Pre-competition eating habits

Greetings all! I'm a recreational-level Masters swimmer who's been going for nearly a year now. I swim a mere 2x a week, 1hr a workout, and generally finish less than 5KM a week. This is fine for me, swimming is a hobby for me, and it fulfills my "hobby" requirements quite nicely. I do, however, like to have goals, and distance goals just don't cut it for me. I decided that my main goal was to compete regularly, and to fill my event card, eventually, with times from 17 or 18 different events. I want to do my best when it comes down to swim meets and being timed, and coincidentally, I also want to improve my (currently shoddy) eating habits, so I figured I'd come to others who might know... What kinds of foods should I be eating the week before the competition? What kinds of foods should I be avoiding? I would assume that McDonalds and the likes is assumed - but how harmful are things like chocolate and high-sugar foods, aside from the fullness they give you and the lack of other foods you consume as a result? If anyone has special meals they like to eat before competition, and they don't mind sharing the logic behind the meals, I'd really appreciate the info! Jill Some Chick's Life