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How To Calculate Insulin To Carb Ratio

Calculating A Bolus Dose For Carbohydrate

Inpatient – Insulin:Carb ratio and Insulin Prescribing
  • Use the Insulin to Carbohydrate Ratio to calculate your insulin dose.
  • ICR is the amount of rapid-acting insulin you need for a specific amount of carbohydrate in food. This is the number of grams of carbohydrates that 1 unit of rapid-acting insulin will cover.
  • Example: 1 unit of rapid-acting insulin will cover 10 grams carbohydrates. This may also be written 1:10.
  • The ratio may be different at different meals.
  • Using the ICR will control blood glucose best if insulin is given before meals. Calculate your ICR based on what you WILL be eating. We strongly suggest that rapid-acting insulin be given before meals.
  • NOTE: You may give insulin right after a meal if do not know the amount of carbohydrates that will be eaten, like with a very young child or sickness.

    • Do not give rapid-acting insulin when you eat carbohydrate to treat a low blood glucose or to prevent a low blood glucose.

    Insulin To Carb Ratio

    For patients with type 1 diabetes or insulin-dependent type 2 diabetes who take rapid-acting insulin when eating, it is important to understand the insulin to carb ratio, which can be used in planning the diabetics meals. It is relatively easy to do without having to worry about using math to calculate this ratio.

    When using the insulin to carb ratio, it is assumed that the carbohydrates we take in are responsible for increasing the blood glucose levels. Carbohydrates include simple sugars, fiber, complex carbohydrates, and starch. Fiber is not usually counted as part of the insulin to carb ratio because it doesnt break down well in the gastrointestinal tract and therefore does not increase the blood glucose levels as much as other types of carbohydrates. Fats and protein content are not counted in the insulin to carb ratio because they, too, do not increase the blood glucose level as much as carbohydrates.

    When diabetics eat a meal, they often use rapid-acting insulin, such as Novolog , Humalog , and Apidra . The diabetic may also use regular insulin, such as Humulin R and Novulin R, but these are slower in activity so they are less effective at decreasing the blood sugar accumulated during the meal.

    First Some Basic Things To Know About Insulin:

    • Approximately 40-50% of the total daily insulin dose is to replace insulin overnight, when you are fasting and between meals. This is called background or basal insulin replacement. The basal or background insulin dose usually is constant from day to day.
    • The other 50-60% of the total daily insulin dose is for carbohydrate coverage and high blood sugar correction. This is called the bolus insulin replacement.

    Bolus Carbohydrate coverage

    The bolus dose for food coverage is prescribed as an insulin to carbohydrate ratio.The insulin to carbohydrate ratio represents how many grams of carbohydrate are covered or disposed of by 1 unit of insulin.

    Generally, one unit of rapid-acting insulin will dispose of 12-15 grams of carbohydrate. This range can vary from 6-30 grams or more of carbohydrate depending on an individuals sensitivity to insulin. Insulin sensitivity can vary according to the time of day, from person to person, and is affected by physical activity and stress.

    Bolus High blood sugar correction

    The bolus dose for high blood sugar correction is defined as how much one unit of rapid-acting insulin will drop the blood sugar.

    Generally, to correct a high blood sugar, one unit of insulin is needed to drop the blood glucose by 50 mg/dl. This drop in blood sugar can range from 30-100 mg/dl or more, depending on individual insulin sensitivities, and other circumstances.

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    Example #: Carbohydrate Coverage At A Meal

    First, you have to calculate the carbohydrate coverage insulin dose using this formula:

    CHO insulin dose = Total grams of CHO in the meal ÷ grams of CHO disposed by 1 unit of insulin .

    For Example #1, assume:

    • You are going to eat 60 grams of carbohydrate for lunch
    • Your Insulin: CHO ratio is 1:10

    To get the CHO insulin dose, plug the numbers into the formula:

    CHO insulin dose =

    • The carbohydrate coverage dose is 6 units of rapid acting insulin.
    • The high blood sugar correction dose is 2 units of rapid acting insulin.

    Now, add the two doses together to calculate your total meal dose.

    Carbohydrate coverage dose + high sugar correction dose = 8 units total meal dose!

    The total lunch insulin dose is 8 units of rapid acting insulin.

