As has been said above regarding carbs, fats etc.....personally i wouldn't read too much in to this whole "don't spike more than 2 mol/mmol" stuff - i know it's been stated in some report somewhere (can't recall where now) but its generally rubbish as most non-diabetics and diabetics with good control will spike more than that ordinarily, depending on carb./sugar intake and without overtly affecting their HbA1c when tested. In fact there are reports of study groups of individuals tested whom have definitively not got any kind of endocrine disorder whatsoever, and yet post-prandial spikes were observed of up to 9.3 mol/mmol.
Edit to add... TL;DR - a spike in BG will impact your hba1c. How many and how high is entirely up to you, your BGM may help
That’s a very interesting response. Please take the time to link the studies or accompanying data so that we may review?
From my own data of BG testing I can categorically say that keeping to a rule of ‘no more than 2.0 rise’ has worked wonders.
When I have my hba1c test a week on Friday, I will publish the results, along with the MySugr app which has been recording everything.
I’m on holiday at the moment, and trying a few different things, and where I have had a low number unfortunate spikes of 3+, they do impact the overall predicted hba1c. Of course they do, if you go 4, 4, 5, 4, 5, 5, 6, 5 regularly (FBG, 3 meals, final BG) and start throwing in spikes to [whatever] 8, the average will change.
Case in point. Dinner out tonight, I’m 4.4 BG according to meter, my wife is 5.0. She does not have T2D. 45 minutes after first bite, I’m 7.4, she is 5.2. Two hours post, I’m 5.4 and she is 5.0. Taking into account error margins, clearly shows the food was a challenge for me.
We split the entire dinner between us; ate and drank the same.
That for me was not ideal, and will have increased my hba1c. I suspected as much as I wanted a little rice with our Thai feast. My levels have been low to this point, so was prepared to take the hit.
This spike will increase my hba1c reading. Keep doing it and it will increase. Keep at it and watch the levels hit T2D again...
Apologies to OP that I’ve hijacked this a little, but couldn’t let that comment stand unchallenged.