I’ve found that the best thing for thinking is tea. I use it most often when writing, because it gives me something to focus on when contemplating my next plot development.
Aside from the fact that I like the green tea flavor in many things (the tea used, as I understand it, is matcha, which is Japanese), tea is good to consume in large quantities without any weight gain (aside from say, cookies). Two of the main types I drink are black, like Earl Grey, or a Breakfast tea, which is good for waking up or green or white, is good for thinking.
I say this now, because Dustin and I visited Tea Zone (and Camellia Lounge) today in the Pearl District in Portland (which apparently hosts a music jam every Tuesday night). We each ordered a pot of fine tea – I got a Chinese green and Dustin a pot of an Indian silver tip. A bit expensive, but worth it. The tea was served with three minute hour glasses, marking the time when the tea was ready to drink. I should get my dad one of those, so that he doesn’t have to set the timer on the oven and then someone (usually me) has to get up and turn it off.