It’s so important to adequately fuel for a race, whether it be a 5K, 10K, half or full marathon. What we eat has a profound impact on our energy levels, our strength & overall performance.
Since a 5K is a shorter distance, there’s really no need to carb load (cutting back on fat & protein & increasing carbohydrate-heavy foods). Carb loading is really more important for events that are at least 90 minutes in length. The goal is to eat a balanced breakfast of 200-300 calories around 90 minutes before the race. Focus on natural, whole, unprocessed carbs, no more than 10 grams of fiber (it could unsettle your intestines). Examples might include a bagel with a tablespoon of peanut butter & apple slices, oatmeal topped with fruit & minimal, unprocessed sugar (go with Sugar in the Raw) or greek yogurt topped with fruit & granola. The key is to have quality carbs with lean protein.
If it’s a later-in-the-day race, lunch should avoid high-protein or high-fat items because they are harder to digest & they likely would still be in your system longer, negatively affecting your performance. Go with a lean meat sandwich (turkey, chicken) with vegetables but hold off on the mayo. If hungry later, stick with a banana, a low-fat, lower-protein energy bar (Clif Bar has good options).
Most importantly, HYDRATE. Make sure a couple days leading up to the event you are drinking enough water. The goal is half your body weight in fluid ounces (ie: if you weigh 180lbs, drink 90oz per day). If you are exercising daily, increase to 75% of your body weight. The day of the race, stick with the same game plan & have 15-20 ounces of water 2-3 hours before the race & then, about 20-30 minutes out, drink 10 ounces.
The key is to not deviate much from what you do daily. I recall a 5K race I ran years ago where we went out for a spicy Mexican dinner the night before. I was in the blue room (port-potty) 20 minutes before the race & it was NOT fun. I managed to finish well but I’m sure I could’ve done better without having it.
Have FUN, have a simple game plan, stretch (especially the hip flexors & hamstrings), know the race route (elevation changes etc., if you can), do NOT compete with anyone else & RUN YOUR RACE !!!