"You know the feeling, or maybe you don't- sleepless, hyperactive and completely sick to your stomach at the same time. Most food at conventions and similar events isn't healthy in the least, but you can still follow the conventions of good health.
1. Drink water. Get a nice water bottle. Fill it every couple of hours.
2. Find the food sources! Not just the dealer's room; find a con suite, a snack table or any rooms with particularly charitable con-goers therein. Try and find a fridge if you're bringing your own food. Mark it on your maps.
3. Plan out a budget for purchased food. This isn't a major step, you just need to determine if you'll be leaving the con for a real meal. Don't spend more than 9 dollars a day on snack food or you'll not only go over budget... you'll die from sugar and fat before the con is over.
4. Find noodles, a veggie tray and/or fresh fruit somewhere. Take it with you if you can.
5. Stay sanitary. Wash your hands as often as possible (definitely after using the bathrooms, which are usually filthy).
6. If you're feeling upset or sleepless, make yourself some tea. If you don't like tea or it's too hot, wait until it's cold and down it in one gulp. It will help you calm down.
7. Indulge every once in awhile -- free candy is ok, just not for every meal."