How does caffeine affect diabetes?

I drink a lot of Diet Coke & coffee, and I can understand that coffee would make my BG rise because of all the sugar and creamer.

But I’m trying to find out if caffeine is good or bad for diabetics, and I can’t really find anything specific pertaining to type 1 diabetes online.

I have a lot of high BGs… a lot. So I’m gonna cut out caffeine for this week and see what happens. I’m sure if I stop eating so much junk food that would help too. :wink:

Your opinions would be greatly appreciated though!!

Its confusing and ironical that several studies have found that coffee drinkers, especially those who drink a lot of coffee, have a lower risk of diabetes than do other people. However for people with diabetes, drinking coffee or consuming caffeine in other beverages may make it harder for us to control our glucose…Im not really a caffein drinker but whe I inquired to my doctor about drinking coffee…She suggested decaf. =)

How about drinking coffee, and not some milk/sugar/espresso drink?

I drink alot of coffee, and it has little to no affect on my blood sugar levels; no sugar, no cream, no changes in my blood sugar.

Black coffee or diet coke (or my new favourite coke zero) has no effect on me. About once a month somebody lectures me on the evils of coffee/caffeine, but there’s little “scientific” evidence against it, and my own experience is that it’s ok for me. Besides… I’ve gotta have some vice

I drink things like AMP (Sugar Free) and I will usually have to wait a couple hours before I eat anything, and those drinks are LOADED with caffeine, so from my own experience, caffeine does make my sugar very sensitive for a bit.

Unless you have issues with high blood pressure or high levels of stress caffeine, in moderation, should be fine and should not affect your BG.

This could be from the amount of caffeine, not necessarilly from having caffeine. Please be careful as I have seen patient’s come in with cardiac issues related to these drinks.

Drinking lots of caffeine is far less likely to increase your blood sugar than not taking enough insulin to balance the carbs and other calories you eat!

Most of the data I’ve seen relates to pre-diabetes (type 2) and type 2 diabetes and caffeine.

If you want to limit caffeine, go for it.

But to find a more reasonable explanation for your highs, start checking your blood glucose before you eat and 2 hours after. Did you take enough insulin to stay on target? Of course, lots of other things–such as stress, illness, lack of exercise, overtreating lows, poor absorption of insulin–play into highs. But adequate insulin for the food a person eats is the first thing I wonder about. Best wishes!

I drink coffee with creamer and artificial sweetener and I have a hit or miss effect on my BG. sometimes two or three cups are Ok…sometimes I check after two and all is really bad…Anyone find a creamer that is not bad?

I haven’t put either sugar or creamer in my coffee for years, since my first cup in 1948 working nights, and I am a moderately heavy drinker. The PHDs giving continuing education courses on the brain and its problems say coffee has some great antioxidants. They also say the process by which coffee is made decaf interjects some toxins. So I love my real coffee, and i have never found my BG up due to it.

One problem with caffeine is it dehydrates you: and a dehydrated diabetic will see a rise in blood sugar because its more concentrated and because caffeine doesnt literally give you energy-- it stimulates glucose release from the liver.

There is no such thing as a free lunch, and with caffeine there is no such thing as free energy. The energy it gives you accumulates an energy debt that you have to payback at some point or another-- hence the crash.

One thing us Type 1’ers ignore is the importance of drinking water. Your sensation of thirst may have gone away a long time ago, but that doesn’t mean you aren’t dehyrated. Water water water, I say.

Caffeine in coffee raises mine. Caffeine in tea not so much. I don’t drink much coffee & when I do it’s decaf with real cream (lower carb).

Completely anecdotal, but I drink coffee like I need it to live and I’ve never noticed any change in my BG. There have been studies on caffeine in T2s that show some impaired insulin action, but I’ve never seen any data in T1 (might be out there, just haven’t seen it).

My younger Brother and I questioned this sugar rise many years ago. My Endo said it was our DP which was causing our sugars to rise not the coffee. Our DP normally occurs about 1/2 hour after we wake up.

We could both wake up with a Good FBS but soon after our sugars would start rising while eating or drinking nothing else. It Really peed my Brother off cause he couldn’t believe that he couldn’t even enjoy a black coffee without his sugars going up.

SO I take my Insulin right after I check my sugar to cut the DP down some. Then I have a few coffee(2% milk). A while later, I’ll have something for brekky. This helps to keep my sugars more stable.

I guess everyone’s mileage varies with caffeine. I bolus for coffee because the caffeine triggers my liver to release glucose (the caffeine is basically triggering my body’s fight or flight mechanism which I experience as “waking up.”)

I suspect that cutting down on junk food is more likely to help your highs than cutting out caffeine!

I never feel good when I drink Diet Coke. My blood glucose raises and I feel all cotton-mouthed and nauseated. I do, however, have to eat something when I have coffee. I like it black and it tends to give me lows if I drink too much.


I have to do the same thing with testing & injecting first thing in the morning.

My reaction to caffeine, even before diagnosis, wasn’t good. Makes me feel shaky, so I wonder if it triggers an adrenaline reaction that causes my BG to rise.

That could Very well be why you get the BG rise Gerri. I don’t know if you get DP or how yours works. Just because we all have Diabetes doesn’t mean that we are all wired the same. In fact, we are not. Don is right when he said, I guess everyone’s mileage varies with caffeine.

Not that it matters but when I drink a cup of coffee or tea, I only have half a cup of coffee(tea) and the other half is water(with milk), even when I order it at a Restaurant. Yes, I get funny looks.

But I’ve tested myself every which way. Different days I’d wake up with a Good FBG. I tried just drinking coffee, not drinking coffee, coffee with milk, coffee without milk, a yogurt, no yogurt, exercising, not exercising, just sitting there relaxing, sitting there watching tv, etc. No matter what I did, my sugars just started climbing each time as on cue.

Thus I agree with my Endo. It’s the DP. I call it delayed DP since as I mentioned, my sugar rise happens about a 1/2 hour after I wake up. So taking my Insulin right away works Good with or without coffee, to cut down the DP. I do not get shaky with coffee or without coffee unless I had a low, of course.

Great that taking Insulin right after you test works for your situation also Gerri.

Sorry, a yogurt, no yogurt was put in by mistake. That wasn’t part of the test.


Got a bad case of DP. Interesting about your delayed DP. I learn something new every day.