Do you live with insulin-dependent diabetes mellitus or count your carbohydrates accurately, but still struggling with high or hypoglycemia after meals (after meals)?
In that case, the “insulin to carbohydrate ratio” may need to be adjusted.
The insulin to carbohydrate ratio is a number that indicates the rapid insulin needed to cover a certain amount of carbohydrates. It is what allows you to accurately administer insulin for your diet and correct hyperglycemia.
In this post we will cover your insulin to carbohydrate ratio, how to find yours, the factors that may affect it, and the tools and mobile apps available to help you find and track your ratio.
If a doctor is changing the insulin to carbohydrate ratio, much of the information discussed in this post is relevant to bringing to the doctor so that informed changes can be made to diabetes management.
What is the insulin to carbohydrate ratio? Why is it important?
The insulin-to-carbohydrate ratio (also known as “carbohydrate ratio” or “carbohydrate factors”) indicates the number of grams of carbohydrate in one unit of insulin cover that acts rapidly to ensure that blood sugar levels remain within the desired range.
Carbohydrate ratios are often set by your doctor first when diagnosed, but should be updated regularly (if necessary). A 1:10 carbohydrate ratio means that one unit of rapidly acting insulin covers 10 grams of carbohydrates. A higher ratio indicates that there is less insulin needed to cover carbohydrates.
Let me give you an example:
If my carb ratio is 1:10 and I’m eating 30 grams of carbs, I need 3 units of rapid insulin to cover my diet (dividing 30 pieces by 10). However, if my carb ratio is 1:15, I only need 2 units of quick-acting insulin (divided by 30 by 15)
High carbohydrate ratios mean low insulin is a key fact that while it can take a little time to wrap around your head, it’s a key fact when you start adjusting your carbohydrate ratios.
Calculating insulin peaks in diet means that the exact carbohydrate count and exact carbohydrate ratios will remain within the desired range and below 180 mg/dL (10 mmol/L).
If your diet’s insulin timing is off, but the carbohydrate count to carbohydrate ratio is correct, you may notice that your blood sugar levels are slightly out of range, but should return to range within 90 minutes (this is the average insulin peak).
It is also important to note that before calculating your insulin dose, you need to subtract the dietary fiber content from the total carbohydrate amount, as fiber does not completely break down in the digestive system and thus prevents blood sugar levels from rising. Administration of fiber can lead to hypoglycemia.
How to calculate carbohydrate ratios
If you suspect that your carbohydrate ratio is off (often running high or low after a meal can be a good indicator), it’s time to collect data in the form of blood sugar levels and do some analysis.
If you want good results, you need good data and you are the only one who can collect it. Like most other things related to diabetes, it requires work, but it’s worth it.
It is recommended to collect data to assess whether the carbohydrate ratio is correct, lasting at least 3 days following the four steps below. If you and/or your doctor do not see the trend after 3-5 days, you should collect more blood glucose data.
- Focus on one meal at a time (for example, breakfast). Enjoy your meals at about the same time every day, and try eating the same food and quantity during the data collection period (this is a good place to start breakfast as it is easier to eat the same food for breakfast every day).
- Make sure your carb count is correct and stick to the same carb ratio for data collection period
- Do not do anything that has a major effect on your blood sugar before and after meals (such as going for a run).
- It is located on a blood glucose measurement or on a continuous glucose monitor (CGM).
- Measure your blood sugar level before meals
- Measure your blood sugar level after meals (90-120 minutes after injection)
After 3-5 days, sufficient data is required to assess whether the carbohydrate ratio at this time is accurate.
When you or your doctor perform the analysis, you will focus on whether your blood sugar was within your desired range before meals and whether your blood sugar returned to your desired range within 90-120 minutes of your insulin injection.
Note: It’s difficult to assess whether the carbohydrate ratio is accurate, so try not to take corrected insulin doses when testing carbohydrate ratios, but if your blood sugar levels are dangerously high or higher than you would like, go ahead and correct them. You can continue your carbohydrate ratio experiment any time on another day. Always safe and secure!!
Let’s look at two different scenarios, assuming a 30 carbohydrate diet (counted as accurately as possible) and a starting carbohydrate ratio of 1:10.
Blood sugar levels range before meals, but high after 90-120 minutes
If your blood sugar levels aren’t back to range or come down immediately after 90-120 minutes of meal, your carbohydrate ratio is too high. You can consider trying to experiment with a ratio below 1:10. Probably 1:9 or 1:8 is the right ratio.
