Check blood sugar - When is 2 hours after meal?

Everything says to check blood glucose 2 hours after a meal, but when exactly does that 2 hours begin. I typically do it 2 hours after I take my insulin, so if I am high, I wait to eat until my blood sugar has dropped. I read something that says you should check BG 2 hours after your first bite and your meal should never last more than 30 minutes. They said that way you see how your body is reacting to the food.

What do you find to be the most correct or works best for you?

My pump reminds me two hours after I give myself insulin.

I think as long as you are consistent, it really doesn’t matter that much. Your main goal would be have comparable data so you can make accurate changes if necessary.

I was told to test 2 hours after the first bite, so that’s usually what I do. Sometimes I test at 3 hours to know what’s going on. I think the reason for testing at 2 hours is because that’s typically when food is fully digested (unless the food is high fat or a lot of protein) & also when rapid acting insulin peaks.

Of course, timing of insulin to meals is critical. How much time is there between insulin & eating?

The 2 hours should be counted starting with your first bite of food.

If you’re testing 2 hours after a meal in order to figure out if you are giving enough insulin for the amount of food you eat, it would be more accurate to count only meals at which you began with an on-target blood glucose.

Otherwise, you have to consider thecorrection dose and the extra time waiting for the high to drop. That may not give you a true picture of how the insulin and food are working together.

Michael’s point about being consistent is an important one. As we run all these mini science experiments on ourselves, it’s important to eliminate as many variables as possible, to make the “experiments” consistent, and to do them a few times before making changes (because try as we might, it’s REALLY difficult to control all the variables). Best wishes!

I guess I should have specified that I am wonding about abnormal blood sugars before meals.

Normally, I take my insulin within 5 minutes of taking my first bite.
If my blood sugar is above 180, I will wait a half hour, probably, before I begin to eat. If it’s higher, I wait longer.
If my blood sugar is below 70, I usually take my insulin about 15 to 30 min after I start eating the carb part of my meal, depending on what I am eating, and how low I am. (I have had lows during meals because my insulin starts working before my carbs do.
My sugar drops between 55 and 85 units per unit of insulin at dinner time, depending on the time of the month.) See, if I check at 2 hours after my insulin, then I know I have about 70% of my humalog left, and then if I have taken too much I have time to correct, and if I undershot, I haven’t been out of range too long. I thought part of why the 2 hours should start when we take insulin is because it’s easier to calculate one set insulin time.

Maybe it doesn’t matter if I am consistent.

I have gastroparesis (delayed stomach emptying), so I inject after I eat. Throws everything off! Took months of experimenting & lots of testing to figure out when to inject, not that I’ve got it right yet. Because rapid acting works too fast in relation to my disgestion, my endo switched me to Humulin R. It lasts longer & works more slowly. Might be something to discuss with your doctor because your situation sounds similar to mine.

If we had textbook diabetes, testing at the two hour mark of eating to coincide with the peak of most insulin would work. But, you know what work best for you.

Why don’t you correct the highs rather than wait?

Hi! I check my b/s breakfast and two hours after , lunch two hours after , dinner and two hours after and if i have or need a snack and two hours after. Or if i feel to low or high just to make sure

Im a type 2 and the schedules that works for me bests on checking bg are: Upon waking up in the morning before breakfast, then two hour every after meal time, 1 hour after a do my daily exercises and before I go to bed at night.

I do correct highs, but if I check 2 hours after lunch, then I am sometimes either low or high before dinner If I am high, I wait to eat so the insulin has a chance to bring my blood sugar down to a reasonable level before the food makes it start to go up again.

How far apart are your meals? Going with the usual 4 hour recommendation (not that this is always possible!), your insulin from lunch should be just about gone by dinner & not lowering highs much by then. If your BG before dinner is 180 & above, then your lunch insulin dose isn’t enough or your basal dose needs adjusting.

I get crazy numbers like these sometimes because of delayed stomach emptying & all I can do is correct or change timing of injections yet again, though typically my highs are after dinner. Lows after eating followed by highs many hours later is the pattern of gastroparesis, unless you’re eating high fat or high protein meals that take long to digest.

I rarely test 2 hours after a meal, but I often wear a CGM so it tells me if I am still lagging with a high blood sugar and then I can decide whether or not I want to give more insulin or see if the remaining amount will bring me down (insulin can take 3-4 hours to actually finish working and leave your system, but it depends on who you are). I test before my meals, usually in the mid-afternoon (if I remember while I’m at work) and before bed. Also before and after exercise. Average is 6 times, but sometimes more, like 7 or 8.

I’ve always been told to test 2 hours after beginning the meal. Apparently, the two hour mark is when your blood sugar peaks after eating (unless you’ve got gastroparesis or esophageal motility problems), and the idea is to see how high your peaks are.


Thank you. That is the information I was hoping for. If that is when the food peaks, that makes the most sense.

I basically check before breakfast. lunch. basketball practice. dinner. bedtime.
and if I get to feeling low or high, or if my parents, teachers, or friends tell me too if I start acting funny.

I guess I sound like your typical teenager.