Most runners know they should eat pasta, rice, potatoes, or other high-carb foods before a half or full marathon. After all, carbs are a great source of energy, and you need a lot of energy to cover 13.1 or 26.2 miles. But many runners are far less clear on how many carbohydrates they should eat and when to start loading up. (Search: What are nutrition requirements for runners?) "When I go to marathon expos," says Monique Ryan, RD, author of Sports Nutrition for Endurance Athletes, "I'm amazed how many people haven't carbo-loaded properly. Runners train so hard and then arrive with a huge handicap." Here's what every runner needs to know about carbohydrates, so you can toe the line fully fueled and ready to go.
Recipes from Runner-Chefs
Carb Science
When you eat a bowl of spaghetti, most of the carbs are stored as glycogen in your muscles and liver. Glycogen is your body's most easily accessible form of energy, but it's not the only source, says Ryan. During a half or full marathon you burn both glycogen and fat. But the latter is not as efficient, which means your body has to work harder to convert it into fuel.
When you run out of glycogen during a race you hit "the wall." Your body has to slow down as it turns fat into energy. Benjamin Rapoport, a 2:55 marathoner, is intimately acquainted with the wall. The Harvard MD student (who has a PhD in electrical engineering from MIT) hit the wall so hard at the 2005 New York City Marathon he decided to study how to avoid it in the future (his research was published in PLoS Computational Biology in October 2010). "Proper carbo-loading—or filling your muscles to the brim with glycogen—won't make you faster, but it will allow you to run your best and, if you race smartly, avoid the wall," he says.
Smart Mid-Race Fueling Options
