Basal rates related to food consumption

I know that there is a general rule-of-thumb which says that basal insulin has nothing to do with food. You bolus for food and you take basal for when you are not eating. And people are told that you do basal testing by not eating during those hours for which you are trying to setup your basal rates.

This information can be useful for people who are just starting out and who are trying to get their basal rates setup. It is just a basic description which does help people distinguish between mealtime insulin and non-mealtime insulin. It is a great starting point for getting an understanding of how it works.

But for those who have spent enough time with the disease, let me say something that is heresy:

Your basal rates have very much to do with how much you are eating. You can not completely distinguish basal insulin from your food consumption.

There, I said it! :open_mouth:

There is a reason for this. Despite what we may think of ourselves, we are still very primitive animals. For most of us, food is generally always available. We don’t have to go out and catch our meals, or grow them. Our meals do not depend on seasonal changes or migratory patterns.

But go way back. Imagine a time when food was not readily available. How would the body adapt to this?

During times of starvation or scarcity, the body wants to conserve its energy. Not having a constant supply of fuel (food) means that the body wants to spend as little of it as possible. So the body slows down its metabolism. Spending less of its resources means less stored energy is used for basic functions. And that simply equates to less insulin being needed during this time.

And the opposite is true during times of feasting. The body interprets that larger quantities of food means there is plenty, so it will use more energy. It will burn more fuel because it believes more is available. Burning more fuel means that the basal metabolic rate is higher. And that equates to needing more insulin in your basal rate.

I wanted to post this today, because perhaps some of you noticed a bit of a change if you spent 4 days gorging on Thanksgiving food.

Do basal rates have anything to do with how much we eat? Absolutely!


I always knew that I liked you, @Eric.

Thank you for helping me visualize the “why” and the “how” behind this. I see the most pronounced increase in my basal needs due to eating on my sedentary work days. Although being at a desk most of the week is a pain in the neck from a health and blood sugar perspective, it does provide me with the opportunity to see this eating effect on basal needs (as well as hormone effects) in an exaggerated, controlled, repetitive environment. I hope that these observations not only help me with my understanding of best treatment strategies, but that they might help other FUDders, too.


Eric, what will be a good guideline to adjusting basal rate during these feasting days? 10% more? perhaps more?


It can be different for everyone. Try 10%, try 15%, try 20%, or whatever you need.

I have bumped up a lot after crazy eating days. But the best thing is to just try different amounts and see what works best for you. And you will always have another chance to try again!


@ardipa, for us, Thanksgiving weekend meant +5% basal for 4 days, and +10% basal for some parts of the day (a couple of nights). But we may not have splurged as much as some? We took @TravelingOn’s recommendations, and did deserts for 2 days, then big lunches/ dinners for two days but with less sweet deserts.

But, on these kinds of changes, I think the adjustments are very individual.


And as a case in point, even though I managed to stay within my target range during the aforementioned Thanksgiving Feast, due to extra large dosing and extended bolusing, my subsequent glucose levels peaked for days afterwards, and just this morning started to settle back into their pre-Thanksgiving levels.

Hmmm… maybe if medical science could figure out a non-detrimental way to interrupt that “feast/famine” signalling process?

Which, in a way, is kind of what those who subscribe to alternate fasting techniques attribute their successes to…

OK far enough out on a tangent at this point to just wander off, mumbling to my self!



Thanks for doing this, Eric. I’ve said it here before, but I’ve definitely found fasting (all day, less than half of normal calories) results in need to cut basal by 50% for me.