Fasting Blood Sugar Highs/Lows and Somogyi Effect


(Joanne) #1

Hi all, I am truly stumped about my fasting blood sugar. I went off the rails last night and had a rare binge (crackers, cookies, chips and a couple glasses of wine) and I was shocked to find my am fasting glucose this morning was lower than it’s been in weeks…95. Usually it’s in the 105-115 range when I stay on plan with healthy keto and fasting the day before. Any ideas why this happened?

I have read about the Somogyi Effect—that sometimes the liver pumps out glucose if your blood sugar drops too low during the night. Could this be the reason I usually have high FBS? Too low BS in the middle of the night from keto + IF? If so, the standard recommendation is to eat something carby before bed—an apple with cheese or crackers with peanut butter. I’d rather not do that as it would break my fast and take me out of ketosis.

For background. I have T2D that has been controlled/reversed with keto + IF. I also take metformin with my midday meal.


(Jane) #2

I can’t answer your other questions, but just wanted to add that I have experienced this myself. I was doing a 4-day fast a couple of years ago and my BG dropped to 63 (ketones were 6.6 so I felt fine). My next BG was over 100 and all I had was water to drink, so my liver definitely decided I needed more glucose in my veins and I had not ingested any calories to raise my BG.


(Bob M) #3

I believe it’s a case where your body realizes it doesn’t have to increase blood glucose in the morning/make you insulin resistant, so it doesn’t. My morning blood sugar is around 100 every morning when I’m eating keto, but I’m sure drops lower if I eat higher carb.

In fact, I’ve seen people who advocate eating small amounts of carbs at night to lessen the morning effect on blood glucose.


(Joanne) #4

Yes, that’s what I’ve seen recommended. But I don’t know if it’s worth breaking a fast (and ketosis) to get a 10-15 pt lower FBS…cost/benefit. Maybe a protein snack at night would be a better option? I plan to experiment and see.


(Old Baconian) #5

Now, see, for myself, I’d be more concerned with the insulin response that lowered the glucose from those carbohydrates, than I would be with the actual glucose level. But since measuring insulin is impossible at home, I guess we tend to think, “out of sight, out of mind.”

(sigh) I guess we’re not likely to see a home insulin test anytime soon, unless someone can come up with a test that doesn’t require a radioassay. . . . :frowning_face: