Bananas are a naturally efficient and convenient food for runners to use as fuel. Their high carbohydrate content makes them good sources of energy. They're rich in potassium and magnesium, minerals that runners lose as they sweat. They also have chemical properties that help control stomach pain from nerves and reduce a runner's risk of diarrhea. Bananas are easily portable, so runners can carry them during endurance events such as half marathons. A half marathon runner should incorporate bananas into his race-day meals before, during and after the race itself.
Eat a balanced meal several hours before the half marathon begins. This meal should include a banana, whole grains and a lean protein source such as turkey or low-fat dairy.
Prepare for the race by eating another banana half an hour before the event begins. Substitute a different sort of fruit if you prefer. Eating a piece of fruit during the hour before the race gives you some quick-release energy to get you started.
Consume more carbohydrates such as bananas, other fruits or energy bars every 30 to 45 minutes during the half marathon. Drink water or an electrolyte sports drink at the same time. According to the American Dietetic Association, this helps transport the energy from the carbohydrates to your muscles.
Replenish your body after the half marathon by eating a banana or other carbohydrate source and a protein source together. Eat these within half an hour of finishing the race to prevent your blood sugar from dropping and to help your muscles recover after the exercise.