It often comes as a surprise to people without diabetes when I inform them that the biggest immediate risk for anyone with Type 1 diabetes is not high blood sugar, but low blood sugar.
Me: I need some sugar, I’m running low.
My well-intentioned but misinformed companion: You can’t have sugar, you’re diabetic!
“Can’t have sugar” is the CliffsNotes version of diabetes that most of the world understands, but we know it’s a far more complicated and nuanced condition than a simple prohibition on eating cookies. We have to be masters of physiology. We have to understand how ALL the foods we eat interact internally and how those interactions affect the rise in our blood sugar. And nowhere is that more important than when we are dealing with hypoglycemia.
Now, I have committed the sin of treating a low with a brownie or a candy bar before. We all have. It’s just so tempting! I mean, when else can you say, with ANY truth at all, that you have a medical need for dessert?!?
“I’m low, give me another slice of pie!”
“Looks like I need some ice cream!”
Our health-care providers, educators, and all the literature in the world tells us we should treat a low with glucose tablets, juice, or another source of straight, fast-acting glucose rather than these other indulgent (and generally high-fat) treats. But why? Why can’t I have a cookie when I’m low? What’s so great about those chalky, OK-tasting-but-not-at-all-exciting glucose tablets? The answer is in the fat!
We’ve all heard of the “pizza effect,” right? It’s that highly annoying phenomenon where we have to split our insulin dose because food that contains a high percentage of fat messes with the absorption of carbohydrates. Specifically, it delays that absorption. When I have pizza, I will see a mild rise immediately after eating, as SOME of that carbohydrate hits my blood sugar. But then, three hours later, it spikes, seemingly out of nowhere! If I don’t split my insulin, I’ll be LOW right after the meal (since I’ve taken the insulin for ALL the carbs, but only about 60% to 70% of them are impacting my blood sugar right away), followed by an unexpected HIGH three to four hours after the meal when those delayed carbs hit (along with a little from the protein) and I no longer have the active insulin necessary to meet that spike!
If we take this knowledge and apply it to that candy bar we’re so tempted to eat when we’re low, the problem becomes pretty obvious. The delay in absorption won’t be as dramatic as it is with pizza (which is LOADED with fat and some protein from the cheese!), but the fat WILL mean that candy bar will take longer to impact our blood sugar than glucose tablets would have. And that presents a few problems.
The most obvious problem with the slower absorption is that our blood sugar won’t bounce back as quickly. If we’re severely low, that’s a real safety concern! Severe hypoglycemia needs a quick response! The other issue is that we’re more likely to overtreat our hypoglycemia and end up too high. The old “rule of 15” doesn’t really work when the carbs we just ate are slow moving. (The rule of 15 for treating hypoglycemia is to take 15 grams of glucose, wait 15 minutes, and retest. If your blood sugar isn’t rising sufficiently, take another 15 grams, and test again in another 15 minutes.) If the carbs are taking 20–40 minutes to really kick in, we might end up taking 45 grams before we start to see the rise, and then it can keep pushing RIGHT into hyperglycemia land as all those carbs finally take hold!
The proof is in the chart!
I’ve been wearing a CGM for the past several months, and I love the thing! In preparing to write this week’s entry, I decided to try a little experiment (and no, I probably shouldn’t have done this, and no, you shouldn’t do it at home!). Having the CGM means I can tell it to alert me when I’m falling below a certain blood sugar level. So I set that alert relatively high, at 75, and took a few extra units of insulin with a few meals to gently push me a little low afterward. When I hit 75 and my phone beeped (the meter sends information to the phone through Bluetooth), I treated the falling number. The first time, I treated it with a cookie, and the next time, with glucose tablets. The results were pretty amazing to see!
When I treated with the cookie, my blood sugar continued to dip for about 10 minutes, then start arching upwards in a gentle rise that tapered off about 30 minutes after consumption. When I treated with glucose tablets, I saw a sharp rise within 5 minutes of consumption, which peaked within 10–12 minutes and then tapered off. Both foods eventually got me to about the same number, but the glucose tablets were about three times as fast! Now, at 75, that wasn’t a big deal. But if I had been 65, or 55, or 45? That lag time could have spelled real trouble!
Does all this mean I will never use a cookie to treat a low? Probably not — I am human, and cookies ARE tasty! But I won’t treat a severe low with anything but straight sugar, and if I do give in to temptation and eat a cookie the next time I’m at 71, I won’t fall into the trap of overtreating when 10 minutes later I haven’t shot back up yet.
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