IC ratio or insulin sensitivity....what’s the real issue


So, I use the 670G and started a strict ketogenic
diet a week ago. I am finding that my mealtime boluses are not covering the tiny amount of carbs I’m eating, so I end up hovering around 150. Then, when I correct my BG (my target is 85-100), I still seem to hang out between 130-150. My IC ratio is 1:10 and my insulin sensitivity is about 60 (which is accuarate for the roughly 17 units I take daily)…any ideas why I’m having trouble with mealtime and correction boluses? Thoughts of if the keto diet could be affecting things?

Hi Alice @AliceD, first a Warm Welcome to the TypeOneNation Forum!

Starting anything new, like your strict keto diet will almost always pop in a few of the unexpected. You didn’t mention what your prior diet was like or how long you have been living with diabetes so my response has to be very general. My initial observations - and I’m not a Medical Doctor but my life has existed for the last 62 years with injected/infused insulin - are:

  • How recently have you validated your insulin sensitivity for the time of day in question? My sensitivity varies depending on time of day and has chanced over time - my lunch-time is the same as your 60.
  • Carbohydrate ratios too can change with time of day and should be evaluated occasion.
  • I have only a general knowledge of the keto diet [I eat a relatively high carb diet] so I’ll only suggest that you look for hidden carbohydrates.

Best wishes for your exploration.

@AliceD hi Alicce, agree with @Dennis. Eating low carb, super low carb, or no carb will affect your basal rate your sensitivity and your IC.

you are forcing your body to convert fats to energy, but you can switch back and some argue you switch back faster (as in a change in overall metabolism) if there are carbs present.

are you in auto mode? the hanging out at 150 would be a basal issue if you were in manual. You can’t fix that with additional meal time insulin.

as you become accustom to this new diet, your basal requirements, sensitivity (which can be more body mass based) and your IC will eventually settle down. re-test them when it’s convenient. good luck.

Hey Denis,

Thank you for your feedback…I have had type 1 diabetes for 22 years, since 1997, and I was 17 at the time of diagnosis. Prior to this diet, I ate a whole30 diet…so no grains (except for fiber one cereal), lots of fruits and veggies.

How do you Decide where your ic ratio or insulin sensitivity should be according to the time of day?

Alice, I just posted about this in another post.
When you eat low carb, you also need to take into consideration that Protein also needs insulin. Almost up to 50% of the protein is slowly converted to sugar.

If you use a CGM, you will notice that another or two after eating, your sugar will slowly rise, that is from the slow conversion of Protein into glucose for your metabolism to use.
For some people, they need to bolus for up to half of that protein as well to cover that process.

Dr Bernstein has a lot of info in his books about it as his diet is also a low carb diet (but very regimented)

Hope it helps!

You are welcome Alice @AliceD. I’m not a medical doctor and the suggestions I offer come from my more than 60 years living with diabetes; I received my “diabetes” diagnosis on my 16th birthday - at about the same age you received yours.

I figure my I:C ratios by trial and error mostly by taking insulin for a “perfectly” calculated carb meal; get a BG reading before the meal and do checks after eating at 1, 2, 3 hours after. Depending on those results make adjustments on following days; of course do this on days without extraordinary activities.

For “insulin sensitivity”, on a day without anything out of the ordinary, and if my BG is at least 150 mg/dl I will take one unit of insulin and recheck again at 2, 3 & 4 hours.

I began MDI with “guessed at” I:C ratios in the 1970’s before the advent of BG Meters - then it depended on how I felt and on urine testing. Wild, but it worked for me.