    Total Daily Insulin Requirement:

    Raising a Child with Diabetes: Going to School

    = 500 ÷ TDI = 1unit insulin/ 12 g CHO

    This example above assumes that you have a constant response to insulin throughout the day. In reality, individual insulin sensitivity varies. Someone who is resistant in the morning, but sensitive at mid-day, will need to adjust the insulin-to-carbohydrate ratio at different meal times. In such a case, the background insulin dose would still be approximately 20 units however, the breakfast insulin-to-carbohydrate ratio might be breakfast 1:8 grams, lunch 1:15 grams and dinner 1:12 grams.

    The insulin to carbohydrate ratio may vary during the day.

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    Adjusting For Erratic Readings On Basal Bolus Insulin Therapy

    In erratic glucose patterns, most meals have a fairly even mix of high and in-target readings. e.g. Erratic most times of the day . The following are suggested steps to follow.

    1: Assess overnight basal3: Assess ISF

    ERRATIC STEP 1: Assess and adjust evening basal insulin to start the day in target.Glucose readings that are stable from evening to morning with no snack usually indicate appropriate overnight basal dosing. If not stable, adjust basal.

    ERRATIC STEP 2: Determine if meal boluses are adequate for each meal.

  • Find pre-meal readings that are in target for each meal. If the subsequent readings are mostly…
  • in target then the preceding meal bolus is reasonable. eg. Bfast 6.1 mmol Lunch 7.1 mmol
  • elevated , then increase the preceding meal bolus or subtract carb from breakfast Bfast 6.1 mmol Lunch 8.9 mmol. Increase bfast meal bolus or adjust ICR
  • low , then decrease the preceding meal bolus or add carb to breakfast ratio. e.g. Bfast 6.1 mmol Lunch 3.2 mmol. Decrease bfast meal bolus or adjust the ICR
  • elevated with a snack in-between, and the glucose reading before the snack is in target, then either the snack needs decreasing or the snack requires a bolus e.g. Breakfast 6.1 mmol before snack 7.8 mmol and ac lunch 13.3 mmol.
  • When To Adjust Your Childs Insulin Dose

    The role of insulin in your childs body is important: it allows their body to take the glucose from the food they eat and convert it to energy. Children with diabetes either no longer make insulin or cant use it effectively, which means they will need insulin injections to keep their body functioning as it should.

    Because insulin is so important to your childs health, its important to give them the right amount. If your child takes too much insulin, their blood sugar can become low, which can cause symptoms such as a rapid heartbeat, nausea, fatigue, and even loss of consciousness. If they dont take enough, you may notice symptoms of high blood sugars .

    Sometimes, your child may have high blood sugar, which can mean they ate more than theyplanned, got sick, or were stressed, among other things. In order to bring down their bloodsugar, theyll need an extra dose of insulin or a correction factor.


    Your child will also need insulin for the food they eat. Calculate this using your childs insulin-to-carbohydrate ratio the amount of insulin your child needs to cover a specific amount of carbohydrates from their food and drinks.

    Remember, there is no such thing as a perfect insulin dose. The insulin requirements are constantly changing so youll need to make adjustments on their doses or call the Diabetes Team if youre unsure what to do.

    Heres what you need to know about insulin-to-carbohydrate ratios, correction factors, and pattern ratios.

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    Advantages Of Intensive Insulin Regimens

    • While intensive regimens require more calculation at each meal, they allow for more flexibility in timing and in the amount of carbohydrate content in meals and snacks.
    • An accurate insulin dose will also result in better blood glucose control with fewer high and low blood sugars.
    • Changes in activity and stress can be accommodated without sacrificing glucose control.
    • Over time, high blood glucose correction can be separated from the food coverage. For example, if your blood sugar is very high , you can delay your meal and give yourself a correcting dose. Once your blood sugar falls below 200 mg/dl, you can inject your meal insulin and then eat.
    • Learning these important skills will make managing your diabetes easier.

    What Is An Intensive Insulin Regimen

    Figure Out Your Carb To Insulin Ratio! Prevent High/Low Blood Sugar

    Intensive insulin regimens attempt to mimic the bodys normal pattern of insulin secretion, and deliver replacement insulin using the concepts of basal and bolus insulin coverage.

