1 hour 2 hours?? Start or end?

[SillySallySo]

Could someone please clarify when I'm supposed to test after a meal?
It says to test 2hrs after a meal but do I start the 2hr countdown from the moment I start eating or when I've finished eating?
Thank you.

 

[Leadinglights]

Could someone please clarify when I'm supposed to test after a meal?
It says to test 2hrs after a meal but do I start the 2hr countdown from the moment I start eating or when I've finished eating?
Thank you.

Test just before you eat and 2 hours after the start of eating. Paired reading are more useful as you are looking for no more than a 2-3mmol/l increase or no more than 8-8.5 mmol/l 2 hours after the start of your meal.

 

[SillySallySo]

Test just before you eat and 2 hours after the start of eating. Paired reading are more useful as you are looking for no more than a 2-3mmol/l increase or no more than 8-8.5 mmol/l 2 hours after the start of your meal.

Thank you, I really appreciate your answer.

 

[PerSpinasAdAstra]

The two hour test is a great, affordable way to compare between foods and meals. It's not perfect but for the price of two test strips you get a very useful snapshot of how quickly your body is eliminating the glucose from your blood after eating specific foods. I say it's not perfect though as it doesn't quite capture all that might be going on during those two hours.

These three edited screenshots from a Freestyle Libre 2 CGM illustrate how the two hours test is a good but somewhat imperfect test. These are three different breakfasts I ate during my Libre free trial period. Bear in mind these graphs are unique to me, the medications I'm taking, and the severity of my diabetes at a specific moment in time, several months after diagnosis by which time I had lost a lot of weight. They are likely not a good reflection of how your own body would handle these specific meals. If you are currently losing weight or increasing your levels of exercise you may find that your own two hour test experiences can look quite different when repeated a number of months later.

The first graph shows how my body responded to a fairly low-carb breakfast (around 20g of carbs) of an omelette with peppers and tomatoes followed by a small piece of fruit, passing the two hour test with flying colours. The second graph, sugar-free baked beans on toast made from low carb bread has almost double the carbs and the two hour numbers reflect that, suggesting this meal is less ideal but as the rise is less than 3mmol/L and as I stayed under 8 mmol/L it just about passes the test. The third graph, a meal with around 69g of carbs actually passes the test better than the beans on toast, but it looks like the only reason that happened is because I went for a walk while I was digesting the meal. A increased portion of the glucose entering my bloodstream was likely going straight to my muscles as a result of the effects of the exercise.

The conclusions I've drawn from these tests are: 1) I should avoid a bagel for breakfast entirely but it is just about acceptable if I walk off some of the carbs as I digest them. 2) The beans on toast meal is less than ideal but is probably quite good if I have an opportunity to go for a half-hour walk afterwards. 3) The omelette (and probably any breakfast of 20g of carbs or less) is perfectly fine for me, walk or no walk. The Libre and other CGM devices are very expensive though and you only get one 14 day free trial. The two hour test is much cheaper, and the numbers do provide a good picture of how a person handles specific foods and meals. Depending on your daily pattern of eating and activity though it is worth recording the time of day a meal is eaten and any exercise that occurred in and around that meal time, and taking those factors into account. It is also worth bearing in mind that changes over time such as big changes in body weight or exercise, and any changes to medication, will likely have a considerable effect on your response to different foods and meals. For this reason it is probably worth re-testing after a few months if big changes have happened in the meantime.

Best of luck! 🙂

 

[ianf0ster]

Some carbohydrates affect Blood Glucose faster than others and affect different people differently. Thus information about how a particular food affect another person is almost meaningless in deciding if it is suitable for you!
The reason we tend to use the 2hrs after start of the meal is because:

A). In a non-diabetic person, the BG at that point would be back down to what it was before the meal pretty much regardless of the GI and carb content of the meal. - This is what we Type 2's aim to replicate by controlling the carbs we eat.
B). The 2hr mark is a good compromise between fast digestion of carbs (1hr or less) and slower digestion of carbs (perhaps up to 3hrs or more). Note that the time taken depends both on the complexity of the carb, how much fat is consumed and at what time of day it is eaten amongst other factors.

 

[rebrascora]

A). In a non-diabetic person, the BG at that point would be back down to what it was before the meal pretty much regardless of the GI and carb content of the meal. - This is what we Type 2's aim to replicate by controlling the carbs we eat.

Do you have a reference for that as I am not sure it is the case otherwise non diabetic people would have graphs which went along horizontally, blipped for each meal for less than 2 hours and then went horizontally to the next meal and I am not sure I have seen graphs like that. To my mind BG wanders about much more than that.

 

[Dave_Z1a]

I was told some perfectly healthy non diabetics can be high 8's two hours after a meal on a regular basis; not a statistic I follow and try to be high 7's max, taking comfort that when occasionally over indulgent or simply in a "stuff it I'm eating a whole one" or suchlike mood I console myself knowing the high 8's can also be perfectly normal

 

[ianf0ster]

Do you have a reference for that as I am not sure it is the case otherwise non diabetic people would have graphs which went along horizontally, blipped for each meal for less than 2 hours and then went horizontally to the next meal and I am not sure I have seen graphs like that. To my mind BG wanders about much more than that.

I was just commenting about BG measurements and food.
I didn't mean to suggest that BG in anybody is a straight line between meals. It can't be because energy (ketones or glucose) is used up by our resting metabolic processes (brain is the biggest user and certain but not all brain functions actually require glucose). Also, muscles use energy, so exercise has an effect. Meanwhile, in most people, when energy is low, the liver will produce more glucose and release it into the bloodstream. This includes the well-known situations of Dawn Phenomenon and Foot On the Floor. That glucose can either come from stores in the liver or be produced from fats (or proteins) even if no carbs are eaten.

This production of glucose from fat or protein is the mechanism which enabled Type 1 Diabetics to just about survive for a few years in the days before Insulin became available.

 

[rebrascora]

Yes, sorry, I didn't put my point across very well at all. What I was trying to say is that non-diabetic people don't go up after meals and always come straight back down to their premeal level in 2 hours and saying suggesting that can give Type 2s an unrealistic expectation of what they are aiming for. I think some people are already putting too much pressure on themselves to keep their meal rise below unnatural levels and worry if they go above 8, or they are not back down to 5 in 2 hours.

 

[ianf0ster]

Everybody deserves as good a T2 Diabetes control as they can get, but if diet won't do the trick then medication should (also) be used. Remission is not something for everyone, in fact I have never seen a study with medium term results better than around 60%, and that is 60% of motivated people. Even so, that's a heck of a lot better than the 0% that the NHS assumes!

Is that putting pressure on people? As has already been said, though not repeated by me, the aim for a Type 2 is for the BG to be lower than 3.0 mmol higher at the 2 hr mark. My actual target for my remission was 2.0 mmol the same as most others in that other forum (where I started), but here people tend to be more relaxed about higher BG. Similarly, in here people try for a maximum (2hrs after first bite) reading of 8.5 mmol and in the other forum 8.0 mmol is more common.