Tandem control IQ What to do if you forgot to bolus for food

Hello all.
54yrs TD1,
New to control IQ.
Great TIR- like 91%, so I’m thrilled.

But, my excurions high occur at times that i “grab a taste of that treat sitting there”, or testing the flavors as i cook.
Things i forgot to program until i run over 200.

I get myself into trouble dosing then wth over treating. I see the IOB is higher than my last bolus would account for, but have to look at the tandem app on my phone to see what was done, so i often just go by the pump since i have to have that out to dose.

Any guidance here?
Thanks for your help.
Be kind. Im new to this tech. Never did get my Samsung watch4 LTE to display dexcom. Ugh, another day for that


I, among a number of others here, will bolus aggressively with the intent to treat the inevitable low that will follow.
I think it is really about how bad do you think it will get.
I have completely forgotten to bolus for a meal, and control IQ responds by ramping up my basals to eventually bring it back down.
If it was a big mistake though, I get aggressive with a large bolus, and then plan to eat a few more carbs when my BG gets back into a normal range (eat before you get low, that way it will slow the drop and help ease the curve at the bottom.)


Instead of over-treating, consider doing a super bolus, which delivers what you forgot a little late, but sooner. . (John Walsh “Pumping Insulin”)

Set a temp basal to the minimum for 2 hours. “Borrow” the not-to-be-delivered basal and add it to your bolus. More insulin will be delivered quicker to handle the food spike, and 2 after hours the total delivered insulin will be the same.

This is also useful for corrections to post-meal highs that stay high for much too long, but eventually come down to where they should be . Like pizza for dinner.


It’s not Control iQ specific; the problem arises with any system that auto-corrects based on blood glucose. Without the auto-correct it is easy; just bolus for the food late. I do this all the time with the Omnipod Dash system, but it won’t work with the O5.

FWIW (off topic) with non-auto-correct systems the approach is to bolus for the meal without doing a correction, wait five minutes, then do the correction. In the Omnipod this means doing a bolus without entering BG (which boluses the full meal amount) then going back and doing a correction; the Omnipod (from the Eros onward) assumes the carbs go in instantly and calculates the correction based on the total IOB (with some tweaks), so the correction always comes out negative unless a big one is required.

With auto-correct we have already received a bolus for part of the meal in the correction. Doing the full bolus is too much. The highly inaccurate fix is to guesstimate how much of the bolus was already delivered (in the bg correction) and subtract the corresponding amount from the carbs entered for the bolus… Too much head arithmetic, but it’s still probably as safe as the over-bolus from doing the full amount.

When, eventually, they get round to taking account of the time it takes to metabolise the carbs; so we have carbs-on-board as well as insulin-on-board, the problem disappears because we just enter the carbs with the original time of ingestion (i.e. when we chowed down). Of course that requires some serious computer programming; developing a good model of carb adsorption based on observed BG, so it might take a while.


Temp basals aren’t possible on closed-loop systems. In practice temp boluses aren’t either, although I’ve seen heated debates on this. The correction is both a temp basal and a temp bolus.

Of course it is possible to disable the loop for a while and DIY; this is always an option but for those of us who want closed loop systems it’s an admission of defeat.


With a truly closed loop system you wouldn’t have the problem described. It would not need to have food information added, but just monitor and respond to the BG level.

btw - A “temp bolus” is either nonsense or redundant. Every insulin bolus is unique and either a short time delivery event or and extended time one. Both are temporary.

A temp basal is a temporary basal adjustment. How you achieve it depends on what specific tech you have, but the original question was posed by someone using Control-IQ which DOES have a setting for a temp basal rate. (page 77 of the Control IQ User Guide. Basal-IQ has this also.)

With Control IQ (which is partially-closed loop with a gaping hole, if you are a living organism) you would set the basal to whatever the minimum possible, which is 0.1 unit/hour, and set a reminder with an app to restore it later. If your basal rate was 1 unit per hour, and you wanted to add 2 units to the pump’s calculated bolus to bring the peak down faster, you’d set the temp period to ~2.2 hours. Tandem software will complain about your setting the basal to less than half the base rate - but it will do it.

I did it this morning with Basal-IQ* to bring my post-breakfast peak back down under 180 in half the time. An hour and a half later, the level was where it would have been if I hadn’t done anything. Instead of a smooth up and down curve I got a mountain with a plateau on the down side that lasted until the basal delivery went back to normal. (*I’m vetting the system and tweaking the parameters before I try Control-IQ)

There’s a fundamental problem with entrusting an idiot level system with mechanical components with your life. Imo, only children and the senile should not expect to treat their own diabetes consciously. They need caregivers who will.

