I only game on the weekends, since I'm really busy all week, so my gaming nights, I usually either order a pizza or will make something easy to put down, like curry rice or a grilled cheese sandwich and soup.
As for snacks, usually cheese or potato chips (and a specific brand that are thick cut and made with olive oil--they're the potato chips for people who don't usually like potato chips), though I'm going to try to start eating dried berries or nuts because those are better for me. I usually drink tea or veggie/fruit juice now that I'm stuck on antibiotics and allergy meds; before meds it was beer and chuuhai (about the same alcohol level as beer, but sweet and flavored).