How long after a snack to measure blood sugar?

(BuckRimfire) #1

My spousal critter likes to have a mid-morning snack of tea and three “keto” oreo-type cookies. She wants to do an experiment where after fasting for about 33 hours to have a good baseline, she tests blood for sugar and ketones with my Keto-Mojo, then repeats the test after breaking her fast with those cookies. Then we’d repeat the test with some other foods of similar size on other days.

How long after eating do you guess would be best to catch the peak of blood sugar from such a small “meal?”

(I only rarely eat the “keto” carb-like products, myself, so I have little to say about them.)

(Michael - When reality fails to meet expectations, the problem is not reality.) #2

That’s the problem with manual blood tests. You’d learn a whole lot more with a CGM. You can use the glucose plot of day #1 to time your ketone blood tests on day #2 to try to catch ketone levels before, during and after glucose changes.

(Joey) #3

It depends in large part as to what you’re trying to better understand. Why begin after 33 hours? How does this make for a “baseline”? How would this be indicative of how her sweet cravings behave? How would a glucose comparison to other snacks inform her knowledge of how her cravings align?

Fwiw, I did a test on how stevia affected my glucose levels following ingestion. Might be of some interest in terms of the approach taken. (Below)

Let us know what you wind up doing and her results.

#4

Realistically every 15 mins for 2hrs, but if you guys are eating keto and doing it correctly than small blood sugar rises and ketone levels really make near no difference in your progress as a whole. Why care?

When the peak is and how long back to baseline is completely dependent on how insulin sensitive you are. Also, after almost 1.5 days of fasting that’s not a good baseline, you’d be way more insulin sensitive at that point and the curve wouldn’t resemble what it would normally when you’re eating.

(BuckRimfire) #5

We were listening to a podcast that mentioned CGMs yesterday and she said it would be interesting, but I doubt she’d actually be willing to wear one.

(Ian) #6

Having done many experiments like this, I too would highly recommend a CGM. Timing post postprandial spikes can be tricky depending on the nature of degree of refinement of any carbs you eat.

I think an 18 hour fast would be sufficient, from a last meal at around 6-7 pm, to achieve stable BG and long enough to get your "trouble and strife’ (wife) past the rise in BG caused by the dawn effect .

Testing every 15 minutes for 3-4 hours would give you good data (as a scientist, more data is always better), but involves a lot of blood letting. I personally found that 45 to 60 minutes after food consumption resulted in my highest BG levels. So you could test 30, 60, 120 and 240 minutes to give you an idea of what is happening and if you reach baseline within 4 hours.

(Joey) #7

@BuckRimfire I would suggest you and your spousal critter think through what actionable insight you’re aiming for?

You might be inclined to go about researching things quite differently depending on what you’re trying to accomplish.

Are there future decisions you’d be likely to change/adjust if you discover something? What would that something need to be?

I guess, you might consider establishing a “null hypothesis” before conducting your experiment so you can design it effectively. :nerd_face:

(Bacon is a many-splendoured thing) #8

My understanding is that the absolute values your wife will observe are not so important as the curve they represent. Insulin-resistance may or may not affect the curve. In other words, if your wife is slightly insulin-resistant, you may not see a difference, because serum glucose is responding properly, it’s just taking more insulin to achieve that response.

If it were possible to measure insulin at home, it would be the pattern of insulin secretion that would interest me, even more than the glucose readings.

But it should be possible to formulate some sort of prediction of what will happen. If the “keto” cookies contain very little carbohydrate and a great deal of protein and fat, I would expect a minimal effect on serum glucose. If the percentage of carbohydrate is fairly high in comparison to the protein and fat, then I’d expect a more significant effect on glucose.

(Bob M) #9

The common testing you see recommended is 1-2 hours after eating, but like Ian, I found that my blood sugar goes up and down way faster. Here’s Thanksgiving, 2017:

image
image.png1211×203 81.5 KB

Between each two lines is one hour. The 9.7 (=175 US) is from bread, stuffing, potatoes. The next bump to the right was dessert. You can see they go up and down in about an hour, so taking a test before I ate and afterwards would likely show little to no rise, and I’d miss the peak.

I’m not sure fasting would help, at least not 33 hours. As long as you don’t eat for some time beforehand, the test should be fine.

As for keto cookies, it would be interesting to see what happened. I’ve heard some say there’s a delayed effect, but I don’t know how you would test that. If you had higher (or lower?) blood sugar say 3 hours later, how would you know?