction Factor
Same principle as above – however for RAPID ACTING insulin
Depends on proportion of basal to bolus dose
– 500 Rule
Insulin to Carb Ratio
500 divided by the TDD
For RAPID ACTING insulin
How do you determine a ratio
and correction factor?
Food Records
– Time of day meal or snack is occurring
– Insulin – type and amount
– Blood sugar values
Pre-prandial
2 hour post prandial
– Food – type and amount
– Estimated grams of carbohydrates in individual food
items
– Activity
Poor Food Record
Excellent Food Record
Examples
Excellent Food
Record
– All food amounts listed
– Details about food
items
– Accurate carb
counting
– Adequate blood sugar
readings, including 2
hour post prandial
values
Poor Food Record
– Patient did not list food
amounts
– Not enough blood
sugar readings and/or
no 2 hour postprandial blood sugar
readings
– Inaccurate carb
counting
Food Records
From food records we can determine:
– If the patient is carb counting accurately
– An insulin to carb ratio
Amount of insulin the patient requires per grams of
carbs consumed
2 hour post prandial blood sugars
– Effects of exercise
– Other potential dose adjustments
Challenges to Establishing
Ratios
Patient is in their honeymoon and/or requires
very small amounts of insulin
Poor food records
Inaccuracy with carb counting
Erratic blood sugars
Inconsistent activity levels
Illness
Insulin resistance
Carbohydrate Counting in
Adolescents with Type 1
Diabetes (CCAT) Study
Franziska Bishop, David Maahs, Gail Spiegel,
Darcy Owen, Georgeanna Klingensmith, Andrey
Bortsov, Joan Thomas, Elizabeth Mayer-Davis
Management of Diabetes in Youth, Biennial Conference of the
Barbara Davis Center for Childhood Diabetes
July 12-16th, Keystone, Colorado
Introduction
CSII and MDI require patient input of
carbohydrate amount to determine proper
bolus insulin dosing.
Pilot study results evaluating the accuracy
of carbohydrate counting among
adolescents with T1DM are reported.
Subjects
Adolescents (ages 12-18) seen at the
BDC (using insulin-to-carbohydrate ratios
at least 1 meal/day)
Methods
Study Visit
Subjects recorded their estimate of portion size,
carbohydrate content, and frequency of
consumption.
Subjects assessed the carbohydrate content for
32 foods commonly consumed by youth.
Food presented as food models or actual food in
common serving sizes or self-served by subject.
Results
Study participants: n=48, age=15.2±1.8,
HbA1c=8.0±1.0%
For each meal, accuracy categorized as
“accurate (within 10 g)”, “overestimated (by>10
g)”, “or underestimated (>10 g).”
For dinner meals, subjects with “accurate”
estimate of carbohydrates had the lowest
HbA1c (7.7±1.0%) compared to HbA1c of
8.5±1.2% and 7.9±1.0% for “overestimated,”
and “underestimated,” respectively (p=0.04)
Results
Statistically significant overestimation
observed for 15 of 32 foods (including
syrup, hash browns, rice, spaghetti, and
chips)
Statistically significant underestimation
observed for 8 of 32 foods (including
cereal, French fries, and soda).
Results
Only 23% (11 of 48) of adolescents
estimated daily carbohydrates within 10 g
of true amount despite selection of
commonly consumed foods.
Only 31% (15 of 48) of adolescents
estimated daily carbohydrates within
20g/day.
What does this mean?
If an adolescent is overestimating how much
carbohydrates they eat by 17 g at dinner, and they are
using a 1:8 carbohydrate ratio, then 2 extra units of
insulin are being taken which could result in a low blood
sugar.
Or . . .
An adolescent underestimates the carbohydrates in a
given meal by 10 grams, and they are using a 1:5
carbohydrate ratio, then they would take 2 units less
than needed likely resulting in a high blood sugar
Conclusion
Adolescents with T1DM do not
accurately count carbohydrates
and commonly either over or
underestimate carbohydrates in a
given meal.
The Carbohydrate Counting Quiz . . .
Your Turn!
22?
34?
Instructions for Carbohydrate Quiz
The Answers
Label Reading Quiz
How well do
you do?
The Answers