Post meal BG readings - how important are they?

[birchy66]

I was diagnosed Type 1 in March 2013. My diabetic nurses at hospital gave me a BG range of 5 - 9 mmol and advised me to monitor pre-meal BG readings only. Most of the time I am within the target range but occasionally have higher readings pre-bedtime (getting better though) and the odd low during the day if I am very active (I was 3.6 pre-evening meal today!) . Took a swig of Lucozade and OK within a few mins.
I have read that post-meal readings are important but my DN said I could check now and then if I was worried. I had assumed that if I get my HbA1c within 6.5 to 7.5 I will be doing OK (7.6 in June). My question is should I be checking my post meal BG or not? :crazy:

 

[lindisfel]

I was diagnosed Type 1 in March 2013. My diabetic nurses at hospital gave me a BG range of 5 - 9 mmol and advised me to monitor pre-meal BG readings only. Most of the time I am within the target range but occasionally have higher readings pre-bedtime (getting better though) and the odd low during the day if I am very active (I was 3.6 pre-evening meal today!) . Took a swig of Lucozade and OK within a few mins.
I have read that post-meal readings are important but my DN said I could check now and then if I was worried. I had assumed that if I get my HbA1c within 6.5 to 7.5 I will be doing OK (7.6 in June). My question is should I be checking my post meal BG or not? :crazy:

Hi Birchy,
I am Type 2.
If you use your meter say at 1 or 2 hours after your initial intake of food you will see what is 'spiking' your blood glucose and then you can eat differently to reduce the spike on your meter.

It is usually bread and potatoes that spike me so I have reduced my intake and I'm trying to eat low GI.
atb
Derek

 

[SamJB]

Hi birchy, this should have been posted in the Diabetic Nonsense thread! I can't believe a DSN would say this. The aim for all diabetics is to have good sugar levels all the time. What makes before meal readings so special? Bizarre.

Maybe it's because you are new and she doesn't want to give you insurmountable targets, but you should aim for 4-9 after meals and 4-7 before meals.

 

[noblehead]

My question is should I be checking my post meal BG or not? :crazy:

Yes indeed, it's only by bg testing that we can control our diabetes, until times change we have no alternative but to test.

 

[ElyDave]

I'm checking both pre and post meal and recently had seen a few post meal readings drifting above my target of 4-8. When I discussed this with my excellent DN/dietician, she told me that evidence suggests that the post meal reading (i.e. 2hr) is not so important overall as long as the reading returns to normal before the next meal

 

[SamJB]

Unfortunately, Dave, she is completely incorrect. For example, I managed to knock 0.5% off my Hba1c by switching to low GI foods. I discovered I was getting a 1 hour spike after eating and by 2 hours later my levels were fine.

I work modelling the exposure of oncology drugs to tumours in the human body, the same principles of exposure are applied to glucose and insulin in diabetes research. Absolutely any exposure of elevated sugar levels will adversely affect a patient's HbA1c, because it increases the exposure of red blood cells to glucose. Therefore, any organ in the body will be exposed to elevated glucose levels, increasing the risk of complications. No matter what a DSN says, that is an inescapable fact.

 

[ElyDave]

Unfortunately, Dave, she is completely incorrect. For example, I managed to knock 0.5% off my Hba1c by switching to low GI foods. I discovered I was getting a 1 hour spike after eating and by 2 hours later my levels were fine.

I work modelling the exposure of oncology drugs to tumours in the human body, the same principles of exposure are applied to glucose and insulin in diabetes research. Absolutely any exposure of elevated sugar levels will adversely affect a patient's HbA1c, because it increases the exposure of red blood cells to glucose. Therefore, any organ in the body will be exposed to elevated glucose levels, increasing the risk of complications. No matter what a DSN says, that is an inescapable fact.

That would have been my logical thought process too as a chemical engineer with some knowledge of biological processes. I don't go for low carb - I think that would be unfeasible with my level of athletic activity; but like you go for low GI where possible, so yesterday was a bowl of spicy lentils and veg for example. I limit bread to normally one slice per day and that is wholemeal, preferably sourdough rye etc etc.

