Blood Glucose spikes after Lunch

Hi everyone,
So I have this really annoying BG spikes every time after I eat lunch. Obviously this is not because I take much carbs or have hypo, so was wondering if anyone else experienced something like this and what is the possible remedy?
I eat lunch every day at the same time which is 13:00 PM and I usually try to limit my carbs to 25-35grams. However, it absolutely does not matter if I eat 25 grams or 40 grams after an hour my BG spikes to 14-15. After two hours and bolusing some units it goes back to normal. I tried to increase my bolus units and if during any other meal meaning breakfast or dinner I bolus 1 unit per 10 grams of carb I bolus 2.5 units per 10 grams at lunch. But it seems like I did not increase the units, because I had the same readings with 1:10carb ratio that I have now.
I was thinking of changing my basal rates (I am a pump user) but my endo tried to avoid that and instead suggests to bolus more and give it a week or so. It is quite easier for him to say than for me to do, because it is quite hard to recover from 15s(300s) every day.
Might there be any reasonable explanation for these spikes, I am thinking to entirely skip lunch tomorrow and see how it goes.

Have you ever tried to prebolus? bolus lets say for 20 grams about 30 minutes in advance. If you wanna eat more, you can still bolus afterwards, but an initial prebolus has helped many to get their post meal spikes under control.

Take care


No I have not tried pre-bolus, but usually I eat like 15 minutes after I bolus. Maybe that will do the trick will try next time thanks a lot.

what kind of carbs do you eat? 25g of sugar will spike your bg much more than 25g of vegetables. I find the same thing with myself, if I eat simple carbs like bread or pasta no amount of insulin can keep me from spiking post meal.
going up to the 300s does seem like a huge spike though regardless of carb type, if you are only eating 25-40g. Sometimes people are just less insulin sensitive at different times of the day. For myself its the morning.

Hi Sofie-A,

"after two hours and bolusing some units it goes back to normal" = you're either not getting enough insulin to cover your mid day meal, or you have an abrupt shortage of basal. If you simply didn't bolus early enough (pre-bolus), you'd probably go low from the corrections. In my experience, if I forget to bolus on time, I will get a spike afterward, but it comes back down later once the bolus insulin catches up. If that is not happening and the BG continues to rise or does not come down on its own, you're not getting enough insulin for the carbs you are consuming.

Some possibilities:
1) Inaccurate carb counting
2) You need to adjust your mid day insulin-to-carb ratio
3) High proportion of high glycemic carbohydrates (white flour bread, etc.)
4) Too little basal insulin on board - I think most people require less basal insulin during mid day, but as the saying goes, Your Diabetes May Vary.

You'll need to do some experimenting to determine the cause, and checking your basal by skipping lunch is a great place to start. After that I would double check the carb counts, particularly if you're eating the same lunch on a regular basis.

Good luck!

increase bolus-eating interval slowly (not from 0 mins to 30 mins at once) so you dont get a nasty low before lunch!!
and i would not leave out the whole lunch, instead try more fat/protein in combination with fewer carbs, to slow down the carb-absorption in your body...

Well, certainly 25 grams of sugar is totally excluded. I eat salad,meat and sluce of bread generally. Nothing extraordinary no rice or pasta. I am increasing bolus it is jut not logical that all of the sudden I will need 3:10grams of ratio. I even think maybe there is hypo somewhere.

What are you eating, most people don't truly look at what's in the food they are eating. I have an Organic farm and when I look at what's in processed food items I know exactly why my Blood Sugar rises also so things like cereal in the morning takes awhile to breakdown and the sugar comes out in the afternoon, I have had Type 1 Diabetes for 32 years so I have gotten used to what foods cause the most problems for myself

Hi Sofie,
Since you always seem to spike then maybe it is your basal? I would increase basal and see if that helps and if not, then maybe try to eat a low carb meal at that time, like around 9g with only green veggies etc. for the carbs and protein/fat. Don't eat the bread. I don't know and if this will help or not- just my thoughts and ideas :) The longer pre bolus idea is good too, I would be careful as you can go to low and or miss the insulin peak too.

