We're always happy to help navigate life with diabetes, thus our weekly advice column known as Ask D'Mine. It's hosted by veteran type 1, diabetes author and educator Wil Dubois, who brings in-the-trenches experience from both the patient and educator viewpoint.

Today, he's talking shop with a colleague who's an aspiring educator herself and is trying to get the "real story" behind blood sugar numbers at mealtime. Take a read... and let them know what you think.

{Got your own questions? Email us at AskDMine@diabetesmine.comom}


Krista, CDE-in-Training from Arizona, writes: Hi Wil, I just loved your article on Smart Monitoring in this month's Diabetes Self-Management Magazine. I am on my way to becoming a CDE and I hope you will consider my question: I understand that the goal is to make a person aware of what changes with their blood glucose before and after meals. However, can you tell me of a guideline where a certain number range is preferred? For example if a person has a pre-prandial number of 175 and a post-prandial of 225, how concerned should they be? We know that both their before and after numbers are high but is there anything in the literature where a recommended range is given, for example is a more than 50-point jump considered dangerous (increasing risk for some complication)?

Wil@Ask D'Mine answers: That's so awesome, thanks for joining our party by working toward to become a CDE! (Certified Diabetes Educator, for those who may not be familiar.) And thanks for you kind words about Smart Monitoring, but I'm just the reporter. Boy, I wish I were as smart as Dr. Bill Polonsky of the Behavioral Diabetes Institute — he's the super-genius who came up with the concept and coined the elegant term "testing in pairs" to make it easy to understand.

Before I get to your question, let me take a detour for those of you who are new to this concept by playing a quick mind game. Let's say you test your blood sugar two hours after lunch and you get a reading of 339 mg/dL. What does that tell you about your lunch?

Wrong question.

You don't know a damn thing about your lunch. You only have one reading, and one reading is devoid of value, as it has no context. What do I mean by context? Consider one additional piece of information: What if I now told you your blood sugar before lunch was 300 mg/dL? Now what do you know about your lunch? Well, you know that you have one hell of a problem, but that lunch has nothing to do with it.

Welcome to the power of testing in pairs. One number tells you nothing. Two numbers tells a story. And stories are powerful.

I think the biggest problem in blood glucose testing is the stand-alone fingerstick test. People with diabetes are not being taught to test in pairs, and the damn insurance companies are not giving us enough strips to do it. There will be no widespread control of diabetes as long as insurance plans (and the government) refuse to provide enough test strips for pairs testing around all meals and exercise.

That's because stand-alone tests not only miss important information, but they also sometimes leave people barking up the wrong trees. People look at high Post prandial spikestand-alone numbers and often cast the blame in the wrong direction. Just a few weeks ago I had a lady in my office telling me how much she missed eating watermelon, which she hadn't had for years. Huh? As watermelon is really mostly water and pretty low-carb, I wondered if she had some kind of crazy food allergy to melons and asked her about that. "Oh, no," she told me, "It makes my sugar shoot up crazy-high. Watermelon is bad for me."

Black hat watermelon. Cue the theme from The Good, The Bad, and The Ugly.

We had a little talk about testing in pairs and I sent her away with a prescription to test, record, eat watermelon, set a two-hour timer on her smartphone, test again, record results, and check the point spread. She's now eating a small of slice watermelon every day, making up for lost time.

Now, to answer your question on preferred glucose range within the pair: There's no science, no studies, no literature giving us a definitive answer. It all depends on whom you work for.


It's true.

Let's say you end up working for a practice that uses the American Diabetes Association guidelines. The ADA calls for fasting blood sugars to be between 70 and 130, with postprandial readings below 180 mg/dL. So that's a 50 to 110 point allowable spread. So any point jump under 110 points is a controlled and acceptable excursion, at least by ADA guidelines. If you worked for an endocrinologist using the American College of Clinical Endocrinologists (AACE) guidelines, you'd have a narrower allowable range.

Personally, as I work with a lot of insulin users, I'm pretty uncomfortable with fasting blood sugars as low as 70, so we use 100 mg/dL as our fasting target. I generally tell my patients that any excursion under 80 points is a good meal. Well, a good match between the meal and the therapy, anyway. There's no good and evil on the dinner table.

But it really doesn't matter what range we use; it's splitting hairs. The gospel truth is that "excursions" are normal, and that if they are mild, they are harmless. The goal of 50% of a diabetes therapy plan is to keep excursions around meals at a tolerable level, and I doubt it matters much in the long run if the level of those excursions is 50 points or 80 points.

So no matter how high the second number in a pair is, I don't think a patient should be concerned about the rise so long as the point spread is within the limits that you (or your healthcare professional) choose to use. At this point, the PWD should be happy and secure in the knowledge that the med and foods are working together.

Of course, spread and altitude are very different things. Spread only measures how a given meal, snack, or event affects the blood glucose level. If the pre-meal number is out of range, then there is a problem that needs to be fixed, but it has nothing to do with the meal.

And that's the takeaway message here: You need to control both the fasting state and the meal excursion, but you use different tools to keep them both where they belong.

When it comes to complications risk, this begins to get complicated. You are correct that the higher the pair, the more likely it is that we are asking for trouble, but we need to freak out over the right things. No point jump that's within range is inherently dangerous in terms of being a direct cause of complications. We need to be clear on our goals, and not put the blame on the wrong actor. So long as the rise is in target, it does not matter how high it is: 50% of the therapy plan is working at that point, so we are halfway home.


This is not a medical advice column. We are PWDs freely and openly sharing the wisdom of our collected experiences — our been-there-done-that knowledge from the trenches. But we are not MDs, RNs, NPs, PAs, CDEs, or partridges in pear trees. Bottom line: we are only a small part of your total prescription. You still need the professional advice, treatment, and care of a licensed medical professional.

Disclaimer: Content created by the Diabetes Mine team. For more details click here.


This content is created for Diabetes Mine, a consumer health blog focused on the diabetes community. The content is not medically reviewed and doesn't adhere to Healthline's editorial guidelines. For more information about Healthline's partnership with Diabetes Mine, please click here.