Carbo Loading: Tips For Endurance Runners
by Nancy Clark, MS, RD

Oklahoma Runner & Triathlete
November/December 2006 issue

Does carbo-loading mean stuffing myself with pasta? Should I avoid protein the day before the marathon? Will carbo-loading make me fat...?

If you are a marathoner who is fearful of "hitting the wall," listen up: proper fueling before your marathon, triathlon or other competitive endurance event can make the difference between agony and ecstacy! If you plan to compete for longer than 90 minutes, you want to maximize the amount of glycogen stored in your muscles because poorly fueled muscles are associated with needless fatigue. The more glycogen, the more endurance (potentially). While the typical runner has about 80 to 120 mmol glycogen/kg muscle, a carbo-loaded runner can have about 200 mmol. This is enough to improve endurance by about 2 to 3%, to say nothing of make the race more enjoyable. While carbo-loading sounds simple (just stuff yourself with pasta, right?), the truth is many marathoners make food mistakes that hurt their performance. The last thing you want after having trained for months is to ruin your performance with poor nutrition, so carbo-load correctly!

Training Tactics

The biggest change in your schedule during the week before your marathon should be in your training, not in your food. Don't be tempted to do any last-minute long runs! You need to taper your training so that your muscles have adequate time to become fully fueled (and healed). Allow at least two easy or rest days pre-event.

Fueling Tactics

You need not eat hundreds more calories the week pre- marathon. You simply need to exercise less. This way, the 600 to 1,000 calories you generally expend during training can be used to fuel your muscles. All during this week, you should maintain your tried-and-true high-carbohydrate training diet. Drastic changes can easily lead to upset stomachs, diarrhea, or constipation. For example, carbo-loading on an unusually high amount of fruits and juices might cause diarrhea. Too many white flour, low fiber bagels, breads, and pasta might clog your system. As Marathon King Bill Rodgers once said "More marathons are won or lost in the porta-toilets than they are at the marathon..." Fuel wisely, not like a chow hound. Be sure that you carbo-load, not fat-load. Some runners eat gobs of butter on a dinner roll, big dollops of sour cream on a potato, and enough dressing to drown a salad. These fatty foods fill both the stomach and fat cells but leave muscles poorly fueled. The better bet is to trade the fats for extra carbohydrates. That is: instead of devouring one roll with butter for 200 calories, have two plain rolls for 200 calories. Enjoy pasta with tomato sauce rather than oil or cheese toppings. Choose low-fat frozen yogurt, not gourmet ice cream.

Meal Timing

NYC Marathon Queen Grete Waitz once said she never ate a very big meal the night before a marathon, as it usually would give her trouble the next day. She preferred to eat a bigger lunch. You, too, might find that pattern works well for your intestinal tract. That is, instead of relying upon a huge pasta dinner the night before your event, you might want to enjoy a substantial carb-fest at breakfast or lunch. This earlier meal allows plenty of time for the food to move through your system. You can also carbo-load two days before if you will be too nervous to eat much the day before the event. (The glycogen stays in your muscles until you exercise.) Then graze on crackers, chicken noodle soup, and other easily tolerated foods the day before the marathon. You'll be better off eating a little bit too much than too little the day before, but don't overstuff yourself. Learning the right balance takes practice. Hence, each long training run leading up to the endurance event offers the opportunity to learn which food--and how much of it--to eat. I repeat: During training, be sure to practice your pre-marathon carbo-loading meal so you'll have no surprises on race day!

Weight Gain

Runners who have properly carbo-loaded should gain about one to three pounds--but don't panic! This weight gain is good; it reflects water weight and indicates you have done a good job of fueling your muscles. For every ounce of carb stored in your body, you store almost three ounces water.

Fluids

Be sure to drink extra water, juices, and even soda pop, if desired. Abstain from too much wine, beer, and alcoholic beverages; they are not only poor sources of carbs, but can also hinder your ability to perform at your best. Drink enough alcohol-free beverages to produce a significant volume of urine every two to four hours. The urine should be pale yellow, like lemonade. Don't bother to overhydrate; your body is like a sponge and can absorb just so much fluid.

Protein

Many marathoners eat only carbs and totally avoid protein-rich foods the days before their event. Bad idea. Your body needs protein on a daily basis. Hence, you can and should eat a small serving of low-fat protein--such as poached eggs, yogurt, turkey, or chicken--as the accompaniment to most meals (not the main focus), or plant proteins such as beans and lentils (as tolerated).

Event day:

Carb-loading is just part of the fueling plan! What you eat on marathon day is critically important and helps to spare your limited muscle glycogen stores. By fueling yourself wisely both before and during the event, you can enjoy miles of smiles.