Is there such a thing

Assuming that you don't go low, is there such a thing as giving too much for an insulin bolus for a meal that you will eventually come down in BG?

I'm only 6 months into a T1 diagnosis, and was wondering when dealing with "problem" foods if giving a lot more insulin then how many carbs you think is in something is bad (assuming your blood sugars don't go low). Or is it better to give the same bolus (assuming your blood sugars eventually come back to normal 5 hrs after a meal) but just change *how* you bolus (ie try playing around with the dual wave parameters)?

For example, I know that if I give myself x amount of insulin for a particular food that I am confident with the carb count I will have normal blood sugars by the next meal. However, my blood sugar will run in the low-mid 200s for a few hours. Do I just leave it as-is, give as much insulin as it takes to lower that curve (while preventing a low), or play around with a dual wave?


The goal should be to be back to normal range as soon as possible, without lows. Coming back down 5 hours later before the next meal is too long for me. So, it's not too much as long as you're not having crashing lows. 200's after meals isn't good period & do what you can to head off that spike. Bolus timing is just as important as dose & takes as much trial & error experimentation.

We do a lot of messing around with insulin boluses, there are so many variables to contend with, my son rarely takes a straight bolus regarding only the carb count. Like giving him a big correction and meal bolus at say 200BG and he might not eat for a hour or two until his cgm is in the low hundred. If there is no time to pre-bolus, say on a school morning, I may suggest over-bolusing him and tell him to keep a good eye on his cgm, he always has snacks close at hand at school and loves the opportunity to eat in class, teen after all. But it usually still doesn't drop him low by lunch unless he's decided to correct too at the 2hr mark. It's all of course safer with a cgms or testing a lot. Hope you get more responses.

While we are taught that a carb is a carb, in life, nothing is every so simple. I think many of us will find that different foods affect us differently. For instance I seem to be more sensitive to wheat than to other grains. So on the rare occaison when I might have something with a bunch of wheat I probably double bolus for it.

You want your bolus to "cover" your glucose load. If you know your meal will generate a higher glucose load, then you should adjust your bolus. I think each of us works with different goals and insulin will have different effects on us. I tend to keep my blood sugar < 140 mg/dl, I eat low carb and my insulin boluses are not strong enough to create harsh lows. I hardly ever "correct" and when I do, I can correct at 2-3 hours without too much worry about the possibilities of lows.

But one must remember, most rapid insulins last upwards of 5 hours. At 2 hours, perhaps half the bolus from your meal has still not taken action. At 2 hours you cannot distinguish between an error in the bolus dosing and an error in the timing profile. This is important because if you simply mistimed your dose, stacking a correction on top can cause a hypo you don't want.

So the other subtle thing I have had to learn is how to adjust my expectations for meals which take longer to digest. Meals that are primarily protein or fat based and can take longer to digest and at least for me meals of large volume take much longer to digest.

It's really all trial and error when it comes to determining the insulin requirements that your body requires for different types of food. Nothing is as one-to-one as it appears, and your normal everyday carb ratio may not be sufficient for certain types of foods.

In this case you have to use your judgement to adjust your requirements, which in the end is a guessing game - especially when eating out. So make gradual changes to how much you bolus, and keep track of the type of food - then test to see how close you were. If you're still running high, then next time you know that you need to give yourself a little bit more. If you're low - then bolus less.

If you aren't dropping low, then you are only giving yourself what you need. Remember that insulin stays active in the majority of peoples system for 4-5 hours, so in most cases it can take awhile to bring yourself back to normal levels without going low.

The trick is to find what works for you.

To answer your question:

Theoretically, in a T1 anyway, food is matched to insulin in such a way that a hypo means you've taken too much insulin and a spike means you haven't taken enough.

But as others have said, there are a gazillion factors that affect that relationship by sending BGs too low or too high for any given amount of insulin. Shooting for normal BGs 2 hours post-meal is probably the rule of thumb. MDs will tell you to keep your post-meal spikes below 180, but you'll find a good number of posters on this forum shoot for much tighter control.

How do you do those things? Well, you've seen some strategies posted here. For your insulin dosing, dual wave bolusing is a good tool to have. You can adjust a dual wave to treat higher than desired postmeal spikes and subsequent crashes, or vice versa. You'll probably have to adjust basal dosing as well, and if you haven't done your basal testing, I'd strongly suggest doing that.

Best wishes!

Thanks, Gerri!

So much to think about when you are the mom of a person with type 1! I congratulate you with all of your planning, hard work, and team work with your son :) I love having a cgm; it makes me braver with trying new way of bolusing or increasing my doses. I've also noticed that it is better for me to give extra insulin from the start then to try and correct a little later on.

