On the day of a race, choose to fuel up with a balance of fat, and both complex and simple carbohydrates. My race-day breakfast is always Sweet Potato pancakes and a banana. I have included the simple 2-Ingredient Recipe. Another good option is toast with peanut butter, honey, and banana or you could also experiment with different options like making porridge out of 1 cup of cooked quinoa, 1 cup of sweet potato, and 2 Tablespoons of honey topped with a sprinkling of sliced almonds
To help avoid any digestive issues omit any hard-to-digest foods, such as vegetables. Yes, this is the one time no vegetables, but load back up on them after race :)
Make sure you also experiment and find your race day meal of choice on your big training days.