Since my test was at 8am (and my long runs usually start at 8am), I woke up at 6am, had my coffee, water, and a Luna bar. Got to the test center around 7:45 and ate two Clif Bloks (cola, which has a few mg of caffeine).
After the AWA, I had 2 Bloks, a few sips of water, bio break (just in case), and a few jumping jacks to get the blood flowing. I felt like an idiot doing jumping jacks in the bathroom, but it good the energy going and the nerves out.
Between the Quant & Verbal, I took a Clif Shot (same as Gu, just different brand) and some water. Went to the bathroom, did a few more jumping jacks to shake out the jitters.
Nice and light but I still get the calories & miniscule jolt of caffeine I need to prevent fatigue. You should definitely try this out before you go to the test center, though. I know that certain flavors cause GI distress with certain people. And unless you're used to taking Gu shots, it'll take a while to get used to. Sweet snot.