Marathon Nutrition - Before, During and After the Race

Prior to race day, marathoners need 60-70% of their total calories from carbohydrate, the remaining calories from fat and protein. This carbohydrate loading allows for storage of carbohydrate as glycogen in both muscle tissue and the liver.  Muscle glycogen is the primary source of fuel used in the first 90 minutes of exercise.  After 90 minutes, muscle glycogen stores become depleted and glycogen is released from the liver.  If you do not have proper glycogen stores, you will exhaust yourself and “hit the wall”.  High quality carbohydrates in the form of whole grains and fresh fruits and vegetables are best prior to race day.

A proper pre-exercise meal can improve performance and time to exhaustion, as well as enhance liver glycogen stores.  The pre-event meal should be high in carbohydrates, non-greasy, and easily digested. The amount depends on the time it is ingested prior to the event. Three to four hours before the race, roughly 700 kcal can be consumed safely.  Examples of a 700 kcal meal include scrambled egg whites with white toast, low sugar jam, and a banana.  Other examples include 2 cups plain pasta with a roll, or 1 can low fat sports shake with no more than 25 grams of protein, 1 sports bar, 1 banana, and water.  Two to three hours before the race, the kcal count drops to 300-400 kcal. Taking out the banana in previous examples drops the kcal to this amount, another example would be a smoothie with berries, banana, and 1 scoop soy or whey protein. One hour or less before the competition, only consume 100 kcal, as too much more will cause gastric upset with exercise. Fresh fruit, ½ bagel, or sports drinks are good examples.  White toast and regular pasta are recommended for a reason - having fiber before an event often causes stomach upset/cramping/diarrhea with the event. Endurance events also require carbohydrates with a higher glycemic index.    Whole grains are recommended in the days and weeks before the, but not the day of. 

Carbohydrate feeding during the event delays fatigue and ensures you will have the proper energy stores to finish the race. Carbohydrate feeding during an event also ensures you will maintain proper blood glucose and enhance performance.  From a physiological standpoint, the type of carbohydrate does not matter. Some athletes prefer a sports drink, while others prefer to eat a solid or gel and consume water. The rate of carbohydrate ingestion during an event should be approximately 26-30 g every 30 minutes, which is equivalent to 1 cup of a 6-8% carbohydrate solution taken every 15- 20 minutes. Less than 5% carbohydrate solution does not help performance, and over 10% can cause abdominal cramps, diarrhea, and nausea.

After the race, at least 20 hours will be needed for complete restoration of glycogen stores.  It is best to start carbohydrate intake immediately after exercise and at 15-60 minute intervals afterward for up to five hours after exercise. At this time, carbohydrates that are higher on the glycemic index are best as they will replenish glycogen stores better post exercise than low glycemic index. Adding 5-9 grams of protein with every 100 g of carbohydrate eaten helps increase glycogen synthesis rate and helps with muscle repair.  Many athletes find it difficult to eat immediately post exercise, so you may want to drink your carbohydrates or consider foods such as fruit pops, bananas, oranges, melons, or apple slices, or a smoothie with whey protein. Make sure to experiment with this during training so that when it comes to race day, you have found the right combination of foods that work best for you to optimize your performance.