Taking Blood Glucose one hour or two hours?

Carole12 said:

I’m prediabetic (HbA1c reading of 47) since 25th April. I’ve gone all out on daily carbs of between 50 to 70g, no sugar, cut down on fats. I’ve lost 2.5kg and am already getting really good blood glucose readings before and after meals after 2.5 weeks.

My question is:

I seem to be getting a PEAK reading with my blood glucose meter after one hour and a much lower one after two hours. I’ve been told that I must take it two hours after a meal, and not one hour, but this would make my reading alot lower if I were to do this.

I was also told that a non diabetic peaks at one hour and after two hours the reading goes down.

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Hi, and welcome to the forum.

it does seem you have found your spike. And well done on your two hours results and your weight loss.
I spike around forty five minutes, others will spike around the hour mark, but some later, some sooner. It all depends on the individual, what you eat, how your diabetes occured, and if you have insulin resistance or your hormonal (insulin) response to food. And the carbs you eat.
That is the reason why it is recommended to test pre meal and two hours later. The proviso being that, your two hours result is within two mmols of your pre meal reading.
But this is just a guideline, it is again what the individual is trying to find. Wether experimenting or discovery of certain foods or drinks. It is a good guideline of baseline, to see trends. And I would recommend keeping a food diary. This will help not only you, but your doctors as well! It will help them to see how intolerant to carbs you are.
Keep testing, keep safe.

Carole12 said:

I’m prediabetic (HbA1c reading of 47) since 25th April. I’ve gone all out on daily carbs of between 50 to 70g, no sugar, cut down on fats. I’ve lost 2.5kg and am already getting really good blood glucose readings before and after meals after 2.5 weeks.

My question is:

I seem to be getting a PEAK reading with my blood glucose meter after one hour and a much lower one after two hours. I’ve been told that I must take it two hours after a meal, and not one hour, but this would make my reading alot lower if I were to do this.

I was also told that a non diabetic peaks at one hour and after two hours the reading goes down.

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The test is to see how you are dealing with the meal - it isn't to see what the numbers are so much as what difference the meal has made and how you cope with the foods.
When you see the after meal number at two hours from starting to eat you can usually gauge how things are going for you and if you need to adjust the amount of various foods you are eating.
When I was sorting out my diet I could see that peas and beans were not a good choice for me as I was seeing higher numbers than I should have. I seem to be able to extract more carbs from legumes than are listed - about 180 percent of the amount. These days I eat a half portion - though it is strange as they are quite sweet tasting now I am not having anything with sugar or sweetener.

Resurgam said:

The test is to see how you are dealing with the meal - it isn't to see what the numbers are so much as what difference the meal has made and how you cope with the foods.
When you see the after meal number at two hours from starting to eat you can usually gauge how things are going for you and if you need to adjust the amount of various foods you are eating.
When I was sorting out my diet I could see that peas and beans were not a good choice for me as I was seeing higher numbers than I should have. I seem to be able to extract more carbs from legumes than are listed - about 180 percent of the amount. These days I eat a half portion - though it is strange as they are quite sweet tasting now I am not having anything with sugar or sweetener.

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Could it be the protein in the legumes causing a difference rather than carbs? I understand that carbs have the biggest (and quickest) influence on BSL and that’s what most people correctly focus on, but protein raises my BSL, it just takes longer. E.g. my protein shake before bed — when my bolus insulin has worn off so that shouldn’t be affecting my experiments — raises my BSL by about 2 mmol/L and it stays raised for hours. There’s basically no carbs in my shake because I use almond milk. I’ve also done the experiment by eating just the dry protein powder (I don’t advise this because it’s not a pleasant eating experience, but I wanted to eliminate as much as I could to concentrate on the protein effects) with the same result so I’m fairly confident that the peak I see is from protein. Also legumes generally have a good amount of fibre in them which can delay the peak and push it out to the, example, three hour mark. Before my CGM I was testing 1 and 2 hours post-meal and still missing my peak because I’d probably call my diet high fibre, high protein, low carb. Everyone’s different of course, I just thought I’d share my experience

As I understand it, the 2 hour post meal test is to check how well we've dealt with the carbs in that meal - by seeing how close our glucose has come down again to our pre meal test level.

The level at one hour may be part of a high sharp spike or more of a longer/slower smaller bump, depending on the amount and combination of carbs & fats in that meal, and you may possibly miss the timing of the actual highest point.

When (or how) you test really depends on what you want to find out, but in general the recommendation is to test pre immediately and 2 hours later. Using a continuous glucose monitor such as the Libre is a much more useful tool for discovering what's going on while eating.

(My glucose meter allows me to to set myself target ranges to keep within and I find this more useful rather that worrying too much over individual numbers. But I found wearing Libre sensors for a time definitely gave me a much better idea of what was going on overall.)

plantae said:

protein raises my BSL, it just takes longer

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Protein seems to affect my BSL too. Since going low-carb (<45 per day) I found that my insulin to carb ratio changed. When eating more carbs my ratio was 1 unit insulin to 10 carbs; now that I'm low-carb, it's 1 unit insulin to 5 carbs, and I think that's because of the protein. Dr Bernstein, a pioneer in the wisdom of cutting carbs for Type 1s, says that if you follow low-carb, the protein eaten needs insulin coverage. My basal is fine, so long as I don't eat more than 10 carbs at my 6:00pm meal and afterwards, my BSL stays pretty much the same 'til morning. I wake up alot from nightmares and I check my BSL then. I don't do any calculating for the protein I eat, I just experimented by changing my ratio a unit at a time until I reached this 1:5 ratio that is working well for me. The reason I low-carb is because the spikes and crashes were driving me mad.