What to Eat Before a Marathon
We spoke with Dr. Rick Sharp, professor of exercise physiology, Department of Health and Human Performance, Iowa State University, to find out what you need to know to prepare to run a marathon. He told us “just as you need to insure your car has enough fuel before you start a trip, you need to “fuel” your body properly to enable it to last through a whole marathon.” We store “fuel” glucose, in the form of glycogen (GLY ko GIN) in our bodies. The glycogen gets converted to glucose when we need energy.
Dr. Sharp reinforced the importance of eating a high-carbohydrate diet while in training. According to standard practice recommendations, 60% of calories should come from carbohydrates, with complex carbohydrates and whole-grain foods being key to help build up your glycogen stores.
Getting enough fluid is also essential. During training, you can monitor fluid losses by weighing yourself before and after your workout. The difference in weight is your fluid loss. Replace 1½ times whatever is lost with water and foods containing water. For example, if you lost one pound (16 ounces) during the workout, replace it with three cups (24 ounces) of water. People don’t often realize that foods such as soup, fruit and vegetables, which are very high in water content, are great choices to help meet your fluid needs.
Dr. Sharp outlined the following pre-race eating plan:
Three days before the race, begin carbo-loading by eating even more carbohydrates (such as pasta, whole-grain breads, rice) to help insure your glycogen stores are full. Right before the race, Dr. Sharp suggests, “Top off your carbohydrate tank to last the whole marathon,” by eating a carbo-laden meal such as a large bowl of pasta. Additionally, consuming foods like chicken noodle soup about 45 minutes before the race will help your body delay dehydration.
During the race, drink fluids that have a mixture of sodium, potassium and carbohydrates. Drink 4-6 ounces every 15-20 minutes. Replace sweat losses early in the race. However, while fluid intake during the marathon is very important, you can have too much of a good thing. Excessive fluid consumption can be detrimental. Limit yourself to less than one liter of fluids every hour.
One note: During the marathon, you should only consume foods and beverages you’ve tried during training. The marathon is not the place to try something new. You want to insure that your body is comfortable with what you are eating and drinking.
And with that, good luck!