I know that if you are told the wine is expensive it tastes better, but to actually have a biometric influenced so easily by perception is surprising. To keep this in context, this was a study done on type 2 diabetics who were misled by deceptive nutrition facts labels. We therefore cannot generalize this to the rest of us unfortunately. Also, I cannot pretend I don’t know that chocolate cake has a lot of sugar.
On a serious note this also flies in the face of the fact that different foods cause your blood sugar to spike, and there’s enormous variability between humans as to what these foods are. I monitor my blood sugar 24/7. Normal pasta causes my blood sugar to go very high, but gluten-free and whole wheat pasta does not. I experience no spike in blood sugar from dark chocolate, while different types of breads have great variability in their effect on my blood sugar levels. In all of these cases I was unaware of what the effects should be on my blood sugar, and yet it had no influence.