    When you are intensively managed with insulin your medical provider will prescribe an insulin regimen for you, but these are the general principles:

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    How Protein And Fats Affect Carb Counting And Insulin Dosing

    It is also important to know that although proteins and fats do not have a direct effect on carbohydrates, they do affect the way carbohydrates are absorbed. A food that contains carbohydrates in addition to a high protein or fat content will be absorbed more slowly but the effect will be longer, that is, it will not generate such a high glucose peak but it will last longer. You may need to adjust your ratios as you learn how various meals impact you.

    How Do I Calculate My Insulin To Carb Ratio

    You take your total daily dose of insulin , this includes both long acting and mealtime insulin, and divide it by 450 if you are using short acting insulin . If you are using rapid acting insulin then you would divide it by 500. These are called the 450 and the 500 rule respectively.

    Example 1 : Levemir 23 units two times a day & Novolin R 6 units two times a day

    TDD = + = 58

    450/58 = 7.75g < This means that for every ~8g of carbohydrates eaten, you need to take 1 unit of Novolin

    Example 2: Basaglar 40 units a day & Novolog 4 units before each meal, three times a day

    TDD = 40 + = 52

    500/52 = 9.6g < This means that for every 9.6g of carbohydrates eaten, you need to take 1 unit of Novolog

    Remember to discuss your ICR with your provider or your certified diabetes educator before making any changes to your diabetes management. If you notice that your blood sugar does not return to normal levels after eating, check your carbohydrate counting and speak to your diabetes educator to make adjustments in your medications.

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    Growth Weight And Psychological Effects

    Intensive and appropriate insulin therapy and, consequently, better metabolic control have enabled an improvement in the growth prognosis of paediatric patients with T1D . Modern T1D care prevents abnormalities of the GH-IGF-I axis, which means that children with T1D can achieve a final height similar to their healthy peers .

    Females at a young age with T1D face a higher risk of eating behaviour disorders and, consequently, are more likely to have impaired metabolic control and diabetic complications . Furthermore, a cross-sectional case-controlled study has shown that there was an increased frequency of food disturbances in pre-teen and early-teenage girls with T1D . Rigid dietary patterns that do not conform to the habits and needs of patients might have an effect on the psychological development of children with T1D. An Australian 9-month before/after study that evaluated diabetes-related quality of life reported significant improvements in patient-rated life satisfaction after the introduction of CC. Often, the lack of flexibility in the management of meals and snacks is one of the worst aspects of living with diabetes, and adolescents especially ignore dietary advice. Thus, CC is an important tool allowing children and teenagers to manage their T1D more effectively within their own lifestyles . This psychological effect of CC could also be useful during the honeymoon period and the transition from adolescence to adulthood.

    You’ll Need To Calculate Some Of Your Insulin Doses

    How to calculate insulin dose

    You’ll also need to know some basic things about insulin. For example, 40-50% of the total daily insulin dose is to replace insulin overnight.

    Your provider will prescribe an insulin dose regimen for you however, you still need to calculate some of your insulin doses. Your insulin dose regimen provides formulas that allow you to calculate how much bolus insulin to take at meals and snacks, or to correct high blood sugars.

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    Carbohydrates: Total Or Net

    One of the most common questions people have is whether they should be dosing insulin for net carbohydrates or total carbohydrates .

    The answer is different for everyone. You can only learn whats right for you by testing your blood sugar repeatedly.

    Fiber is not metabolized by the body, and is therefore less likely to create a blood sugar rise than other carbohydrates. As a result, many people with diabetes find that their insulin doses are more accurate if they dose for net carbs.

    Others, however, find the opposite, and learn that they need to count total carbohydrates when it comes time to calculate insulin dosages.

    You might also find that different ingredients with identical carbohydrate and fiber counts affect your body very differently, or even that soluble and insoluble fiber have different effects.

    To find the net carbohydrates of a food item, simply subtract grams of fiber from the grams of total carbohydrates listen on the nutrition panel. .

    It Is Divided Into 3 Main Sections:

    The modules can be read in any order.

    However, if you are newly diagnosed, it is best to start at the beginning in Understanding Diabetes, and work your way through the material.