Want? I want somebody to tinker with some of my t cells and build me a biologically compatible replacement pancreas and reprogram my immune system so that it doesn’t attack beta cells and I don’t need rejection medicine.

We don’t have a closed loop system.
Wishing and cursing reality doesn’t change the fact that we need to be able to use the tools we have. That requires thinking and accepting compromises and workarounds.


In 1969, i was told a cure was around the corner, and that there was hope beyond imagining.
But the ADA brochure that they gave me that first day, at 17, was that i would die before 30.

I hope that all of us reach nONE as a reality soon enough. Either as a natural cure, a tech accomplishment to mimic the human cure, or a tech bridge to that day.

1 Like

A temp basal cannot be set with Control-iQ. See the comment at the bottom right of page 77, also note that the minimum rate is 0 (as with Dash and O5.)

However I was not suggesting that your approach is in some way bad; indeed I personally think that doing a bolus, including a super-bolus, and turning the basal off completely may be the best approach for people who use higher basal rates.

My point was, rather, that doing this means turning off the auto-basal features with both the O5 and the Tslim-x2 (i.e. turning off Control-iQ).

Sorry, I meant “extended bolus”.

That’s what C-iQ and the O5 do when no bolus is delivered. It would work if the insulin got adsorped at least as fast as the food; BG would go up a bit and then C-iQ would kick in and correct it and the elevated rate of insulin delivery would cover the incoming food. It’s like covering a meal with an extended bolus; I do extended boluses from time to time to cover protein.

I’ll experiment with the O5 when I get one to see if I can manage some meals this way but in general it seems that people who loop still need to bolus to cover “fast acting” food.

This is what I meant about modeling food adsorption rate based on BG rise but I can’t see a way of coding that without some information about when and what food was eaten. I believe the code has to deliver more insulin than a simple correction calculation would suggest.

-Before I forget, the OP should turn on missed meal reminders. A servant that worries and sometimes nags needlessly is better than one that doesn’t pay attention to your potentially dangerous omissions.

You must have a different version Tandem manual. What does it say on the cover and page 3?

In the Control-IQ manual that I downloaded 2 weeks ago, version 7.4 mg/dL, page 77 has no note there. I searched the manual and found no description saying that a temp basal rate was only possible if you shut off Control IQ, or would interrupt other features of Control-IQ, nor does it make sense that it would. Because it is a rate not a guaranteed delivery amount, Control-Q should still be able to suspend it if needed, just as it can during sleep or exercise.

If you shut off Control-IQ it couldn’t do anything. That could be worse that a late entry of a meal bolus. It’s half-hearted automatic correction boluses (they are not full corrections) are better than nothing.

Page 77 states that the rate can be set to 0% of the current basal rate, but not below the minimum allowable rate of 0.1 unit/hour, and if you attempt to set less, it will override.
The note at the end of section 5.9 describes what happens when shutting off insulin interupts a temp rate.

In your own screenshot 2022-04-26 12.35.34 on the page numbered 77, in the right column just above the blue bar in the right margin, it says

[blue] [flag icon] NOTE [/blue]
In order to use Temp Rates, Control-IQ
technology must be turned off.

1 Like

I’m sorry. I must be getting senile. I was looking for a note " bottom right of page 77".

The note in the same section of text in the Basal-IQ manual is worded differently, so I was ignoring it. If I had written that manual I would have put a note that said when you couldn’t use a feature at the start of the section describing the feature.

I’m going to look at that setting when I get Control-IQ sw and see what it does when Control-IQ is enabled, if it’s blocked with a warning or setting it triggers a warning. It should do both (but imo, neither should be necessary. ) .

It’s not the first thing I’ve misunderstood or not understood why software doesn’t do what it could or should. The last one was the Tandem Basal-IQ bolus calculator not automatically populating the BG field to suggest a correction. I asked the trainer. She knew it was a problem but just accepted it as normal. I don’t get it.

The manual I looked at (which I had just downloaded again - my previous comments were from memory) is:

Software Version: Moonlight (7.4)

and the bottom right of page 77 has been rewritten slightly in that they added a bold note (the blue highlight below is just because I had the text selected):

Eh? Control-iQ controls the rate (that’s the point). So if you change it Control-iQ no longer controls it so Control-iQ has been overridden.

That’s not what it means, adding some emphasis:

If you program a Temp Rate greater
than 0% but less than the minimum
allowable basal rate of 0.1 units/hr,

0 times anything is always zero, so if they had wanted to limit the minimum (like the old Eros pods) they would have only allows values in the range 1% to 250%.