CARBO-LOAD UP, WASH IT DOWN… Preparing and Training… The substance behind a...DIET Jane E. Allen LA Times Staff Writer

MARATHONS, DIET, PHYSICAL FITNESS, RUNNING, NUTRITION

In the weeks before a marathon, a good nutrition plan is an important part of any training regimen. That means getting enough fluids and carbohydrates for training runs and the big day.

Before any long practice run, it's important to drink plenty of water, which helps regulate body temperature, bring nutrients to your muscles and cleanse the body. The tried-and-true practice of "carbo-loading" -- eating foods high in carbohydrates -- is a must for high-intensity exercise that lasts more than 90 minutes. Carbohydrates are broken down into glucose and stored as glycogen; the ability to store glycogen in your muscles determines your endurance.

Marathoners pushing hard for more than 90 minutes in practice runs and during the 26.2-mile race need to load up on carbs so their muscles can store extra glycogen to help them go the distance. Two hours before a practice run, drink 8 to 16 ounces of water or sports drinks. Also, have a light snack, such as a sports bar with roughly equal amounts of protein and carbohydrates to provide and sustain energy, says Rania Batayneh, a nutritionist at the Sports Club/LA in San Francisco.

During the run, drink a half-cup to one cup of water or sports drink every 15 to 20 minutes to replace lost salts. Within 15 minutes of completing the practice run, have a snack to replace depleted energy stores.

Tapering your activity in the week before the marathon helps your performance by allowing your body to store more glycogen, allowing you to run longer without fatigue.

Three days before the marathon, sports nutrition experts advise, begin carbo-loading at lunch and dinner to increase your glycogen stores. Choose high-carbohydrate foods such as pasta, rice, potatoes and cereals, making them 65% to 70% of each meal. Also include fruit, vegetables and lean proteins, such as chicken, fish, milk, yogurt or soy. Try to drink 64 ounces of water throughout the day, Batayneh advises.

The day before the marathon, go heavy on the carbohydrates. Stick with simple pastas with simple sauces (forget the high-fat cream sauces), and stay away from high-salt foods, which can dehydrate you, and high-fat foods, which can make you sluggish. Avoid eating salad or raw vegetables, which may cause digestive distress on race day. Drink plain water; avoid caffeine and alcohol that are dehydrating.

On marathon day, drink plenty of fluids up to 15 minutes before the race, and have a high-carbohydrate snack like a bagel or sports bar within that final half-hour to supply sugar to your brain. Drink half a cup to one cup of fluid every 15 to 20 minutes during the marathon.

"Nothing is more important to assuring a long-distance runner's success than hydration," Batayneh says.

About every 50 minutes, put some kind of easy-to-digest fuel in your system, such as liquid gels, bananas or energy bars.

Once you cross that finish line, drink something and grab a snack. To help your body recover and to restore depleted glycogen in your muscles, your next meal should emphasize carbohydrates, but make sure you're getting about 20% protein to help repair those sore muscles.