Energy drain from RGPU-95

I like the effects this gives me. Generally, more focus when studying and a better capacity to organize my thoughts and choose my words as I'm speaking. Neither of these is really a problem for me normally, I just notice the improvements when I'm using this. My problem is that I feel like I've used all my fuel after a few hours. I'm not normally hungry or sleepy during the day, after some heavy thinking on RGPU-95 I am famished, and I need a power nap.

Are there vitamins or other supplements I could take to help with the extra fuel this extra processing power is using up? Or is something else going on? I just feel like more mental work = more fuel cost, and being hungry and sleepy seems to back that up.