Coffee and BG spikes

Hi Everyone,
Im a recently diagnosed T1, transitioned from T2 about 2 years ago. I’ve been pretty pleased with my morning numbers, but I do notice numbers rising almost as soon as my feel touch the floor. When I drink my morning coffee my BG spikes almost immediately and sometimes its harder to get it down. I’ve switched to half caffeine/half decaf but doesn’t seem to make much of a difference. I really, really like coffee so I’m not inclined to cut it out entirely. Any tips for working with coffee? My endo said to dose an extra 5g carb to adjust for it, but I like having a cup when I take up, dose after that for breakfast and another cup. Not sure if it’s a timing of insulin issue or not? Thanks as always for your help.

It’s not unusual for numbers to rise when you start moving around. As for coffee, caffeine can do that. It’s my understanding that decaf still has some amount of caffeine in it - maybe not enough to keep someone awake, but it might affect the numbers. I find 17g works fairly well for my KCups but that’s me - you’ll need to do some trial and error to see what works for you.

Hi Diane @DFBB!
Coffee always spikes my blood sugar. It doesn’t matter if it is fully caffeinated or decaf. I usually give myself 2-3 units of insulin right before I pour my cup. If my blood sugar is rising I add my correction dose to the insulin for my coffee. So, if I am 80 when I wake up and I notice that my blood sugar is rising I will give myself 2 units for my coffee and another 2 or 3 units to catch the rise (total 4-5 units). These numbers work for me, but I came to them through trial and error. I would start small and increase your insulin gradually until you find what works for you!

hi @DFBB a persons without T1 will dump sugar into their bloodstream when they first wake up, because it helps them wake up. In T1 where we have to manually add insulin, we call it “dawn phenomena”. there is no good answer to this , so polling the community may confuse the heck out of you. What works for you will depend, completely, on you and how you prefer to deal with this. That being said… I trained myself to eat right out of bed. I take more insulin per carbohydrate and I have mu pump deliver more basal in the morning, right up to noon, to help compensate for the early morning spike thing that almost always happens. I have reasonable good results with my pump and reasonably good data by watching my CGM. good luck!

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Thank you all for your replies and ideas. I’m quickly learning that managing T1 takes a lot of trial and error, I guess I have been hesitant to do some of my own tinkering which I’m now seeing is necessary. I appreciate the support and help from everyone.

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As @homeschoolingmomof5 said, it’s best to start small and work to (or down). All the best to you!

I agree with everyone else here and want to encourage you to tinker on your own. It is really hard to get good control if you don’t. We are all our own individual experiment. Keep notes too as it is sometimes hard to remember exactly what you did. You might like reading “Sugar Surfing” by Dr. Ponder.


Another good book is Think Like a Pancreas by Gary Scheiner. He has Type 1 and works in the medical field.

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Hi, I didn’t realize until starting a CGM that morning coffee spikes blood sugar levels and my endo explained that’s because it’s a stimulant. I adjusted and began dosing upon waking, then having coffee, followed by a light breakfast (plain yogurt & fresh fruit). As everyone said, it’s trial & error - this has worked well for me.
Btw I also switched to Tresiba insulin from Levemir a few years ago, and that has completely ended the ‘Dawn phenomenon’ I used to suffer.
Good luck !

Yeah my sugars rise the second my feet touch the ground too! If I have coffee before breakfast, I need to take a small amount of insulin (I need this regardless if I push breakfast out too far). Otherwise the only thing that works for me is to have my coffee with breakfast. I don’t actually bolus for the coffee but my foot on the floor rise stops as soon as I eat so once I pair my coffee with some eggs and toast I don’t need to dose but for a cup of plain coffee I do. One of my friends who is a nutritionist said a scoop of collagen in their coffee stops blood sugar spikes for some T1D. I haven’t tried it and obviously am not qualified to make that statement but just something that was shared with me

My personal experience is that coffee does not raise my blood sugar. I drink 2-2.5 cups every morning, with unsweetened soymilk. I do have rises in the morning, however, which I attribute to the dawn phenomenon. They start around 4:30 and go to around 9-10:30. They are very variable, and depend on how well I bolused for dinner, and how well I corrected before bed. Sometimes I don’t get any rise at all - I just attribute that to whatever unknown hormones/other variables are going on in my body I’m ignorant of. If I’m over 100 when I check my blood sugar in the morning (usually I wait til around 10:00 to do this), I take a correction dose (105 would need a very small amount - maybe 0.1 units).

What I’ve read is a lot of correlation between dawn phenomenon, blood sugar rises, and coffee drinking, so is it just correlation, or are there causal effects? To sort this out for yourself, probably the best thing is to not drink coffee in the morning, or every other morning (hard, I know), do this 10 times or so or whatever seems best, and see what your blood sugar does when you don’t drink it That way you can control your variables better and get a better idea of what the caffeine itself is doing, if anything.

Thank you all for your ideas and guidance, I have started giving myself a unit or two depending upon my fasting number, waiting for 20 min to drink my first cup of coffee and so far is working better for me. I feel like it keeps me from going into breakfast chasing a higher BG. Thank you for your support.