Spikes.

the word "Spike" in this context, just describes the shape of the graph you would get if you plotted continuously measured blood glucose.
Spikes do occur in non-diabetics, but they are probably less pronnounced and eliminated quickly.
A little bit of info that many people haven't come across is that non-diabetics with slightly elevated HbA1c are prone to the same health issues as diabetics, eg cardiovascular problems.
It's now thought that a glucose level of above 7.7mmol is what does damage. If spikes are happening, above that level and especially if it takes a while to get them down,damage will happen somewhere. Unfortunately, it often doesn't show up in HbA1c tests
I like to make sure I stay below 6, even after meals, to protect myself as much as possible
Hana