Why carb counting doesn’t always work

For every complex problem, there is a solution that is clear, simple and wrong.

H. L. Mencken

In theory, it works like this. You weigh your food and check the food database. This gives you the exact carb count for your meal. You dose the insulin according to ratio. For many of us, this is 1:10. If you’re extra good you pre-bolus the insulin to give it time to hit the bloodstream. You expect a nice steady line on your continuous glucose monitor. Maybe a small bump. Only this is not what happens. At all. Instead, you eat and your blood sugar spikes to twelve (216 mg/dl). Why is this happening when you’ve done everything right? You feel like a failure at diabetes and mope. I know I used to.

It’s not you that’s doing something wrong. It’s carb counting. While most doctors present it as a fit-all-solution it fits very few of us. The mantra in the medical community that’s passed down to the patient is that as a type one you inject for the carbs and eat them. This simple equation doesn’t work a lot of the time. There are a few reasons.

First off no matter how good your mathematics is you can’t count carbs with accuracy. In packaged foods, the carb count can be off by twenty percent. This gets worse with fruit and vegetables where the carb content varies by up to fifty percent. Not all apples are created equal, and ripe tomatoes are great for spiking blood sugar. It doesn’t matter how experienced you get with diabetes, this uncertainty remains part of your calculation. 

When you eat a lot of carbs you also require high insulin doses. The greater the dose the greater the potential for error. If you’re taking insulin for fifteen grams of carbs and you’re off by twenty percent the error is minor. If you’re dosing for dinner at eighty grams (as recommended by my diabetic nurse) those twenty percent make a huge difference. High carb is a guessing game. Sometimes you’ll hit the mark and feel a million dollars. Other times you miss, with blood sugar spiking or falling off a cliff depending on the error.

So what’s the solution? It’s to eat fewer carbs for better accuracy. Many diabetics follow a ketogenic diet set out in Dr. Bernstein’s book, with a maximum of 30 grams of carbs per day. I eat a bit more than this at 50-60 grams per day because I like vegetables and my blood sugar allows it. Even on a low carb diet you can eat most things but in smaller amounts. You can substitute high carb foods for things like protein bread, dark chocolate, and these delicious blueberry muffins. Pizza can be made with cauliflower crust and instead of spaghetti, there are zoodles. 

As Molière put it: we should eat to live, not live to eat. This applies especially if we’re diabetic.