Simple carbs, familiar food and nothing new on race week. The night before is not the time to experiment.
Keep it simple
White rice, pasta, potatoes or bread with a little protein. Go easy on fibre, fat and spice so your stomach is calm in the morning.
Hydrate early
Drink steadily through the day before rather than a litre at bedtime. A pinch of salt or an electrolyte tablet helps you hold on to it.