Wouldn't mind know if this is just me, but I work out 6 days a week and have a good diet.. I go off and on of gaming months at a time, but ever since the Vita came out, I started to go after trophies for the Vita and PS3 (I use to be an achievment whore on the xbox) now I just want to eat constinantly while I go for trophies and I play games on my ps3 and Vita.. This happen to anyone else lol? Its like gaming is a drug and it makes you have the munchies!
Just like working out, gaming uses a lot of nutrients, but more importantly minerals.
Your body is reacting to the need for rarer nutrients and minerals found in foods, less protiens, fats and starches, and more sugars, salts and others needed for communication in nuerons. Brain must be fed. I find havign a lot of raw veggies and fruits (not sugaring ones like oranges and apples, but more complex ones like cranberries) around helps keep me from piling on the pounds.
You are obviously more health conscious then I am am (I know what a gym looks like from the outside... thats about as good as I get) but if you look up "studying smart diets" or "diet for studying" will give you a good idea.
Basically, B vitamins, minerals (Iron, molybdenum, zink), omega's all are good for the brain drain of playing vid games. All your body knows is it is being drained, and while gaming it is hard to get passed the "shovel in junk till the hunger goes away" response. Just stock healthy crap that doesn't need prep. My healthier friends use power bars a lot, but I prefer soemthing with better taste/texture then hardened cardboard.