Diabetes: It’s Not Just About Insulin-to-Carbohydrate Ratios

Diabetes can sound like a simple problem. The body doesn’t produce the insulin needed to take sugar from the bloodstream and deliver it to the cells. So instead we inject insulin. Match the insulin amount to the food amount, and voila, problem solved. Sure, you might miscalculate sometimes, but then just take a little bit more insulin if you didn’t take enough, or pop a few glucose tablets if you took too much, and you’re good to go, right?

Well, anyone reading this who has had diabetes for more than five minutes (and anyone who KNOWS someone with diabetes) knows better. Diabetes is a complex thing, and blood sugar control isn’t just a matter of following a never-changing, preset ratio. But for all of us, even the veterans, it’s easy to forget just how many variables are going into our blood sugar control.


First, the basics
Getting the medication dosages right is the first step for all of us. Whether that means oral medications, injected insulin, or a combination, there is very little we can do to maintain good control if we don’t first get this part right. Anyone who has gone through the process knows it can take a little time. It’s a matter of working with your doctor, testing out insulin-to-carbohydrate ratios, and reporting back until you’ve nailed down the best ratios for your needs. And it’s not the same for everyone. Your activity level, your weight, your individual genetics, your lifestyle — all of this factors into getting that ratio.

Once you’ve got the insulin-to-carbohydrate ratios correct, it’s a matter of correctly estimating the carbohydrate content of the food you’re eating. In the digital age this has become much easier — most any chain restaurant will have an online guide to the caloric intake and nutritional breakdown of their menu items. This takes the guesswork out, and gives you a much better chance of avoiding the problem of incorrectly estimating your insulin-to-carb ratios. Of course, sometimes you’ll be eating something for which you don’t have that luxury, and you’ll have to rely on your best, educated guess for the carb content of the food you’re about to eat. But with practice, you’ll get to where you can pretty accurately gauge MOST foods without needing a chart for them.

Physical activity, correction factors, and surprising food effects
OK, you’ve got your ratios and you’re accurately calculating what’s in your food. We’re done, right? Eh, not really. Activity has a major impact on insulin absorption. Certain foods have surprising effects on your body’s blood sugar, as well. Finally, you’ll find yourself from time to time in a situation where you’ve got to correct for a high or low blood sugar. All of these have one common element: They all require a tweaking of the ratios!

Exercise causes the body to burn through sugar. So anytime you know that you’ll be exercising within a few hours of taking a shot, you’ll need to take this into account and adjust the insulin component of your ratio down. How far down is, again, something you’ll need to figure out with your health-care team. But the effect doesn’t end when the activity stops. Exercise will increase your body’s insulin sensitivity well after you’re done. In my own experience, I’ve found that exercising three days a week causes my ratios to go down ACROSS THE BOARD. So if I go for an hour bike ride on Monday, my ratio on Tuesday is still going to be a little lower than if I hadn’t gone biking on Monday.

Correction factors, or the drop in blood sugar caused by each unit of insulin, come into play when you find yourself unexpectedly high or low. If you’re low, you’ll need to adjust down if you’re about to eat. If you’re not about to eat a meal, you’ll need to take sugar, usually in the form of glucose tablets, to raise it back up. If you’re high, you’ll need to add a little extra insulin to bring that blood sugar back into range. These correction factors are, like everything else, different for everybody and something that will take a little trial-and-error to nail down.

Finally, certain foods have surprising effects on blood sugar that you might not expect. Alcohol can cause your blood sugar to trend low for up to 24 hours after consumption, so you might want to aim for a little higher number than usual before going to bed (The ADA recommends aiming for 100–140 mg/dl before bed if you’ve consumed alcohol.) Pizza can cause a late surge in blood sugar, and we’ve even coined the term “the pizza effect” in the diabetes world to describe this very common phenomenon. Splitting your fast-acting dose can help with this — taking half before you eat, and half a little after so that you time that second spike in insulin activity with delayed surge in blood sugar. And sometimes, certain foods just behave differently. Anytime I eat Mexican food, I increase my ratio. It doesn’t even seem to matter which dish I eat; if it’s Mexican food, I take a little extra.

We’re not done yet…
OK, now we’re done, right? Not quite. We don’t live in a vacuum with diabetes, and in the human body all parts affect the whole, and vice versa. So in truth, nothing we do is ever truly “unrelated” to our blood sugar. It’s just a matter of how strong and direct the effects are. I’ve often written about managing stress in this blog, for the simple reason that chronic stress unleashes a physiological process in the body that can directly impact our ability to efficiently use insulin. Studies have shown that consistent mindfulness practice leads to a lowering of the HbA1c, our best indicator for overall blood sugar control.

Sleep impacts our blood sugar. Chronic sleep deprivation can increase insulin resistance. And lack of consistent rest leaves us needing more energy, which we will instinctively look for in foods, causing further increase in potential blood sugar. Sleep deprivation is, of course, also a source of stress, and so we see the potential for a “double-attack” here if we’re not careful.

And of course, we all know that weight plays a major factor. This is true for all people with diabetes, not just for those of you with Type 2. The effect is more direct for people with Type 2 diabetes, but insulin resistance happens for those of us with Type 1, as well, and higher weights correlate with increased insulin resistance.

Clearly, good diabetes management is about a lot more than just medication dosages. It can be a lot to think about, and at times it can be overwhelming. But we live in a remarkable age for diabetes care. No, there is no cure yet (and won’t be for at least a while longer), but there are so many resources for us. You’re visiting a great resource right now! On this site there are articles, blog entries, and ideas for almost every situation you’ll face. The American Diabetes Association works around the clock to provide resources, provide education, and improve treatment outcomes. There are support groups, counseling services, and countless diabetes health-care teams out there ready to support you.

Can metformin prevent Type 1 diabetes? Researchers in Scotland are hoping to find out. Bookmark DiabetesSelfManagement.com and tune in tomorrow to learn more.