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Remember that the information presented here is not intended to replace the care of your own doctor. Before making any changes in the management of your own illness, you should consult your physician or other qualified medical professionals.
Question
I have been trying to get the answer to this question from various sources (including doctors, registered dietitians and pharmacists) and keep getting different answers. Can you clear this up for me? What's the difference/importance of taking post-meal blood glucose levels at one hour versus two hours after eating? Half the sources say do it one after; the other half recommend doing it two hours after. Which should I be doing? Why?Answer
The reason you get different answers is that there is not a clear consensus.The "two hour" after a meal mark, I think, comes mostly from one of the definitions of diabetes (serum glucose level more than 200 mg/dl [22.2 mmol/l] at the two-hour mark during a formalIn addition, for those patients on the rapid-acting insulins (Novolog or Humalog), given the onset (less than 15 minutes) and peak actions (approximately 90 minutes) of these insulins, it makes some empiric sense to test the glucose two hours after a meal to assess whether the insulin-to-meal ratio was properly balanced/estimated.
There has been more written about over the past years of the importance of "glucose excursions" after meals in the overall scheme of diabetes management. So I think that is where the one hour after meals checks have come in.
So, depending on your own meal plan, activity levels, medication dosages, and preferences from your diabetes team, it may not make a clinically important difference as to when you check glucose levels after meals. However, I think that if you take NovoLog or Humalog (by injection or via a insulin pump) with your meals, the two-hour check makes a bit more intuitive sense.
I personally prefer to have my patients check their blood sugar one hour after a meal. There are two reasons. First, I think it is more convenient and less likely to be skipped. Secondly some patients have a rapid spike in blood sugar that will return to normal by two hours. Thus, there is a risk of missing some hyperglycemia.
Please note that the timing of the one or two hours period typically starts with the first bite of the meal, but check with your diabetes team to see if that's what they want you to do.
