When does the two hours start?

If I tested 2 hours after finishing a meal I would have much better results than I do by timing my testing from the start of a meal and would very definitely not catch any peaks. My peaks are almost always at 90 minutes from start of a meal, no matter what I eat, and are on their way back down at 2 hours after starting to eat. I prefer to know my peaks and how long after them that I am back to normal.

azure said:

The two hours is from the start of your meal unless there are special circumstances @Harebrain @oopsie

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Oh dear, I've been doing it wrong then after all these years, I've been testing 2 hours starting when I finish my meal.

carina62 said:

Oh dear, I've been doing it wrong then after all these years, I've been testing 2 hours starting when I finish my meal.

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I don't think it's that critical. For me as I don't produce saliva hardly at all the digestive enzymes present in saliva are not there so for me the digestion of carbs starts when the the food leaves the stomach and enterers the intestines so I always add about a half hour on. Seems to work for me.

2 hrs is an approximation of when a meal has the greatest affect on your BG level, each meal varies in it's post prandial peak so 2 hrs after you start eating or 2 hrs after you've finished eating doesn't make that much difference in the grand scheme of things, consistence is probably more crucial, unless you're eating for hours at a roman banquet(!) - if you are concerned about it there's nothing stopping you doing a sequence of 15mins tests to satisfy your curiosity (apart from the cost of strips and bleeding fingers!)

Harebrain said:

This may seem a silly question and has probably already been answered. Having just done my post breakfast BG it has prompted me to ask. Talk is of testing two hours after eating. However when does the two hours start?

Some meals take longer than others so when should I start the time?

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i am T2 on LCHF without meds. For what it is worth, I start my 2 hours at the end of the meal. I am usually too busy shovelling food into my gob to remember to set my timer after the first bite. I take bitter gourd tea after each course, and I set my timer a after the last course . This means, at home, when dinner is one course, i figure 2:00 hours or 2:20 hours, am I going to die? No, then move on. At, say, a wedding where the meal is spread over a few hours, I start the timer after a taste of the dessert. I reason here that it is too much of a mind snap to work it out here, so I take the easy way. As my A1c is usually around 6.1, I can't be that wrong.

oopsie said:

View attachment 20091I'm only 2 weeks diagnosed, the quote is from this site (other sites say different times) It doesn't say at 1st bite, if you mean at 1st bite then the page should be updated. (still on the learning curve)

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Grab yourself a Freestyle Libre.

Accuracy fine for some people, awful for others - myself included.

I still found it invaluable as an education tool when I was diagnosed earlier this year.

The idea is to read your blood sugar at the 2 hour point as an indicator of how well your body is dealing with what you've just eaten. BUT if the meal has had a lot of fat then it slows the absorption of glucose and the peak will have been later. Libre showed me that I had four low peaks over as many hours. It explained why the 2 hour blood test was LOWER than my pre-pizza BG, as it happened to be in a trough!

Just make sure that you do BG before you respond to any low/high readings from Libre. I'd only had mine of for a few days when I got a LO reading, and not knowing what a hypo feels like (still don't!) went and ate honey. Turns out, as I said, that it's totally inaccurate for some peeps, and LO on it corresponds to 4.8 BG for me

Good luck with the (rather steep!) learning curve

Niki

Once that first mouthful of food is swallowed - that's the start of timing for 2 hours for me .

azure said:

Yes, many sentences like that, here and elsewhere, are confusing. It confused me when I was first diagnosed so I checked with my consultant and DSN too.

It's two hours after the start of the meal as the "first bite" starts a chain of metabolic events.

You can test at other times too eg after one hour (one hour after the start of the meal) and also continue to test at three hours, etc, to see what your blood sugar is doing, but the commonly read "test two hours after eating" refers to testing two hours after the first bite

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Your explanation "...starts a chain of metabolic events" is really helpful - I always need to understand 'why' - although I still don't quite understand why it's from the beginning of a meal, when those metabolic events are surely continuing throughout a meal?

I've struggled with the logic of the 2hours as our evening meals tend to be quite long affairs... I tend to zap the "pudding" down while others are still munching their mains... tend to test at 18:58, listen to the Archers while finishing off prep, serve at 19:15 to 19:25 and finish eating round 20:10 and test 21:15 to 21:30... after +600 evening tests the numbers are pretty constant..

AnnKelcey said:

Your explanation "...starts a chain of metabolic events" is really helpful - I always need to understand 'why' - although I still don't quite understand why it's from the beginning of a meal, when those metabolic events are surely continuing throughout a meal?

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I'm no scientist or medic so I apologise for the non-technical explanation : D

The Two Hour Post Prandial Test is a recognised medical test with clear guidelines, one of which is the 'timer' starting from the first bite. It's to compare a person's response with a normal response. There are desired outcomes from that first bite, and that is how it is measured for consistency.

Yes, digestion and metabolising continues during the meal and after, but this Two Hour test is simply looking at the response after 'first bite' as that first bite is the starting point and two hours is the end point for this test.

You can add in extra tests both before and after, but the two hour result is two hours from the start of the meal.

Sometimes I do extra tests to get extra information, and I think that's quite common (and useful) but consistency is important when you're comparing 'two,hour tests' or discussing them with others. Two hours after first bite isn't a magic formula - just a standardised way of testing

If I've understood this thread the timing is from the start of the meal, and it's not overly critical, one could read after two hours and half the start of meal because the peaks depends anyway on what one had eaten, but it's useful to mantain consistency.

If a meal is two hours long, say because one is in a restaurant with long serving times and/or is a special occasion, one has to test exactly at the end. If the cake has still to arrive because the newlyled are busy making photos one has the added bonus to know if eat the cake or politely and quetly leave on the dish

Testing 2 hrs after the start of a meal makes no sense to me. Surely the idea is to find out the impact food had on bs which can only be tested after it's been digested? If the test is carried out before this, then the result is being taken while food continues to be digested and does not reflect a true 'spike'.... Ie food can continue 'spiking' after the test??

Lifeissweetenough said:

Testing 2 hrs after the start of a meal makes no sense to me. Surely the idea is to find out the impact food had on bs which can only be tested after it's been digested? If the test is carried out before this, then the result is being taken while food continues to be digested and does not reflect a true 'spike'.... Ie food can continue 'spiking' after the test??

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You can continue to test after and map what your blood sugar does

Two hours after the start of the meal is the time a non-diabetic person's blood sugar should be back in range. It doesnt mean you can't test earlier or later, but the instruction to test two hours after your meal refers to two hours after the start of your meal.

Food affects your blood sugar before it's been digested. This two hour test is a specific medical test and that's what it means - two hours after the start of the meal.

This thread seems to have served its purpose now so I am locking it The OP's question has been answered