only time when i'm playing games to the point where i have to get food is when im at a friends house and we'll just grab whatever's in his pantry. and some monsters or mtn. dew if it's there.
I'd say either jello, mandarin oranges, or chocolate, none of them get in the way of the mouth if you are online and have to talk, cookies suck for online play, so try some of those three. Exclude the cookies.
Make sure you peel the mandarin and take it apart. Peeling an orange while playing CoD is very hard.