I mentioned in my last blog post that I was reading a book by Michael Pollan, called In Defense of Food. Since it's a book about food, nutrition, and nutritionism, I found a lot of what it had to say applicable to my type 1 diabetes.
One thing I found particularly interesting was this quote, found on page 112 (emphasis added):
Sugar as it is ordinarily found in nature — in fruits and some vegetables — gives us a slow-release form of energy accompanied by minerals and all sorts of crucial micronutrients we can get nowhere else.
Nutritionists often advise diabetics to opt for naturally occurring sugars, such as fruit, for just this reason: Because of the fiber included in the fruit, the body absorbs the sugars much more slowly, which prevents the rapid peak of blood glucose caused by processed sugars.
(This is also where the Atkins craze got the rather erroneous idea that total carbs - fiber = "actual" carbs. That formula is actually a rather over-simplified way of looking at it, and not quite accurate — the sugars are still there, they just take longer to hit your blood stream. Besides which, you can't duplicate the effect by throwing together processed sugars with a bunch of fiber, like many of the prepackaged Atkins foods do — the lack of processing in the fruit is a significant part of why your body takes longer to absorb the sugar!)
For type 2 diabetics, eating naturally occurring sugars such as fruit is important because it gives your body time to keep up with its insulin needs. For type 1 diabetics, like me, fruit has a slightly different, but rather interesting effect: The delayed absorption into the blood stream changes my insulin needs.
I've found that even though an average-sized apple should typically contain about 30 grams of carbohydrates, 2 units of Humalog will sometimes cause me to dip too low near the end of Humalog's 2- to 3-hour window (Humalog takes between 2 and 3 hours to run its course). I'm guessing that it's because the sugars hit my blood stream so gradually that the insulin ends up being too much.
On the other hand, foods that hit my blood stream more quickly, such as candy bars, sometimes take more insulin than the amount of carbs would indicate.
Although one of the beauties of carb counting is that I can eat whatever I want, whenever I want, it's also good to keep in mind that certain foods foster better overall glucose control.