Your body works to maintain fairly steady level of glucose, but sometimes your glucose will rise above baseline (or from where your body views as optimal). As your glucose rises, your pancreas will release insulin to trigger your cells to take this rush of glucose and use it for energy (either in the moment or later). As glucose is cleared from circulation, you’ll notice a decline on your glucose graph. Occasionally your body will overcorrect a spike and release too much insulin. This reaction may cause your glucose to dip below its starting point, sometimes called a glucose "crash". Glucose crashes sometimes result in feelings of hunger or drowsiness.