Carb Ratio Testing on Pump

I’ve started another round of carb ratio testing to really nail down the settings on my pump. My basal rate looks great and I’m now testing the amount of insulin I give myself for specific grams of carbohydrate. Does anybody have thoughts as to how many grams of food you should eat when testing carb ratios? I normally eat about 45 grams at each meal but have upped my food to 90 grams to test my carb ratio. I figured the more I challenge my insulin with food using the current ratios I have, the more pronounced the potential mis-matches will become. Let me know if you have any great hints about basal testing, carb ratio testing, or correction ratio testing. Having a nicely tuned insulin pump makes diabetes less burdensome and much more predictable…it’s great!

I’ve always used the procedure and calculators at this site:

Scroll down to the “How To” section.

Interesting…in pumping insulin, this increase in carbs is suggested.

I think part of the challenge is that your response to insulin is not exactly linear. You actually become insulin resistant at higher blood sugar levels and higher insulin dosing levels. If you are trying to fine tune your I:C, it is probably best to match it to approximately the levels you expect to see in your meals and snacks. Just my thought.

I read your post about testing your Insulin/Carb ratio with interest. I’ll be very curious to see whether you get reproducible results from one day to the next. It looks like your control has been similar to mine, and that you are also pretty athletic. I recently started testing many times a day (more than 10) and weighing and recording my food intake to measure my Insulin/Carb ratio. I thought it would be straightforward, but unfortunately I found my ratio varies dramatically from one day to the next - I have measured it less than 2 and more than 20!! I’m still sorting out why but I believe its been a combination of counter-regulatory hormones causing insulin resistance from BG going too high, in addition to increased insulin sensitivity the day after exercising.

Anyway my advice is to start by focusing on one meal (since I/C ratio’s can vary from one meal to the next). It also helps if you have the same food or close to the same food every day (e.g. one sandwich and a piece of fruit) - that cuts down on the possible variability due to differences in glycemic index or variations in accompanying protein and fat. If you eat different meals then record that in your notes along with the insulin amount, carb amount and BG levels before and three to four hours after eating. You only want to do this on days where any previous bolus was more than three hours before this meal - otherwise its too hard to sort out overlap.

And make a note of days where you had a recent low BG, or high BG, or stress, or exercise or anything else out of the ordinary since these may be responsible for any differences in insulin carb ratios you see.

And please report back with your results!! I wonder whether the carb ratio variability I observed in myself is unusual or common.