Do basal needs depend upon how much food you eat?

Branching out in another direction on this topic, is it possible that our necessary basal rate in the absence of food (basal testing) is lower than our necessary basal rate in the presence of food?

My experience is that boluses just can’t do enough to cover my meals, and I run higher all the way around during the day when I’m eating despite aggressive bolusing, extended bolusing and correction doses. Extra basal seems necessary when I’m not in a fasting state…which makes basal testing confounding when it comes back perfect in a fasting state. I’m already at a 70/30 split nearly everyday and I still haven’t gained any weight in four months of trying…which is to say that I can’t imagine I’m under bolusing for food and I’m certainly not over-eating.

Absolutely. During times of minimal or no eating, my basal drops way down. Food intake affects basal. Yes, 100% true.

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I concur with @Eric, the days I fast for Ash Wednesday for instance, I cut my basal way down, or else I’m going hypo all day.

The funny thing is, I’ve read of basal testing procedures(on other d forum sites) which involve fasting for testing the basal rate. I now wonder how representative this would be.


What methods would work better for determining basal rates when eating? I’m doing a whole lotta trial and error with my 5 million variables and am getting closer to a successful basal/bolus split…but do you (or anyone) have any tips I could use?

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The only tip I have for this is delay (or skip) the meal, so you can see what the BG would have done based only on the basal, in the absence of carbs and meal bolus.

For me, the “lower basal requirement when fasting” occurs when fasting for a long time. A 6-hour fast doesn’t matter. It starts to matter at 12 hours, and definitely at 24 hours.


for Samson we see an effect after about 8 or 9 hours. But he’s little.


I am really intrigued by this. We have not seen a difference in basal needs when we change the number of calories in a day by a significant amount. But it is possible that we have not been observant enough.

What puzzles me, though, about fasting, is that if we don’t take food for long enough that we miss a meal and keep on going, we typically see a rise in BG, not a drop.

[Gave the topic its own thread btw]

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I have only observed this reliably on my work days. I’ve eaten the same breakfast and same lunch on work days for four years. I think I don’t observe this same effect on the weekends bc either (a) my activity levels make up for it or (b) I have such inconsistent activity levels/meal composition that I’d never be able to suss it out.

But on work days when I’m at my desk all day…even if I go out and walk four times a day…it is SO noticeable. It seems to me that if I don’t add 10% basal while in my sedentary time at work to help with eating, I have to increase my boluses by 30-40% to accomplish the same thing…and even that isn’t pretty and leads to a whole other set of collateral damage. But if I’m fasting, my “Work Day” basal profile works perfectly without requiring any extra temp basal. It’s pretty interesting…now that I feel like I’m onto something. Thanks, @Eric for mentioning this before.