Carb-Loading: Two Approaches

Yesterday's post ("Breaking Through the Wall"), spurred some great comments and emails from readers wanting more information on carb-loading before a race. So, I did a little digging to widen my horizons on the topic. Here's what I found.

First of all (like I said in yesterday's post) carb-loading is all fine-and-dandy and does play a very important role in preparing you for race day, but you need to make sure your getting a steady stream of high-quality complex carbs all through your training. Always keep in the back of your mind that your body has a limit to the amount of glycogen (fuel) it can hold. It's not able to keep a huge reserve, so you need to keep replenishing the supply. The carb-goal for a runner should be to keep an optimal amount of carbs in the tank at all times.

Glycogen is a runner's fuel and carb-loading is how a runner tops-off his/her tank. A typical runner's "tank" provides enough fuel for about a 20-mile run. In my digging I discovered two different approaches to carb-loading. The first approach is more traditional and involves carb-loading over a week. The second approach is based on newer thinking and involves doing most of the carb-loading the day before the race in addtion to a very short but intense workout.

Traditional Approach: The Mayo Clinic recommends carb-loading in two phases

Phase 1: About 7 days prior to race day, your carbohydrate intake should be about 50 to 55 percent of your total calories. Continue training at your normal level to deplete your carbohydrate stores and make room for the carb-loading that takes place in Phase 2.

Phase 2: About 3-4 days before race day, increase your carbohydrate intake to 70 percent of your daily calories—or about 4.5 grams of carbohydrates per pound of body weight. Cut back on foods higher in fat to compensate for the extra carbohydrate-rich foods. Also scale back your training to avoid depleting your glycogen stores. Rest completely for a day before the event.

For a sample carb-loading meal plan from Stephen DeBoer, a marathon runner and registered dietitian at Mayo Clinic, Rochester, Minn. [click here].

New Approach: If you've tried the more traditional method of carb-loading and it didn't seem to work for you, you may want to give this method reported in the L.A. Examiner a try. It's based on a study by the University of Western Australia. I have not tried this method, so I can't speak first-hand of its results, but many runners swear by it. To read the actual L.A. Examiner article [click here].

Step 1: Eat lightly and normally the week before the marathon.
Step 2: The day before your marathon, do a 3 minute, very-high-intensity speed workout in the morning. (For the reporter who wrote the article, that meant running two-plus all-out laps at the track.)
Step 3: Consume 12 grams of carbs for every kilo of lean body mass spread over the next 24 hours. That's a HUGE amount of carbs. (The reporter who wrote the article is a runner who weighed 150lbs. To get in this amount of carbs, he drank four 18-ounce cans of ABB Carboforce . He said ten 12-ounce bottles of the new Gatorade Carbohydrate Energy Formula would work as well too.)

Keep in mind that carb-loading isn't the "end-all." You'll still need to replenish your carb stores during the race to maintain your blood sugar levels—this is when sports drink and gels are particularly effective.

Like most things, carb-loading can have its drawbacks and may not be right for every runner.

• Most runners will experience some temporary weight gain from carb-loading. Don't panic, much of this weight is extra water, but if the extra weight is so much that it affects your performance you may want to reconsider carb-loading on your next race or adjust the amount of carbs you ingest.
• Carb-loading can cause some runners to experience digestive discomfort. The Mayo Clinic suggests avoiding or limiting some high-fiber foods (beans, bran and broccoli) one or two days before the raced.
• Carb-loading can also affect your blood sugar levels. The Mayo Clinic suggests consulting with a doctor or a registered dietitian before starting carb-loading, especially if you have diabetes, and especially if it's your first experience with carb-loading.