Ratio of Basal to Bolus

I’m trying to get information on basal to bolus ratios. Several times, my HCP has said that my basals are too high given the amount of bolus I take. (This with a fairly flat line, averages under 110)

She states that the ratio of basal and bolus should be equal - that if I take 20 units of basal per day, I should have 20 units of bolus per day to cover my food. When I pressed, she could not give me a reason, except to say I was in danger of hypo episodes by running so low and depending too much on basal.

I eat a very low carb meal plan - usually under 30 per day.


This is often a rule of thumb measure used by some offices. It is often used to reinforce that to much basal insulin can have some difficulty. I take pretty close to 50 / 50 but that rages everywhere from 30% bolus and 70% basal to the opposite. I obviously do not know your typical dosing, but unless it si completely out of kilter I think I would grin and say “yes I have heard that”.

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I think following this rule of thumb is not helpful. The real goal should be to make sure that your basal rates keep your blood glucose line relatively flat through the night and if you miss a meal. The basal rate is intended to metabolize the glucose output of your liver only, no more, no less. I fiddle with basal rates regularly.

Basal needs are what they are and vary from person to person and even change from day to day in the same person. I’m sure they vary by age, gender, season, other illness, and a myriad of factors.

If you eat a low carb diet then you’ll take less bolus insulin than someone who eats more carbs. That’s a simple truth. Your ratios will be whatever they are and to try to makes changes based on this philosophy is silly.

Right now my basal to bolus ratio is about 42/58. I pay attention to much more important numbers like time in range and time spent hypo. I spend 84% of my time in range, 65-140 mg/dl, and less than 4% of my time hypo. Why would I want to add insulin to my basal rates to mindlessly adhere to this artificial notion and gain weight? And it would be just as silly for me to propose that all insulin-using diabetics follow a 42/58 basal:bolus ratio becasue it works so well for me!

I would either just smile and nod when she brings this up or challenge her to show you the science this idea is predicated on.

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The 50/50 notion is utter nonsense. It is not any kind of goal in its own right for any reason.


If I had to take 20 units bolus to match 20 units basal I would be in BIG trouble. My thoughts are that you should disregard this statement and do what works best for you. I use a lot more basal insulin than bolus insulin, and I don’t struggle with lows, highs, or food / weight issues, and I don’t follow a “low carb meal plan” - whatever that is (LOL). As others have already said, that basis is nonsense.

Do what works for you, wonderwoman.

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bolus/basal ratios are going to vary for a number of reasons, the first one being it depends on how many carbs you eat. The more carbs you eat, the more bolus you will use. Sometimes basals haven’t been properly determined, and then the person will compensate by bolusing more when they do eat. Setting basals properly involves skipping a meal–see your manual that came with your pump. Many folks will find that if they skip a meal, their bg’s go high–that’s because they are relying too much on 3 or more boluses to even things out and when they miss a meal, they don’t bolus, and then their bg’s climb. And there are a lot more variations on that theme.

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Whatever works for your works. I have also had drs talk to me about that magical ratio. I just ignore them.

I take about 35 units of basal a day and typically less than 10 (sometimes a lot less than 10 of fast acting). My latest hba1c was 5.4 (too high for me, I prefer around 5). I don’t go low and the basal is what holds me where I need to be. I do mostly eat very low carb. And the days I have close to 10 units would be those when i am not sticking within my usual levels.

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hi! i agree with all of these replies that the ratio thing is rubbish, do what works for you. i have always used a lot more basal than bolus. right now im on 18 units of basal a day and MAYBE 2 or three fast acting units. i eat moderately low carb and exercise like 3 times a day, commuting to and from work by bike and doing my workout. it seems with the exercise and low-ish carb, thats the way it works best.


Yepper. :expressionless:

I used to pay at least some lip service attention to my basil:bolus ratio because 50/50 had been tossed in my general direction and I just went with it rather than thinking about it. In hindsight it appears to me to be a “rule of thumb” which stops working if it is applied too far out of the context it was originally intended to be used in.

In this case, I think the key to understanding the 50/50 rule of thumb is that it assumes one eats the amount of carbs in the standard (?) diet plan a diabetic is typically told to follow. But when someone is intentionally reducing the amount of carb in their diet then that rule of thumb won’t work.

Try pointing that out to your HCP next time and see how the discussion goes. Also try to focus the discussion more on the clearly sensible goal your HCP implied of avoiding hypo episodes caused by setting your basal rates too high.

What can happen … and what 50/50 is supposed to help detect & avoid … is that someone can be using their basal insulin to help cover the total amount of carbs they eat. In other words, their bolus carb:insulin ratio is too low but they have fudged around this by increasing their basal rate rather than correcting the bolus ratio.

If this is the case then obviously if they miss a meal their excessive basal insulin is going to pull them into a hypo. But 50/50 won’t work correctly in your case because you are limiting the carbs in your diet. So in your case what you and your HCP have to do is go back to the first principles to verify that your basal rates and bolus ratios are working correctly.

I assume you are probably pretty much doing that already. If not, it’s something to of course take a look at. But you’ll have to do that by the old school way of basal rate testing. Trying to do the 50/50 thing would only screw you over. Big time. :open_mouth: