TDD, Basal/Bolus ratio ... basal perctange is high. Is this worrying?

So, my honeymoon is gone or mostly gone. My insulin needs have risen considerably… I am concerned about the amount.

Currently I take 28 units of Tresiba daily. TDD is around 32-40. That’s right, I generally eat carb reduced (not Very Low Carb though). I weigh 83kg, but have a normal waist circumference, and have been doing resistance training, so I suppose this is mostly because of muscle (at least I hope so :slight_smile: ).

Now, according to the general starting rules, typical TDD is 0.55 * kg body weight. In my case, this would be ~46 units TDD. I’m under that. But, typically, the basal should be no more than about 30%-50% of the TDD. In my case, it is somewhere over 70% !

Is this cause for concern? Or is this simply because I haven’t been eating many carbs? In other words, as the carb consumption increases, does the basal amount also increase, but to a much smaller degree?

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The higher percentage is indeed due to low carbing. Nothing sinister is going on.

If basals are correct, only the boluses will increase, but it is easy for folks to confuse the need to raise basals during periods of eating more than usual. Extended boluses are still boluses and should not be considered basal!


I’ve never understood this basal/bolus 50%/50% rule to make much sense when using a low carb way of eating. When I’m eating < 30 grams/day, my basal makes up about 2/3 of my total daily dose. I think this “rule” arose simply as a starting point for clinicians to use. A few doctors have taken this rule literally and I don’t find this practice useful.

You’re right in your assessment that eating fewer carbs will skew this artificial rule. In my case, using an automated insulin dosing system, my boluses are often reduced and then backfilled later with elevated basal rates. It essentially operates like a combination or dual wave bolus.

The body doesn’t care what label we place on the insulin, it just wants the right amount well timed.


I have never worried about a percentage rule. I just take what works for me. Right now, while eating 300 plant based carbs and very little fat, I take 11 units of Tresiba and 9 units total of Novolog.

Sounds about right! And low carb will increase the percentage of basal because of very little needed for means AND you will have needs after the bolus wears off. I have never had an extended bolus meet all of my needs. Hate that the Tandem will cancel those extendeds if Basal IQ kicks in and shuts me down. Have gone back to upping my basals (2 hrs before the rise) to account for the rise 6-8 hrs later…usually in the middle of the night! Do others do this?

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I don’t pay attention to ratios at all. I never found it makes any difference. I need more basal alot of the time now on thyroid meds, actually I prolly needed it before too but I went through a peroid of low fears and issues. On the pump it is so much easier to just adjust what you need when you need it.

I wouldn’t worry - you need the amount of insulin you need, ratios and percentages are for textbooks, dieticians and CDEs! Are you using Regular/Actrapid insulin for protein when low-carbing? If not, you might find using it will allow you to lower your basal and dose for protein as needed.

I’ll take the contrarian view here and say that I believe if your bolus percentage far exceeds your basals then you are likely eating far too many carbs. That assumes that your basals are correct. Basals should always be established prior to dialing in I:C ratios. Let’s say that more than 75 or 80% of your TDD is from bolus. I contend you are eating more carbs than is healthy. Not only that but your bg’s will likely swing a lot, compared to if you are eating more low carb. that doesn’t mean “no carb”; just lower carbs.

So I think you SHOULD pay attention to your ratios, especially if your control, A1c or swings are not doing well. Ratios are not just theoretical. That doesn’t mean they need to be exactly 50/50.

Note though that it is the basal that far exceeds the bolus percentage, not the other way round. But yeah, you have a point. High amount of carbs means higher room for error. My A1c is excellent though (5.1%), and my time in range (70-150 mg/dL) is 98%, so the BG management is going well.

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Ahh, thyroid induced insulin sensitivity changes! That is a good point. I also have Hashimoto’s, but the thyroid is still okay. However, once it starts to lose function, I’ll need to supplement the hormones, and then I could see fluctuations until I find a stable dose. This would be a good argument for a pump, because these fluctuations inevitably affect the basal rate. Right now I am using Tresiba, and while it is an excellent basal, I’m afraid it will cause trouble with these fluctuations (due to the long dose adjustment period of 4-5 days). I’ve been on the fence about pumps already, so I’ll bring it up with the endo again.

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I wasn’t referencing YOUR situation with my comment, but how I feel it is important that boluses not far outweigh basal.

That’s not my personal experience. My daily basal is 4 units and my bolus is 8 units (67% bolus), while eating right around 100 carbs per day.

The fact you take just 12 U a day kinda makes u an outlier. NOTHING anyone can ever comment on is going to apply to EVERYONE.

IM(humble)O, there are as many “rules” for diabetics as there are diabetics… I take 16 toujeo and 7 fiasp…

IMO, rules are a “jumping off point” (ala Cher, in ‘Clueless’). When one is first diagnosed, doctors have to have some sort of general rules to get one started. As time progresses, adjustments should be made as necessary. You can’t have the doctors treat new diabetics without any sort of baseline or there would be a lot more of us ending up in the ER or worse, in the early phase of treatment.


I have worked with some medical professionals over the years that are all about the ratios. And that is why I no longer see them. The reality to those numbers are they are a guideline, not set in stone rules.
A few years ago before starting a major clinical trial, I had like 8 different basal rates in my pump. The doctors felt I was ready for a reboot. So they looked at my current total daily dose (TDD) and my weight and recalculated. The magic number was .6. So I went to one basal of .6 for the 24 hour span. The only adjustment we made was .4 on my work days. And surprisingly it worked. Of course everyone is different and my numbers over the past few years have changed but I am currently running 2 basals, one overnight and one during the day. I am pretty close to a 50/50 split the last 7 days and average about 130 carbs a day.
So my take away here, is those numbers are a guideline. You need somewhere to start. And these numbers work for many people but of course not everyone. And I will say the less basal changes you have to deal with the easier it is to fix problem areas.
I do think basal changes are a very complicated and confusing issue. For me back the my older pumping days, I had so many that they were bumping into each other. I mean if you have to start a change 2 hours before you want it to take place, you can see having too many make it hard to figure which one is the problem. Just a thought, not saying anyone’s settings are incorrect. I have learned long ago, that if it’s working for you, don’t worry about the “guidelines” or what someone else is doing.