I had previously done a self-experiment with blood glucose response after completing a blood donation. That time I had consumed 200 grams of milk chocolate and the effect was that donating blood seemed to contribute to a muted blood glucose response.

In this case I wanted to try consuming a much larger quantity of chocolate – 400 grams. The original intent was to consume 500 grams, but I just didn’t feel like eating that much when the time actually came to it. 400 grams was enough to make my stomach feel queasy.

Another thing that I changed from my original intentions was my meal. I had planned to eat a normal meal along with the chocolate, but my stomach was so full I didn’t feel like it. I found this result interesting in itself. Eating all that chocolate had the effect of keeping me from eating anything else, including the meal that would have been healthy and aided in my recovery from the donation process. I think of this as something of a corollary of Gresham’s Law (for those familiar with economics), but in this case bad food drives out good.

That’s part of what happens in these self-experiments, like life they are somewhat messy and impossible to completely pre-arrange.

Note that chocolate is not necessarily junk food – small quantities of dark chocolate have been shown to have some positive health benefits.

The chocolate used was Green and Blacks milk chocolate, 100 gram bars containing:

  • 522.5 calories
  • 47.5 grams of sugar

Though for some reason on their labeling they give amounts per 40 grams – who eats 40 grams?

The bars were 34% cocoa and sweetened with raw cane sugar, rather than refined sugar.

I also made the measurements more closely together, at 15 minute intervals to more closely track the changes. This is harder on the fingers, but gives a better picture of the physiological changes taking place.

Also notable is how easy it is to consume a large amount of calories in a short period of time. That was 2090 calories consumed during just part of an evening (2.5 hours in this case). That’s pretty close to the caloric requirements for an adult for an entire day.

There was minimal physical activity during the course of the measurements (after I had walked home from the clinic).

So, on to the results. It was striking how initially my readings were very high after having a few snacks at the clinic, though it moderated rather quickly. There were time when my blood glucose seemed to drop fairly quickly. See the data table below.

Note that the snacks, mostly Oreo cookies, contain both refined sugar and refined wheat and perhaps the combination of the two contributed to the result. The pizza would also have contained refined wheat.

Refined wheat + refined sugar vs. chocolate + raw sugar? While I hardly thinks there’s adequate data in this little self-experiment to fully elucidate the comparison, I would prefer the latter. In addition wheat, especially in its refined state, does increase blood glucose substantially.

So here’s the data table with the results.

Note that after sleep the reading was pretty much unchanged, which I found interesting. But then 5.9 is not an especially high reading.

Here’s the graph of the same data.

Note the non-linearity and the ups and downs of the response. The complexity of the body’s feedback mechanisms makes me doubtful of simplistic dietary advice and appreciative of the complexity of the system that we are.