    Below you will find a guide to each module.

    As you will see, depending upon your individual therapy, you can choose exercise guidelines and self-management sections that are specific for your diabetes treatment. Additionally, throughout the program, Self-assessment quizzes are available to help you monitor your progress, and how much you are learning.

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    How It May Benefit People With Diabetes

    Diabetes is a chronic medical condition that causes persistent high blood sugar levels. In a person with type 1 diabetes, the pancreas does not produce a hormone called insulin, which helps reduce blood sugar. A person with type 2 diabetes produces insulin, but it does not work as well to lower blood sugar.For anyone with diabetes, counting carbohydrates is an important way of keeping blood sugar levels in a recommended range.

    Doctors typically recommend a diet low in refined carbohydrates and high fructose corn syrup, such as the CCHO diet, for people with diabetes.

    People without diabetes do not benefit from the CCHO diet because their bodys insulin responds appropriately to a rise in blood sugar after a meal.

    How To Calculate Insulin

    Using an insulin to carbohydrate ratio

    A fairly typical insulin-to-carbohydrate ratio is 1 unit of insulin for every 15 grams of carbohydrate. However, the ratio varies considerably from one person to another, and a persons own ratio may change over time or even from meal to meal. For instance, a person may need 1 unit of insulin for every 10 grams of carbohydrate at breakfast but 1 unit for every 15 grams of carbohydrate in the evening. This can be due to factors such as how much insulin is already in a persons system, how much physical activity he has done, and fluctuations in his hormone levels throughout the course of the day.

    Your health-care team can help you determine your own insulin-to-carbohydrate ratios based on your blood glucose and meal records. Be sure to note the number of grams of carbohydrate in the meal, your blood glucose level before the meal, the number of units of insulin in the premeal bolus, and your blood glucose level 34 hours after the meal. Its a good idea to gather 1014 days of data before settling on a ratio.

    Disclaimer Statements: Statements and opinions expressed on this Web site are those of the authors and not necessarily those of the publishers or advertisers. The information provided on this Web site should not be construed as medical instruction. Consult appropriate health-care professionals before taking action based on this information.

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    Carbohydrate Counting With 300 Rule

    In the morning, the body is less sensitive to insulin, which is due to the fact that hormones released during the night make the body less susceptible to insulin. Therefore, as a rule, a larger dose of insulin is needed for breakfast, compared to other meals during the day.

    Heres how to do it:

    Divide the figure 300 by the total amount of insulin you use in 24 hours. The total amount of insulin should include both long-acting and fast-acting insulin. When you divide 300 by the number of units of insulin, you will get a figure showing how many grams of carbohydrates 1 unit of insulin will suffice.


    Johan uses 25E Lantus and 25E Humalog daily. In total, Johan uses 50E insulin.300/50 = 6This means that 1E insulin is enough for 6 grams of carbohydrates.For breakfast, Johan intends to drink milk and eat sandwiches, which in total contains 60 grams of carbohydrates. Then Johan needs the following insulin dose: 60 grams/6 = 10E insulin.

    Is There A Guideline Or Formula For Calculating The Number

    A: There are several ways to determine how much mealtime insulin to take to cover carbs. One method is to use what is known as the 1500 or 1800 Rule. One needs to calculate the entire daily dose of insulin and divide that amount into 1500 or 1800. The resulting number is a starting point for determining and fine-tuning the insulin-to-carb ratio. Another way to figure out insulin coverage for carbohydrate is to keep food records for several days, add up the carbohydrate at a particular meal, say, breakfast, and note how much mealtime insulin you took to cover those carbs . Sometimes healthcare providers will start a person off with a 1:15 ratio, which assumes 1 unit of insulin covers 15 grams of carb. Of course, this approach can be way off for people who usually require much more or less insulin. Its important to keep in mind that one may have a different ratio for each meal. If youre interested in trying what is often called advanced carb counting, Id strongly encourage you to meet with a dietitian who is well-versed in diabetes, because this level of carb counting is more of an art than a science. It requires careful and accurate carb counting , logging of both food and blood glucose, and frequent blood glucose monitoring to evaluate the ratio and then fine-tune it if its not correct. Also, in addiContinue reading > >

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