Unexplained spikes before lunch

Hi! I am a T2, dx about 10 years ago, and have developed an intolerance for Metformin. Therefore, I started Lantus several days ago. Numbers are very slowly dropping while I figure out the dosing. What is odd is that I have noticed that I will take a “post breakfast” reading, eat nothing, drink only water, and when I take my “pre lunch” reading my BG will have jumped about 50 points. This has never happened before. It may just be stress. Is it common for someone’s BG to jump in the daytime without having eaten any carbs?


Mark - I’m not T2, so I can’t comment from my experience. What I do know is that even people without diabetes can experience a climb or fall of 50 mg/dl within a normal blood sugar range.

There are other factors that can drive blood sugar like liver glucose output variations and other counter-regulatory hormones like glucagon and cortisol. It’ not simply an isulin/glucose dance.

And I’m sure you’re aware of the effects of exercise on blood glucose. Some high intensity exercise, like weight-lifting, can drive blood glucose up.

It’s wise to keep actively monitoring your blood glucose levels as you become more familiar with your metabolism.

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Many people experience greater resistance to insulin in the morning, so a morning BG rise, absent any food effect, can still explain this phenomena. There’s another recent TuD thread that explores the effects of skipping breakfast on T2 blood glucose control. It was very active and may provide some insight into your experience.

As a T2 I have a wicked case of Dawn Phenomenon (I call it Darn Phenomenon). I actually bolus rapid insulin upon waking in order to compensate. Basically your body clears out insulin overnight and then releases stress hormones in the morning to get you up and moving. All this conspires raise your blood sugar and make you insulin resistant. You may not have noticed this if you didn’t do a lot of testing in the morning before starting Lantus.

I have always noticed a rise from bedtime reading to AM fasting reading, but never a significant rise from “post breakfast” reading to “pre-lunch” reading. Just seemed really odd after all this time. Dunno.

I’m Type 2 on insulin. I definitely have experienced similar “unexplained” spikes on mornings when I skip breakfast. I use a Dexcom CGM, so I can notice those trends and can take small correction doses of fast-acting insulin before they get out of hand, but the longer I wait to first eat any morning, the higher my BG rises. Call it Dawn Phenomenon, or simply the liver reacting to the “starvation” by releasing glycogen, the result is the same: a rise in BG that could be quite significant.

If you’re able, you could try taking a short walk or some other kind of activity during that time. It might compensate for the difference.