5K runners should eat a light meal before the race that consists of foods high in starch and complex carbohydrates, such whole wheat or multi-grain bread, cold cereal, pasta, fruits and vegetables. The meal should contain approximately 500 calories and be consumed 3 to 4 hours prior to the race. This gives the body enough time to break down these types of foods and absorb the valuable nutrients.
On the morning of the race, runners should avoid foods with large amounts of sugar, which can contribute to dehydration because the body's cells require extra water to digest them. Runners should also avoid foods high in proteins and fats, since they are more difficult to digest.
Runners should also drink approximately 64 ounces of water prior to the race, but avoid drinking water during the thirty minutes before the start. Water consumed too close to the event makes the runner feel bloated and can cause stomach cramps. A small amount of caffeine improves the performance of many runners. Runners that choose to consume caffeine must be wary of dehydration, since caffeine is a diuretic.
No special diet is recommended for 5K runners in the days leading up to the race. The runner should take care to eat a sensible, well-balanced diet. Runners should choose foods they are familiar with on race day to avoid the possibility of having an unexpected adverse reaction to an unfamiliar food.