3

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Testing Postprandial Blood Glucose

Answered on September 12, 2014
Created August 05, 2010 at 5:15 PM

The typical directions for testing postprandial blood glucose just say to test after 1 or 2 hours after eating a meal. For someone who is mostly Paleo, however, I suspect that a typical meal may not contain enough carbohydrates for the postprandial test to be meaningful. If we want to do a postprandial blood glucose test, should we specifically ramp up on the carbohydrates during that meal? If so, how much?

Edit: By "meaningful" I meant using it as a diagnostic to test for diabetes or pre-diabetes.

3864f9a2af09b1b447c7963058650a34

(3703)

on August 06, 2010
at 05:13 AM

They do improve sensitivity however during chronic ketosis (or frequent IF), there is mild peripheral tissue insulin resistance which leads to 'slightly' higher fasting glucoses as mentioned earlier -- Will stated it right I believe -- just eating some carbs will fix the fasting glucoses. It's a feedback mechanism for the body to spare glucose since it is not readily available... usually it is not an issue (except the mildly high fasting). However I do believe ZC can worsen insulin resistance in those exhibiting adrenal or extreme hormone issues...

62ed65f3596aa2f62fa1d58a0c09f8c3

(20807)

on August 06, 2010
at 04:25 AM

Yeah, all the research I have read showed improved fasting blood glucose. Of course, all of that research was on diabetics.

34d2229c6bee7d4d99592031b6dbdd5d

(110)

on August 06, 2010
at 12:19 AM

i thought zero/low carb diets improved/increased insulin sensitivity?

7bea72ef073e8f76b5828727f1460900

(2718)

on August 05, 2010
at 06:31 PM

By "meaningful" I meant using it as a diagnostic to test for diabetes or pre-diabetes. Editing the question to clarify.

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8 Answers

4
62ed65f3596aa2f62fa1d58a0c09f8c3

(20807)

on August 06, 2010
at 04:43 AM

If you want to do a test that will closely mimic what the doctor does, you can use 28 jelly beans in place of the sugar syrup the doctor uses (link here: http://www.ncbi.nlm.nih.gov/pubmed/10561636 ). YOu do this in the morning after eating nothing since the night before. You take your blood glucose reading right before the test. Then you eat the jelly beans, then you start taking blood glucose readings (bgs) about once per hour or two for at least 5 hours, preferably longer. What you are looking for is to see how high your blood sugar spikes up and how fast it goes back down. You are also checking to see if the bgs go down too far many hours later. SOme people get hypoglycemia, aka too low blood sugars, long after they eat. So you want to check for that too and that means testing for a long time after the jelly beans. This will tell you what your response to carbohydrates is, ie how far up your blood goes goes and how fast it goes back down and how far down it goes. THis is what your doctor looks for. What he/she wants to know is how effective your body is at dealing with a sudden load of carbs.

Now another thing you may want to know is how your current diet is for keeping your blood glucose from NOT spiking up. Even if the bgs spike up on carbs, eating low carb can prevent spikes and the damage spikes cause to your body. If you already have good response in the glucose challenge with the jelly beans, then you are probably fine, but it's nice to know what happens when you eat your food. It's also sometimes interesting which foods do and do not spike glucose levels. So in that case, you just eat your normal food, or maybe one of your more carby meals, and then see how good or bad your blood glucose numbers are afterward. This will let you know how well you are handling your current types of food intake. People argue about how strict you should be on judging bgs and if they are good or not, but many feel it is good if your bgs do not come up more than at about 120 or 130 and then are back down to normal within 2 or 3 hours. It is also preferred if your fasting blood glucose (bg a long time after you have eaten) is below 100 but preferably more like 80 or 90. Personally, I think close to 80 or 85 is a good number. I saw research once that people with 80 or 85 as the resting bg were much less likely to later develop diabeties than people with higher resting bgs.

Also keep in mind that stress and illness can cause bg numbers to be temporarily elevated. So to get a good idea, you may need to take several readings over different days and do not bother to do it if you don't feel really healthy that day. (unless of course you suspect hypoglycemia and what to check for that) -Eva

2
58a49b7e6356bd3eaaefed676445b720

on August 05, 2010
at 06:21 PM

What would be the point of testing for a meal that you'd never eat otherwise? It doesn't make sense to me to up the carbs just for the sake of a test. However, if you're curious about how a certain "borderline" food (like sweet potatoes, e.g.) might affect your blood glucose, then doing a test on that particular food makes sense.