The reason I asked her was that I'd seen post meal readings start to drift up a bit, now going back down again. My last HbA1c was pretty good though at 46. To be honest my overall diet has not really needed to change since diagnosis, just generally dropping the few desserts that I used to have, now typically one per week.

The biggest problem I've had with low GI is getting the dose timing right, as I've had post meal lows as the insulin acts ahead of the carbs release.

 

[drumming_blitz]

I My question is should I be checking my post meal BG or not? :crazy:

Doing DAFNE and on Humalog I was told that unless i'm ill I shouldn't check my sugar levels between meals, as it takes up to 5 hours for my insulin to finish working completely. Now looking at your insulin, it looks like it has the same duration period. BUt you can check it out here:

http://diabetes.niddk.nih.gov/dm/pubs/m ... ert_C.aspx

Now the reason why I was told not to is because it will be too tempting to correct if you see that your sugars are still high and potentially cause a hypo.

So, if you resist the temptaion to do more insulin, then feel free to test post meal.

 

[Sarah69]

When I was on insulin I was asked by my DSN to only test before meals. I also was never told I could do correction doses, I knew you could be reading these forums? Now I'm on Byetta I was told I don't need to test many times at all but I still do the 4 a day?

 

[SamJB]

The 2 hour post-meal BG test tells you whether your meal-time insulin dose was correct. So if you don't take a 2 hour post-meal reading, how do you know whether your insulin dose was correct? The answer is, you don't. If your basal dose is incorrect, then pre-meal readings are going to be influenced by your basal insulin as well as your fast acting. Then how do you figure out if your fast acting dose was correct? The answer is, you can't. If your basal is correct, then how do you know whether the food you are eating is not causing your levels to spike? The answer is, you don't know. Also, don't expect your insulin:carb ratio to be static either long term or throughout the day. If you don't take a 2 hour post-meal reading, how do you know it's consistent? The answer is, again, that you don't.

Therefore, the 2 hour post meal reading is essential if you want to maintain good control. It irritates me that health care professionals - supposed "specialists" - are saying that you don't need to do a 2 hour post-meal reading. Sure, if your basal level is perfect and unchanging, your insulin:carb ratio is perfect and unchanging, you don't suffer spikes, you eat the same thing every day and your levels are persistently perfect after eating, then you probably don't need to do the 2 hour test. But how many of us out there are like that? Not very many, I imagine.

Correction doses between meals (i.e. > 2 hours after eating) are fine so long as you don't stack a load of correction doses on top of each other. If you do stack a load of correction doses together, chances are you'll end up hypo. The 2 hour reading should be roughly consistent with the pre-meal reading. Insulin profiles have been designed to roughly match the glucose profile from ingested food. So you should aim for the pre-meal, post-meal and 5 hour after meal readings to be roughly the same.

Personally, my levels are very stable and so I know if my levels are > 7 mmol/l 2 hours after eating, I'll give myself a correction dose and I won't end up hypo. I wouldn't advocate correction doses when you are in single figures, unless you have stable levels and are confident that it won't result in a hypo. But, if you are say (this is a subjective figure) above 12 mmol/l more than 2 hours after eating then I think a correction dose is required and you probably need to have a think about why you ended up at 12 mmol/l.

 

[ElyDave]

Absolutely Sam

in the last week I've had
1 hypo - dosage right, but timing wrong - slow release porridge
2 hypers - >8mmol/l for me

Both case were due to rice, which I'm still having trouble estimating. First time up to 11.3, but could also have been a pint of frothy brown ale which I didn't account for. It was still >11 3 hours after the meal, so I corrected with one unit of rapid acting at bedtime
Second case, rice again, but this time only to 9.4, so obviously I'd learnt.

Mostly I'm in range, well over 90% of the time. I intend to still be here with everything attached and working in 30 years.

 

[SamJB]

I intend to still be here with everything attached and working in 30 years.

I agree, Dave. In my experience extra diligence pays well and if it means I'm still here with everything attached in 30 years, then it's diligence well spent, in my opinion.