Confused about Insulin Carb ratios

CathyFP

CathyFP

Well-Known Member
Relationship to Diabetes
Type 1.5 LADA
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She/Her
Is there any very simple information about how to work out your correct Insulin unit to Carb grams ratio. Everything I read is SO complicated. I have data on meals I have eaten where I have managed to get the dose right(ie I have stayed in the green after a couple of hours and not gone high or low) but I’m still not really sure how to calculate a ratio from this data to apply to other meals. Can anyone help? Thanks
 
I am not sure what formula you are using but ...
- before sorting out insulin to carn ratios, you need to be confident your basal is correct. Otherwise, your bolus will be correcting basal issues.
- our insulin sensitivity can vary at different times of the day. For example, it is common to be more insulin resistant in the morning. And when you are unwell, it may increase. Your other posts suggest you have been poorly. If you are still recovering, it is not a good time to calculate your normal ratios.
- fast acting insulin lasts about 4 hours so you need to be back to "target levels" after 4 hours. If you are at these levels after 2 hours, you may go too low. I recommend ignoring the 2 hour advice - it is for people with type 2, not Type 1.
- the ratio is a guidance. It may change and it requires rounding. As there are many things that affect BG and the carb contents of a meal are an approximation, do not expect perfection every time. Unless you eat the same food every day, do the same exercise, never get ill or stressed or too hot or too cold or...
- I think most people calculate insulin to carb ratios through trial and error rather than a formula. It is common to start with 1:10 and then adjust accordingly.
Sorry if this confuses things further.
 
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CathyFP said:
Is there any very simple information about how to work out your correct Insulin unit to Carb grams ratio.
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It's not something that's calculated. These ratios (because they'll almost certainly be different at different mealtimes) are estimated to begin with and then adjusted as you find out how well they work, probably over a few days with the help of your healthcare team.
 
Unfortunately it is a bit hit an miss in my opinion - my ratios depend a lot on time of day, plus the type of food you are eating and physical activity - and you will never get it perfect so don't despair! I range from 0.5 Units per 10g Carbs to 1.5 Units per 10g of Carbs depending on what I am are doing/eating - some people will be more or less than this - It is a nighmare to start with but I promise it gets easier (I'm only 2yrs into diagnosis myself)
 
mashedupmatt said:
Unfortunately it is a bit hit an miss in my opinion - my ratios depend a lot on time of day, plus the type of food you are eating and physical activity - and you will never get it perfect so don't despair! I range from 0.5 Units per 10g Carbs to 1.5 Units per 10g of Carbs depending on what I am are doing/eating - some people will be more or less than this - It is a nighmare to start with but I promise it gets easier (I'm only 2yrs into diagnosis myself)
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Thanks @mashedupmatt and others. Does sound so complicated, I will just keep experimenting. My Diabetes nurse just told me I was doing really well as I am 80% in range but I’m having lots of highs and lows which worries me.
 
CathyFP said:
Thanks @mashedupmatt and others. Does sound so complicated, I will just keep experimenting. My Diabetes nurse just told me I was doing really well as I am 80% in range but I’m having lots of highs and lows which worries me.
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Sounds like you are doing really well @CathyFP

The closest I’ve seen is this conference slide, for estimating TDD (total daily dose) and then likely basal (40-60% TDD) and ratios/factors - but this is only the starting point.

1721637090597.jpeg

Then comes the fine-tuning that you are currently doing. Which involves:

Basal testing: To get it as ‘right’ as possible
https://www.mysugr.com/en/blog/basal-rate-testing/

Observation around pre-meal and post-meal BGs:
Are you back to premeal level after 4-5 hours?
Did any correction you added work effectively?
Was any high level at 1-2hours the result of insulin acting too late (do you need to pre-bolus)?
Did your levels drop quickly, but then rise for several hours later (do you need to split your bolus before and after the meal to spread the action for slow-absorbing meals)

And also:
Is it diabetes randomness? Is this a pattern that repeats, or just a one-off on the day
What level of exercise/activity have you done in the last 24-48 hours? Next 4-8 hours?
Any alcohol?
Are you possibly ill?
Are you stressed?
Or excited?
Is it warm? Or cold?
Are the seasons changing?

And…
Are you wearing the correct colour of socks?
What is the current phase of the moon?
 
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victorhamesse said:
I always wear odd coloured socks.
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Ah… but are they the correct colour combination(s), in relation to the current phase of the moon (+/- wind direction, obviously)…

Only your diabetes will know for sure! :D
 
I tend not to worry too much about insulin/carb ratios. I still use the 1:10 guidance I was started on because it is close enough and easy to calculate and with mostly eating low carb, it means that it is usually only multiplied by 2 or 3, so never going to be too far out. On the odd occasions I have more carbs like yesterday lunchtime when I had a sandwich and salad and some crisps, 6 units worked out pretty well. If I need more later, then I just jab a correction or if it was a bit too much a single dried apricot of prune or fig or jelly baby levels me out. I think now that we have CGM carb ratios are much less important than they were when we we reliant just on finger pricks, because we can now see when levels are rising or falling and take action if necessary.
I use my Libre to tell me when I need a correction and my high alarm is set at 9.2 and usually if I hit that level and my alarm goes off, I know from experience that I need 2 more units, unless it is not long after I bolused and ate.
The really important thing for me is getting my basal doses right and that is why I love Levemir so much, because it allows that flexibility to adjust for exercise or being more sedentary or hotter or colder days or illness or alcohol, although I no longer drink, so that doesn't come into my considerations anymore. I average low-mid 90s% TIR following this approach and it makes my diabetes much less taxing than weighing and measuring food and calculating difficult ratios. Of course it took me time and experimentation to work out this system which works for me with my diet and lifestyle using Fiasp and Levemir.

