After breakfast high blood sugars

T1D for 14 years, still struggling at times with understanding what is going on with my sugar levels. Recently, 6 weeks, I’ve been having extremely high sugars 3 hours after eating breakfast over 250 to 400. For breakfast I check my sugar and then eat, followed by taking my insulin. Then when I’m ready to have lunch or when I’m feeling high, I check my sugar and need as much insulin as I shot for my breakfast? I’ve also noticed I’m struggling with being tired, sleepy, lethargic for the rest of my day. Can anyone offer a suggestion or solution as to what is happening? Thanks in advance!

@Glimmertwins Welcome Terrell to the JDRF TypeOneNation Community Forum! As you probably already know, this is a community of people affected by diabetes - very few of the members are “medical professionals” and offer observations and suggestions based on personal experience - not Medical Advice.

My T1D has been for 66 years and at times I’m still baffled by some of my glucose levels. The “tired, sleepy and lethargic feelings” reflect much higher BG [body glucose] level than what your body has become accustomed to. Three hours after eating breakfast, I expect and hope that my BG is within 50 mg of my lunch time target and want my BG on target before eating lunch. Assuming you are eating the “same” breakfast foods and quantity as before can see a couple of places you might look:

  • Dawn Phenomenon: this is a normal and expected event where your body releases stored glucose to help you get the day started - as your body ages, probably more start-up glucose is needed. I suggest that someday, you skip breakfast and insulin and check BG every hour and see what happens - you may need additional injected insulin.
  • Insulin Timing: try taking your insulin BEFORE eating, maybe up to 15 minutes before eating - depending on the type of insulin you use.
  • Body Change: over time your body has been changing, and this includes the amount of insulin needed for all grams of carbohydrate - your meal-time I:Cr [Insulin to Carbohydrate ratio]. I used to take 1 unit of insulin for every 12 grams of carb eaten [1:12], lately I’ve needed 1 unit for every 8 [1:8]. Over the course of the day my ratio varies - for breakfast 1:8 and for supper 1:18.

Your body, just like everyone’s body changes over time - those of us living with diabetes and others. Try not to feel “different” just because what used to work for you doesn’t appear to be working now - you will find many people living with diabetes have needed many changes in insulin over a period of time. And, of course consult with your medical provider - there are many causes for high BG other than lack of insulin.

Hi @Glimmertwins and welcome to the forum! My first thought about the post-breakfast highs is that you need to check your carb ratio. Those do change from time to time and it doesn’t mean you’re doing anything wrong - just that your needs are changing. When my numbers are high I get tired as well, and if they’re over 300 (that may not be your number) no amount of insulin will bring them down until I wash any ketones out of my system. Even if don’t check for them I find drinking a couple of glasses of water or other sugar free drink does the trick - but it can take a few hours and it is like watching paint dry.
There was a time when we were instructed to take our insulin immediately before we ate - or very shortly after starting. Now some insulins are meant to be taken 15 minutes before, and some loop systems advise that as well.
Figuring out which changes to make can take some time - not to mention trial and error: so adjust one thing at a time and wait at least 3 days to see how it’s working. And small changes can make a big difference when it comes to insulin dosing so take it slowly.
Looking forward to your contributions!

@Glimmertwins ,
Have you gotten up and skipped breakfast to see what will happen to your BG? Mine will spike shortly after I get up, even if I eat nothing, I bolus for my coffee, even if I put nothing in it, but a splash of almond milk. I’m also careful to count the carb I have for breakfast too. I had to stop eating any kind of cold cereal for breakfast, as it spikes me too much. I just can’t control BG with cold cereal.

Do you wear a CGM? That helps me see a sharp rise, as it alerts me when it first starts.


hi @Glimmertwins welcome to TypeOneNation, I swear my body is like an old rechargeable battery sometimes I get a spike for absolutely no reason at the same time (for me it was after lunch last 2 weeks). One thing to also take a look at is what are you eating for breakfast? if its something like cereal, maybe switch to a super low glycemic breakfast or if you are eating zero carb like eating ham and coffee, maybe adding toast with peanut butter (mixed carb?) sometimes all I need is change.