Carbo-Loading Before a Marathon

Spaghetti in Bowl
Spaghetti. Adam Gault/OJO Images/Getty

Will eating more carbohydrates the day before the marathon help your endurance, or is carbo-loading just a myth? 

Most serious marathoners have dropped the tactic of carbohydrate loading, according to the expert physician panel at the 2005 Marathon Directors College. Instead, you should eat a normal diet with 60 percent to 70 percent carbohydrates the week before the marathon, but do not increase your total calories.

The Old Carbo-Loading Theory

The older regimen had endurance athletes go on a low carb diet for three days, followed by a 70 percent carb diet for three days. This supposedly increased the glycogen in the muscles. However, it was found that eating a moderate 50 percent carb diet followed by three days of a 70 percent carb diet increased the glycogen just as much. And simply staying on a 50 percent carb diet all week still increased the glycogen, although not as much. There was no performance difference between any of these groups.

Dangers of the Pre-Race Pasta Party

If you have been eating a balanced diet the week before the marathon, you have already loaded your muscles with glycogen and you don't need to carbo load. The worst thing you can do for your marathon comfort is to load up huge plates of pasta and salad and high-fat salad dressing the night before the marathon. As one expert on the Marathon Director panel commented, "Constipation is unknown among marathon participants." What goes in is going to be coming out. You don't want the extra weight in your digestive tract the next morning, it's going to get a lot of jostling around. You don't want any roughage, such as from the salad. You don't want the extra weight, period. Eat a light, balanced meal to help prevent runner's trots during the marathon.

How to Eat the Week Before the Marathon

As you taper your activity in the week before the marathon, you should eat a balanced diet with 60-70% carbohydrates and not either overeat or eat too little. If you have been on a weight loss diet, increase your calories to match your basal metabolic rate. For women, this will be 1800 to 2000 calories per day.

What to Eat Two Days Before the Marathon

If you want a traditional pasta party, the time to do it is two nights before the marathon. Do not overeat. Reduce caffeine and alcohol consumption. Drink plenty of water. A giant bowl of pasta and a huge salad with lots of roughage is not recommended—you need moderation.

One Day Before the Marathon

Eliminate any high fiber foods and foods that cause gas, such as beans, broccoli, bran cereals, etc. If you are lactose intolerant, eliminate milk products. If spicy foods speed up your gut, eliminate them. Stick with low-residue foods and eat only enough to satisfy your basal metabolism. A dish such as low-carb coq au vin would be good. Eliminate alcohol and reduce caffeine to the bare minimum.

What to Eat the Morning of the Marathon

Many marathoners can't eat anything before the starting gun. Whatever you choose for breakfast should be bland and high in carbohydrates and easy to digest. If you must have some coffee, have as little as possible. Drink a large glass of water one to two hours before the start and have nothing more to drink until the starting gun. This will start you off well-hydrated, but it gives you enough time to eliminate any extra fluid. Just give yourself enough time to line up at the portable toilets before the starting gun.

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