You can test frequently too if you don't have a cgm to see if you are going hypo.

Does your carb ratio need to be changed? I had the same problem and I thought it was the same thing you did. I changed the basal rates and had better luck. It must not be your carb ratio if it's only at lunch and not every time you eat. Best of luck! Those spikes are the worst.

How does one determine if it's not enough basal or incorrect bolus, if it's high 4 or so hours after meal? Sofie- do you have a CGM? Also, as mentioned, it helps to pre-bolus, if you're not low and don't have a lot of IOB. I also eat more protein and slow carbs first then maybe fruit or whatever afterwards. I think it may help to increase your basal.

I agree with many of the posts above. It's likely either attributed to a misjudgement of how the food reacts with your system, or that your basal rate needs to be adjusted. If you do lots of tests (say once an hour or more) while its happening you'll be able to see the trend, and then using that information be able to adjust accordingly.

You could also skip lunch, again while testing periodically, and watch what your sugars do without adding food into the mix. If you naturally climb without any carb intake then for certain your basal rates will need to be increased for that time period.

I went through a similar thing through the night. After dinner I would go high, and then while I slept I would always end up with a low. With a bit of logging, and detective work it was an easy fix by adjusting the basal rates before dinner, and at midnight to compensate for the shifts. :)

Yes, I am aware that miscounting might cause spikes, but it is strange a bit that I count perfectly fine for dinner and breakfast and only make mistake during lunch. I usually eat high protein and low carb (like slice of bread) as I said 25-30 grams of carb is max. for lunch. I am avoiding pasta or rice at least for now until I figure out my dosage. I would love to go all organic, but quite honestly with my lifestyle that would be much of adjustment for now, but maybe one day )

Update: I skipped entirely lunch today (not fun at all) and my BG seems perfect(tested every hour), so now I am 100% certain it must be my carb insulin ratio . Or do you guys have any simple carb lunch suggestions maybe?

I am an Organic Farmer but I don't think Organic cures everything. It would be nice if our Doctors could spend 24 Hours with us and than change our dosage, yeah I know, a Doctor in your home for a full day - right. I do use Novolin R & N because its just easier for my body to balance, my Doctor complains that other types of Novolin would work better but my Blood Sugar is balanced really well so this is just what works for me.

By skipping lunch you just did a basal test, and confirmed that your basal amount during lunchtime is good. So I agree that it must be your carb/insulin ratio that is wrong. BTW, it isn't unusual to have different carb/insulin ratios throughout the day. Personally I am twice as insulin sensitive (double the carb/insulin ratio) in the morning as I am at night - the only way to figure out what is right for you is to keep testing.

The next thing to do is to try to eat the same amount of carb every day for your lunch meal for several days. So eat the same number of slices and type of bread every day and see what happens as you vary your bolus amount and timing. Don't worry about what your carb/insulin ratio should be - just figure out how much insulin it takes to keep your BG level. THEN go back and divide the carbs by the number of units of insulin you took to figure out what your carb/insulin ratio REALLY is, and use THAT.

Once you've done that you can either stick with the meal you've found, keeping the carb constant but varying the meat/cheese/nut you eat. Or you can apply your tested ratio to different meals with different sources and amounts of carbs, which takes more testing but is certainly do-able. I combine these techniques: my typical lunch meal is at work, and I buy bread with the same carbs per slice to make things easy and predictable. Weekends or going out for food requires more effort. A recent trip to Japan, where I was eating out for every meal (and eating foods I sometimes didn't even recognize) definitely took more effort and more BG tests, but was a lot more fun than eating a can of tuna every day.

(BTW, you should buy the book "Pumping Insulin" by Walsh and/or "Think Like a Pancreas" by Scheiner which describes this all in detail).

Great reply Jag, summed up what I would have written.

Thanks a lot for your reply. I will try to stick to the similar food, I did use the same grams of carbs for lunch, but did not really think of eating one and the same thing, maybe that will do the trick.
I will buy the book, thanks again for suggestions.