I know that being in ketosis means that our morning blood sugar will be higher, due to the dawn effect. Here is my data for about a month last year at the end of the year. This is taken from a FreeStyle Libre continuous glucose monitor:
This is two weeks in July of this year:
You can see the pattern: my blood sugar is lowest around midnight or so, then goes up all day until around noon, then goes down all day. 90+ percent of the time, I do not eat breakfast. I have coffee for breakfast, typically with a small amount of cream. If I’m eating, I eat anywhere from 10 am (after a workout at 6-7 am) or maybe 11 am. I currently drink green tea after my coffee, but did not last year. If I fast more than 24 hours, the same pattern emerges, except that everything is shifted downward.
This gives you more detail about what this really looks like. Note that this has the Christmas holiday in it, so I’m sure I partook of high sugar sweets, mashed potatoes, etc. The red means I went below 3.9 (70.2), which isn’t unusual, especially if I’m fasting. That really low red line around 14:00 is probably because I think a sensor came off.
Why does my body want me to have higher blood sugar in the morning, but apparently not care about me at night? Why do I “need” higher blood sugar?
And note that my ketones are all over the place; I could have ketones of 0.0 to 1.0+ (usually have very low ketones, below 1) while my morning blood sugar is the same. I could eat late the night before or not eat late and my blood sugar will be about the same. The only time my morning blood sugar comes down is if I fast for multiple days.
This also creates a problem for testing. I’ve tried to test whether coffee (with/without cream) causes my blood sugar to go up, and test whether a drink of alcohol causes my blood sugar to go down, but since I drink coffee in the morning and my blood sugar goes up anyway, and I drink alcohol at night when my blood sugar goes down anyway, it makes it difficult to see a pattern. Before I had the FreeStyle Libre, I was convinced coffee caused my blood sugar to go up, so I tested every half hour or so (using a pin-prick meter) after having coffee… my blood sugar went up! That proves it! Then I delayed drinking coffee until later times in the morning…and my blood sugar went up. And it would either not change or go down after my delayed coffee.
I have been on low carb about 5 years. I’m still “obese” technically by BMI but am down around 50 or so pounds. It’s hard to tell, as I had shoulder surgery and lost a ton of muscle mass that I’ve been slowly getting back.