Thanks, "bsc"! I've seen your feedback on other discussions and it is always very informative :)

One of the tough things of being newly diagnosed is breaking away from the mentality of "Doctor knows best". My endo was ok with me being in the 250s for hours after every lunch meal because I came down at the end. That was unacceptable to me, as I was having problems concentrating and thinking clearly. Eventually, I ignored his recommendations and just starting bolusing more. He was worried that I'd go low, but I was just fine!

It is just still a bit scary for me to give twice a bolus as what I think it "should" be. But I have a Dexcom, monitor it often, and have been very successful so far. Your post and others give me more courage to do what I need to do to bring my BG down, even if it means giving a much larger bolus.

I now eat my "risky" meals when I'm not working, and eat lower carb during the work day or when I'm traveling. My thought is that if I can't do something about it (like exercise if I get too high), then I shouldn't be experimenting at that time.

The Dexcom is fantastic for showing you how you metabolize meals differently! I have a once-a-week treat (cheesecake) and metabolize that so slowly that it is striking! So I now give 50% upfront and 50% over 2 hrs (which worked the last time).

I wish there was a way of feeding in our Dexcom profile, and having a formula spit out for how to bolus for it!

Thanks, Richmatik! Your last sentence really is the tough part of having diabetes! That is really the #1 thing that new people need to know!

I'm kind of inclined to think that a carb is a carb.

I think that having rates and ratios set precisely can make a huge difference and impact the probability of succesfully procesing larger foods. I have sort of developed a lifestyle where I eat maybe 30G of carbs between breakfast and lunch and usually eat about the same thing every day. Every few months, the numbers will seem to "drift" a bit and I'll see where the "spikes" (considering 140 something to fix...) or "bulges" (fasting numbers drifting higher than I want...) and usually just adjust which every bolus ratio or basal rate up or down for the offending time period or, if it's more than one, or a seemingly longer period of elevated BG, I'll consider adjusting both but I usually try one "click" (+/- 1G carb/U or +/- .05U/ hour rate, the smallest adjustment I can make...) and see how it goes. A lot of time, that's all it takes to get the rate/ ratio more precise. If you have a 10-1 ratio that should really be 9-1 and you eat say 60G of carbs, you'd end up with 6U instead of 6.67U and be "short" which would lead to a rise. If the numbers are off or the food is bigger, the variance can be more pronounced? I would have probably laughed at the suggestion that little numbers could make a significant difference before I had a pump but I seem to have things set ok these days and can get decent results a lot of the time?

Hi Annie,

Sounds like you're doing great..good job. I do the same thing, when I'm trying different ratios, foods, I do it when I'm not working, home on the weekends, with someone, etc...I tend to believe too that a carb is a carb, I'm finding I can really eat anything i want, a piece of bread vs. a fruit, vs. a dessert doesn't really matter as long as I get the correct insulin and timing right. Doesn't matter, a carb is indeed a carb and making just a very small maybe 1/4 - 1/2 unit adjustments makes all the difference or waiting maybe 15 minutes after bolus to eat makes the difference. I too have been really nervous about taking too much..but I've overbolused purposely when I was a bit high or unsure on carbs, tested and I was OK. I think it just takes, as mentioned, trial and error and once you get more used to it, you'll feel more comfortable. I bolused nearly 4 units (still on MDI's) the other day for a meal, the most I've ever done for one meal, was really scared but it worked out great and ate an english muffin sandwich. Baby steps with this. Try, if you can, to get your numbers below 180..and certainly staying high for 5 hours isn't the goal, IMO, because that could mean too your basal is off and you'll just end up having to correct for your next meal too, spiral of just doing corrections all day.

Are you pre-bolusing before eating? Ideally, a meal spike occurs 60-70 minutes after bolusing and comes down within half an hour or so. At some point, you might like to do a search on this site for the "super bolus" which you can do with a pump that allows you front-load insulin to bring a meal spike down quicker without causing a low later on. With Dexcom helping, it might work well for you.

ah..thanks for this, don. my endo mentioned this the other day as I'm starting my pump next week, recommending I do a quick (or super) bolus, to make sure my pump trainers show me how to have all my bolus 'up front' and/or not extend it as I tend to spike quicker and then fall. i'll research that as well. good info! :)

W/ the superbolus, you cut the basal after you eat and let the bolus work as basal too? It's kind of a clever idea. W/ a CGM, you can sort of hedge your bet and see how it's playing out in an hour and nudge it one way or the other? Very handy!

great...load me up...let me eat, yahoo!