Actually, thats odd. I was thinking about this the other day. I think I might actually fall into that category, of drowsiness, but I'm not exactly sure.
I typically get 8 and a half hours of sleep, which tends to be great for a university student. I wake up in the mornings about an hour and a half before class, eat a sufficiently large breakfast, and then drag my up of coffee to my 8:30 am class.
But since September I've noticed that after I consume my coffee, about 15-30 minutes later I start to get sleepy all over again. At that time I've learned to consume copious amounts of water, and halt the drowsy feelings.
I initally thought that perhaps it was just me getting up to close to classtime, or the class itself not interesting me. But, then the other morning, (Monday of all times) I forgot my coffee, and didn't get the sleepy feeling. So, i'm not sure.
I'd believe someone if they told me it was my consumption of caffeine. But, let's hope this is my imagination, otherwise my next cutting cycle could be a bit of a bitch.