I don’t want to change my ratio too dramatically. Because I want to run a little higher for a few days than ending with a nasty hypoglycemia. The lower the carbohydrate ratio, the more you need insulin per gram of carbohydrate.
Blood sugar levels are in the condition before meals, but low after 90-120 minutes
If your blood sugar levels are lower than your target range 90-120 minutes after eating, the carbohydrate ratio is too low. You can consider trying to experiment with ratios above 1:10. You may need to go 1:11 or 1:12. As mentioned before, I usually do small incremental changes.
You should also consider whether the timing is off when taking insulin. If you have hypoglycemia within 30-60 minutes of the injection, the food may have not yet been fully digested and will later bump into the bloodstream. This can be assessed by measuring it frequently and experimenting with taking insulin a little later.
Note: The carbohydrate ratios listed here are just examples. It can have a much higher or lower ratio than 1:10.
What affects carbohydrate ratios
Our bodies change over time, and our diet and exercise patterns change. With your body and your daily changes, you will find that you need to adjust your carbohydrate ratio.
Here are five things that affect your carbohydrate ratio:
time
You may have noticed that most people have multiple carbohydrate ratios, so they write “carbohydrate ratios.” For example, many have high insulin resistance in the morning, which can lead to lower carbohydrates for breakfast than for lunch or dinner.
In theory, you can have as many carbohydrate ratios as you like, but most diabetic devices (pumps, apps, SmartPens) are limited. Mine has four and I use 3. I have the lowest ratio for breakfast and the best ratio for dinner and overnight.
Month Time (for women)
Variable hormone levels in the menstrual cycle can have a major impact on blood sugar levels and insulin needs. This means that different carbohydrate ratios (and possibly basal insulin) are required for periods of time when there is extra insulin resistance due to hormonal changes.
I am one of the women who see a huge difference in my insulin needs throughout my cycle. You need to have a significantly lower insulin just before the day and always increase the carbohydrate ratio.
Diet Type: Effects of Protein and Fat
Carbohydrates may be the ones that are converted to glucose, the fastest bloodstream in the bloodstream, but they are not the only macronutrients that can affect blood sugar.
Eating large amounts of protein requires insulin to inject it to prevent blood sugar levels from increasing.
Adding large amounts of fat to your diet is likely to cause delayed release of glucose into the bloodstream. This means that for many people, you need to take not just one, but two insulin doses.
Movement/Motion
If you are more or less active than usual, you should consider it when calculating your insulin dose. If you take bolus insulin 30-60 minutes before training, you will often need to reduce the dose by 25-75%. It’s a big range and you need to find the right reduction for you.
If resistance or interval training is sometimes not necessary to reduce, these types of training may need to increase blood sugar levels, as they can increase blood sugar levels.
body weight
If your weight changes significantly, you will see that insulin needs to change too.
If your body fat percentage increases significantly, you may experience the need for more insulin to cover your diet. On the other hand, if you gain a significant amount of muscle mass, you will see that you need less insulin to cover your diet.
When managing diabetes using an insulin pump, it is very easy to use carbohydrate ratios. Most pumps have a bolus calculator built in (calculate the proposed dose) and the medical team needs to set it up for you and train you on how to use it. In that case, you simply focus on whether the ratio is accurate or not.
If you want to manage diabetes with manual injections, you will need to look elsewhere for a “carbohydrate calculator” and remember or write down the ratio. The advantage of a great calculator is that it can track active insulin (insulin lasts for 3-5 hours in the body) and helps track injections and ratios.
Mobile App: There is no FDA approved standalone app approved for administering recommendations in the US, but using RapidCalc (not FDA approved) I found it to be accurate and easy to use.
Outside of the US, the best options are the Hedia and MySugr apps.
Smart Insulin Pen: Companion Medical’s Inpen is a SmartPen only available in the US. With the exception of actually pumping, it has all the functions of the pump, so it automatically tracks active insulin and has a bolus calculator. Send data directly to your mobile phone via Bluetooth.
Smart Meter: Some blood glucose meters have the bolus calculator feature or an app that links it to the meter.
Don’t expect perfection!
This post may have thought a lot for you – and I know that I’m probably working on it. I recommend including your medical team as long as you need it.
A good place to start is the carb ratio for breakfast. When you think you’ll beat it, you can move to lunch, then dinner, then snacks.
And you don’t always do that right. We don’t have complete information about what’s going on in our bodies, and one day, your normal ratios don’t work. That doesn’t mean they aren’t suited to you. Give me a few days to see if things get back to normal.
However, if you continue to experience high or hypoglycemia after meals, it may be time to fine-tune your insulin-carbohydrate ratio.
