What to Eat and Drink
Nutrition principles dictate that you should always stay well hydrated, whether you are exercising or not. In particular, drink ample fluids in the days prior to competition, regardless of how long the race may be, what the weather is like the day of the race, whether the course is particularly hilly, or other conditions of the race.
For workouts and races that last an hour or less, you need only drink water every 25–30 minutes to stay well hydrated. Although sports drinks do play an important role during runs lasting an hour and longer, they won't necessarily give you a performance edge for shorter workouts and events such as the 5K. Consuming sports drinks can be especially helpful when training in hot and humid conditions, however, as they refuel your body's electrolyte stores.
Eating Before Race Day
Carbohydrate loading and eating in general is a major consideration in running, whether to fuel your body for training runs or for a road race. However, you really don't need to load up too much on carbohydrates the day or two before a 5K, not in the same way you do for a marathon.
Don't stuff yourself, thinking you're just going to burn off the calories the next day. And don't eat new foods you haven't eaten during your training. Many a runner has regretted the time he decided to have exotic or unfamiliar food the day before a race. Eat something you know will agree with you. Otherwise, regardless of your pace, the consequence of poor nutritional choice can be discomforting and perhaps even embarrassing.
If you're like many runners, you live for your next meal. Well, plan your eating extravagance for the night after the 5K. Leading up to the event, be mindful of any unnecessary fat, sugar, or other nutritional bombs that might put you in the bathroom instead of on the starting line come race day.
In summary, your evening meal the day before the race should consist of well-balanced and simple foods that you know will cause no digestive troubles. Avoid foods that are high in salt, fat, or are fried. You also want to limit your intake of foods with high roughage content, such as salads, vegetables, and cereals.
Drinking Before Race Day
As stressed throughout this book, stay well hydrated. If you enjoy beverages that contain caffeine such as coffee or tea, be aware that drinking these in late afternoon or evening may make it difficult for you to fall asleep easily, especially if you have pre-race jitters. Additionally, alcoholic beverages are diuretics that can contribute to dehydration.
At the other extreme, if you're taking in excessive fluids through water or sports drinks, you may experience hyponatremia, or water intoxication, a condition in which excess fluids create an imbalance between the body's water and sodium levels. This can lead to nausea, fatigue, vomiting, or worse.
Eating on Race Day
Equally important is your decision regarding what to eat on race day. If the race is set for early in the morning (as most 5Ks are), you may wish to bypass breakfast and just stick with water. If you choose to eat a light snack (this could be a banana, slice of toast, bagel, or energy bar), be sure to consume it at least 1 hour before the start of the race.
Try to go to bed early the night prior to the race so you will be well rested for the event. You don't want to be rushed or, worse, oversleep and miss the race. Wake up early enough to eat, make a bathroom visit, and take care of anything you need to do so as not to feel rushed.
Events held during the late morning, mid-afternoon, or evening are more difficult to plan for nutritionally. While you certainly don't want to go hungry in the hours prior to a race or a fast-paced workout, you don't want to eat foods that cause stomach cramps or digestive problems.
Light, healthy snacks are your best approach for late morning and early afternoon races. If the race will be held in the evening, eat a healthy and satisfying breakfast along with a sensible but light lunch (avoid high-fat and fried foods). A piece of fruit or a handful of pretzels are good snack choices later in the afternoon. In short, the best way to determine which foods and fluids work best for you, whether during training runs or races, is by experimenting with these in practice.