What should I consume if I won't be eating/sleeping for 3 days?

Crazy question I know. All I'll say is, fraternity pledge. So what is the absolute best thing to eat/drink today if I won't be eating or sleeping for 3 days/2 nights out in the sun with strenuous exercise? Pretty sure we get water so dehydration isn't a concern. And what should I eat right before it starts? Huge meal? I was thinking of just eating Subway from here until tomorrow. Wow this is going to blow.