Having a high carb meal should cause a spike, not a low in blood glucose. As to the symptoms of a low I’m not sure. Fortunately I’ve never had one.

My understanding is that those can be symptoms of a low blood sugar crash and yes, you can have a crash after the spike of a high carb meal.That is part of the reasoning behind the BSS to provide a steadier state of carb intake and blood glucose fluctuations without those heavy swings. In terms of the physiological mechanism, I sure am not a doctor but would speculate that n the general physiological reaction to this particular stressor the body is going to mobilize whatever it takes to get your blood sugar up and in that process, these symptoms appear.