1
F1e5ff10797e0e35cda081a4221cb614

on August 28, 2010
at 03:30 PM

All you need is an inexpensive glucose meter. I'd suggest ingesting around 85 g of foods rich in high glycemic carbohydrates; e.g., 2 to 3 medium-sized white potatoes baked and without skin. Eat these by themselves, with no other foods.

The following are indications of abnormally elevated glucose and insulin responses, respectively: an abnormally high glucose level 1 hour after a meal (postprandial hyperglycemia); and an abnormally low glucose level 2 to 4 hours after a meal (reactive hypoglycemia).

What is abnormally high or low? Take a look at the peaks and troughs shown on the graph in the post below; they should give you an idea.

http://healthcorrelator.blogspot.com/2010/05/blood-glucose-variations-in-normal.html

1
3864f9a2af09b1b447c7963058650a34

(3703)

on August 05, 2010
at 08:38 PM

I would concur w/Will -- naturally insulin resistance occurs mildly with low carb or ZC (zero carb) and the fasting glucoses will be higher as a result, even putting some people clinically in the 'prediabetic' camp.

Postprandial glucoses are meaningful if you are trying to find signficance related to organ function and trying to prevent damage from glycoslylation, AGEs and other high glucose related cellular damage -- higher glucoses can be good surrogates to indicate insulin, cortisol, thyroid and/or progest/testosterone imbalances. Low vitamin D and high omega-6/low omega-3 can also predispose people to elevated glucoses.

34d2229c6bee7d4d99592031b6dbdd5d

(110)

on August 06, 2010
at 12:19 AM

i thought zero/low carb diets improved/increased insulin sensitivity?

62ed65f3596aa2f62fa1d58a0c09f8c3

(20807)

on August 06, 2010
at 04:25 AM

Yeah, all the research I have read showed improved fasting blood glucose. Of course, all of that research was on diabetics.

3864f9a2af09b1b447c7963058650a34

(3703)

on August 06, 2010
at 05:13 AM

They do improve sensitivity however during chronic ketosis (or frequent IF), there is mild peripheral tissue insulin resistance which leads to 'slightly' higher fasting glucoses as mentioned earlier -- Will stated it right I believe -- just eating some carbs will fix the fasting glucoses. It's a feedback mechanism for the body to spare glucose since it is not readily available... usually it is not an issue (except the mildly high fasting). However I do believe ZC can worsen insulin resistance in those exhibiting adrenal or extreme hormone issues...

1
F8fa4b0809d3b74fcf0361c0d53b60c1

(911)

on August 05, 2010
at 06:46 PM

What you are looking to perform is an oral glucose tolerance test.

Since you are doing this at home, you won't have a glucose solution. Ideally use a boiled root vegetable, or rice, to get you to around 75 g carbohydrates.

Due to physiological insulin resistance induced by high circulating free fatty acids, you will need to eat carbohydrates for a period of time before the test. According to Peter: "The general opinion in LC circles is that you need 150g of carbohydrate per day for three days before an oral glucose tolerance test."

0
5de2fffda92c0bf2be7ede10cad55546

(1781)

on August 29, 2010
at 01:26 PM

Why do you think you are diabetic or pre-diabetic? If in fact you were pre-diabetic going paleo for any length of time should have righted that. Any other test you do will be fairly meaningless, and I can't imagine why you would want to ingest glucose or sugar or jellybeans or any of that rubbish, you'll likely make yourself sick. If it's just curiosity I'd say deal with it, there are more important things to worry about.

0
34d2229c6bee7d4d99592031b6dbdd5d

(110)

on August 05, 2010
at 06:25 PM

What do you mean by "meaningful"? What are you testing our blood glucose to see?

7bea72ef073e8f76b5828727f1460900

(2718)

on August 05, 2010
at 06:31 PM

By "meaningful" I meant using it as a diagnostic to test for diabetes or pre-diabetes. Editing the question to clarify.

-1
Da397846a2cfad231a1122126bb6eda7

(227)

on August 05, 2010
at 10:26 PM

If you're asking how you can do a DIY glucose tolerance test, go here:

http://www.phlaunt.com/diabetes/spindex.php

Explore the site, it has loads of additional info about blood glucose and diabetes/prediabetes.

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