No, ok let me explain..
When normal people's blood sugar increases, their pancreases are strong enough to moderate the level of blood glucose in the blood quickly, so although their sugars might rise quickly, they go down quickly too...
What i experience, and I'm sure a whole lot of you is that my pancreas is a little lazy <img src="i/expressions/face-icon-small-tongue.gif" border="0">...so that when my blood sugars rise..my pancreas compensates too late..and produces insulin longer than it should, resulting in me crashing. The higher the blood sugar is at say 1 or 2 hour post meals, the bigger the crash. SO, if caffeine increases your blood sugars, then you tend to crash more, hence why it happens to me a lot in the morning (when i drink coffee).
Make sense?