Big BG Rise for No Apparent Reason

(Dee In NY, US wasT2D. Started keto June 14, 2019) #1

My BG went from 101 / 5.6 to 130 / 7.2 in 90 mins this morning after eating 100 gr of plain yogurt. Even if the carb count (3) is wrong, that doesn’t explain such a drastic rise. I checked 3 times on my keto mojo and got similar readings, then with my Contour Next glucose monitor and got the high reading there too.

I washed my hands well between each test, just in case I had something on them, and I even changed the needle in the lancet.

My ketones were 3.3, so my GKI is still in the good range at 2.2, but wouldn’t the high BG trigger an insulin release? I certainly do NOT need that, as IR as I am.

I took supplements at the same time as the yogurt, but they are the same ones I take every day. This has never happened after taking the supplements, so it has to be the yogurt.

I believe that if you have none of your own insulin, 1 g of sugar can raise your BG 5 points. If so, then 3 g should only be able to increase BG by 15 points.

I’m baffled! Any thoughts? In any case, no more yogurt for me.

(Bob M) #2

You blood glucose started where and went to where?

(Dee In NY, US wasT2D. Started keto June 14, 2019) #3

Yeah, it would be helpful to add that information, wouldn’t it?. I’ve added it now.

(Bob M) #4

That does seem like a lot. Have you measured every morning? That is, what happens if you don’t eat breakfast or what happens if you do?

The reason I ask:

You can see my blood sugar goes up every morning…no matter what I do (though I usually don’t eat breakfast).

Mine’s only about a 10 point or so rise, but throw in some testing error and maybe higher values for you, and this might help explain it.


What did you eat yesterday? I see spikes in my patient in fasting glucoses or after they eat, sometimes in response to an earlier meal & not the immediate previous one. (For example might see the a spike mid day after a salad but it’s really from the muffin in the morning). It’s also possible that the yogurt had up to 12 grams of carbs, or that your body is reacting to the lactose.

(Dee In NY, US wasT2D. Started keto June 14, 2019) #6

I looked back over my food log and I’ve had yogurt several times (including yesterday), but didn’t check my blood sugar for 4 to 12 hours after, so I don’t have any data for it.

@Erevehc yesterday I ended my fast of 72 hours with pork ribs, then later on chaffle pizza, then later cheeseburger, then after that more pork ribs. I did have yogurt in there as well, but didn’t check my BG until 5.5 hours afterward and it was 94 / 5.2 which was actually high, since the previous reading yesterday was 79 / 4.4.

It’s very startling to eat 100 g of yogurt that is supposed to be very low carb and get that much of a reaction. For now I guess it’s no more yogurt for me. I do have cream fermented with viili culture, but I don’t love the taste.

(Bob M) #7

I wouldn’t stop eating yogurt if you like it. Just test to see what happens. And note that sometimes you might not get the same response. Maybe this was just a fluke?

(Dee In NY, US wasT2D. Started keto June 14, 2019) #8

I’ll lay off for a few days, then add it back in and see what happens. And perhaps it makes a difference as to whether or not it’s the only thing in my stomach.


Yea so that’s a little less than half cup. Is this Greek style or regular whole milk yogurt? I do Greek style in similar quantities without an easy but I know everyone is different. A 30 point spike after eating isnt too much to me, but I know you’re still working on decreasing your fasting sugars

(Dee In NY, US wasT2D. Started keto June 14, 2019) #10

It’s Greek style.

Just checked my blood again (4 hrs after the yogurt) and it’s much better: 108 / 6.0. Whew!

(Bob M) #11

You might also change when you take blood. Maybe take it every 15 minutes or 30 minutes for something you think will raise your blood sugar. I say this because you took it 90 minutes after eating. Here are my results from Christmas day, 2017:

Where the 5.9 is, that was probably before our “lunch”, then a break, then dessert of 8.5 (153). The spacing between each two lines is only an hour, though. Were I to take my blood sugar before I ate then about an hour later, I’d completely miss the peak and I’d be back to normal.

This is of course my response, which seems unusual, as most places recommend taking blood sugar 1-2 hours later:

However, I have a lot of data showing spikes that start and finish within one hour (except pizza, which causes a high blood sugar for a while).