All I am saying is that I have never stressed about insulin/carb ratios and unless you eat quite a lot of carbs, I am not sure you need to know if you need 1:8 at breakfast or 1:13 at lunch. I am not saying 1:10 will work for everyone and you might need be nearer 1:5 if you are a bit insulin resistant or 1:15 or even 1:20 if you are very sensitive to insulin, but I think perhaps people try to be too precise with it when there are so many other variables which can impact it on a day to day basis and I think that now we have Libre and other CGM we can be more relaxed about this aspect of our diabetes management.

Those are just my thoughts from my own experience. For me the key thing for good diabetes management is to get as close as possible to the "best fit" with your basal insulin both in terms of an insulin which suits your body and lifestyle, be that shorter ones like Levemir or Humulin I or longer acting ones like Tresiba or something with a peak of activity like Glargine/Lantus and then getting the right dose(s) of that basal insulin and the timing of them (timing of basal can be more important than you expect with some basals), to keep you as steady as possible.
 
CathyFP said:
Thanks @mashedupmatt and others. Does sound so complicated, I will just keep experimenting. My Diabetes nurse just told me I was doing really well as I am 80% in range but I’m having lots of highs and lows which worries me.
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It’s normal to have highs and lows. Whats the % low from your time in range? The target is 4% or less.

The highs are fine if you’re 80% in range as the target is 70% in range or more.
 
Hi @CathyFP

For me, I use only 3 regular ratios all based on background glucose (with basal dose being 19u tresiba) being pretty level over the entire 24hr day.

1. Upon waking. 3 units humalog for every 10g of carbs.

2. 12pm onwards. 2 units humalog for every 10g of carbs.

3. 3pm onwards. 1 unit of humalog for every 10g of carbs.

Clearly more resistant upon waking. Morning humalog always taken well before eating, typically 20 mins.

To find your typical ratios, it's easier to initially stick to same meals/carbs, same times of day and make a note and adjust accordingly.

This is the basics. Too many other factors to mention. Exercise being the most relevant on a typical day.
 
Hi @CathyFP
I am another one with ratios that change through the day. I started with 1:10 and then over time and with improved tech I have fine tuned my ratios, and also the timing of my bolus. My pre-bolus timing is more in the morning than in the evening (and even then they are my intention but it is not always possible to do this: eating out, forget as I am in the middle of cooking, …
 
Thanks everyone for all the responses and information. It will probably take me awhile to digest and do some experimenting.
 
I've always found this very confusing and it's now 6 years in and it's still chaotic and confusing. Nothing has improved or gotten better. I took 30 units of the slow nearly 2 weeks back in the morning to see if my levels would go down as they kept going up randomly. Now i feel like it might have had a side effect to which i can barely explain. I'm not sure if the sensor is wrong or broken. I tend to notice that it goes down fast when i lay down as well. It's made me more paranoid tbh and it got so bad, i didn't even take any quick units before or after food.

I've kinda just given up now.
 
Don’t give up @Mickeyminime It sounds like you just need a bit of support with your blood sugars and corrections. If you’d like to start a thread detailing recent problems you’ve had, you’ll get suggestions about what angle to approach them from.
 
Mickeyminime said:
I've always found this very confusing and it's now 6 years in and it's still chaotic and confusing. Nothing has improved or gotten better. I took 30 units of the slow nearly 2 weeks back in the morning to see if my levels would go down as they kept going up randomly. Now i feel like it might have had a side effect to which i can barely explain. I'm not sure if the sensor is wrong or broken. I tend to notice that it goes down fast when i lay down as well. It's made me more paranoid tbh and it got so bad, i didn't even take any quick units before or after food.

I've kinda just given up now.
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@Mickeyminime Dont give up let’s get help on here and try to crack this together. It’s important.

What sensor are you using? I’m using Libre2. If you get lows on your sensor when you lay down it could be that you are lying on the sensor and compressing it which can give an incorrect compression low.

I’m focusing on trying to get my insulin right for one meal a day at the moment (breakfast) by eating pretty much the same thing and gradually increasing my insulin dose to try to reduce the post meal high. Maybe you could try something like that? Good luck and let me know how you get on
 
I have only been on insulin since the beginning of the year when they started me on the 1:10 ratio. Since getting my CGM and getting used to things I think I'm mostly "sorted"... But ...
There are days when my pancreas decides to do some work and others when it falls flat in its proverbial face! Being type 3c with an undecided pancreas isn't what I call fun.
My basal is anything between 5 and 15 depending on whether it's on strike, though mostly around 7 when is behaving.
My bolus ratio is higher in the morning, between 1:3 to 1:8 and changes during the day ending at between 1:8 to 1:12.
The DSN talked about finding a balance, honeymoon period etc. but it really is down to your body and how you work. A few people warned me about this when I joined the forum and I always think of @everydayupsanddowns when people ask about insulin levels... because that's what it is... Every day may well be different!
I use an app the make my carb counting easier and then something like gluroo which has an aid in the form of a table to give an estimate to how many units I should take depending on time of day, but you have to get to know your own body and which foods do what to your BG levels too...
 
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