That particular acronym, standing for Your Mileage May Vary, is all too common on the insulin-pumpers’ website.

It applies to those of us with any chronic disease, and one of the main problems with “evidence-based” medicine is that it tends to rely on how the “average patient” reacts. There is no such animal as an “average patient.”

I had first-hand experience of this when a doctor, pre-pump, tried to put me on what he called a sliding scale of insulin, and gave it also to nurses in the local hospital. They insisted on using his scale when I was in the hospital for something else. I looked at the dose of insulin they insisted was necessary when my blood sugar was a little high at bedtime, and said “that’s going to put me into insulin shock.” They insisted on giving me the dose anyway. Luckily insulin shock still woke me up back then, and at 3 am I woke up shocky, hit the call button, and demanded a snack for insulin shock. They insisted on checking my blood sugar first, which only confirmed what I had tried to tell them earlier. I know now that that particular sliding scale, which was probably worked out for the average diabetic of my weight, simply did not work for me. I am very insulin sensitive, and while I absolutely need insulin and will see a very fast and uncontrolled rise of blood sugar without it, I need a very small amount, given my weight.

It isn’t just person-to-person differences, either. It can be time of day, time of month, stress, air bubbles, absorption rate of injected or infused insulin, or just the natural cussedness of the universe. Sometimes it can be how what you eat gets into your bloodstream.

Your blood sugar does not rise the instant you put carbohydrates into your mouth. The food has to be chewed and swallowed, as almost nothing is absorbed directly from the mouth or esophagus. It has to reach the stomach. One of the side affects of diabetes in many people is gastroparesis, which is delayed passage of food through the digestive system. To further confuse the person trying to keep diabetes under control, this delay is highly variable.

As a general rule, food I eat at breakfast time gets into my bloodstream, as glucose, fairly quickly. I’ve taken to eating yogurt for breakfast because most of the carbohydrates are lactose, which absorbs fairly slowly, and because the relatively high protein content also slows absorption. At noon my food absorption is a little slower, and by dinner time it’s slower yet – slow enough I normally spread my insulin out over 4 hours or so.

Changing my eating habits, as I did two days ago for Thanksgiving dinner, can cause an unexpected change in how fast the dinner actually gets into my bloodstream as glucose.

I didn’t have a huge dinner, or an unbalanced one, but I had more than normal, and upped my pre-meal insulin to compensate. I kept to a four-hour dual bolus, but by the time we went to another house for dessert, my blood sugar was running low. We had pie for dessert. I had a small piece, and I was still low, but I did take more insulin to balance the pie.

By the time I got home I was well into insulin shock, with a blood sugar below 50, and over the next two hours I ate enough to bring it up to normal by bedtime.

Four hours later my blood sugar was over 300.

I’m pretty sure that what happened was that the relatively large dinner caused more than the usual delay between swallowing food and the actual rise in blood sugar. As a result the amount of insulin I took, which was reasonable for the amount of food I ate, was enough to put me into insulin shock. Later that night the food caught up with the insulin, but by that time I had eaten enough extra to treat the shock earlier that my blood sugar went high.

The only way a doctor can prevent this is by insisting that you eat exactly the same meals at the same times every day. But we’re people. Most of us can’t keep up that kind of regime. And if we don’t accept that rigid a regime, we have to be intelligent enough to treat ourselves, to a certain extent.

I’ll probably do the same thing for Christmas dinner. But I’ll know to spread the insulin out over more than 4 hours.