Fuel for a Marathon

If you are planning to run the marathon this November, you are putting in a lot more time than just the day of the marathon itself. The training involved in planning for this exciting event is a huge investment of time and energy. So when the day comes you want to make sure you are well prepared and guaranteed to do your best. Along with the rigorous training that is needed, adequate nutrition is essential. If you are not eating the right foods, your muscles may not be properly fueled. As a result, your body may not be working at its full potential, which can lead to fatigue, dehydration, or low blood sugar during the marathon. This is sometimes called "hitting the wall".

An essential component to your training program should involve experimenting with different types of foods and drinks to learn what works best for you. We are all individuals and therefore have different preferences and digestive systems. For example, some runners cannot tolerate solid foods within 3 hours prior to running, while others find that their performance is improved when they eat a carbohydrate-rich snack 1.5 hours before a training. The important thing is to learn what foods you best tolerate, when to eat them, and how much to eat. With this knowledge you will have piece of mind that you are well prepared.

The three major goals of proper nutrition during endurance sports are (1) making sure your muscles are adequately fueled, (2) preventing dehydration and (3) preventing low blood sugar (hypoglycemia). Carbohydrate is the preferred fuel source during long distance running and is stored in the muscles in limited amounts as glycogen. You will need to train your muscles to store carbohydrate in order to ensure that they are adequately fueled. The goal is to saturate the muscles with glycogen to provide them with enough energy to last through the entire marathon. Therefore, a carbohydrate-rich diet, also known as "carb loading", is the key to ensuring that you are nutritionally prepared for the big day.

Carbohydrates include simple sugars and starches (long chains of sugars that are linked together). The major sources of carbs are rice, pasta, bread, potato, dried beans, fruits, vegetables, milk, and yogurt. These foods should make up at least 50% of your meals for the weeks to come. You guessed it…this is definitely not the time to start the Atkins Diet!

Carb loading means getting 55% to 65% of your daily calories from carbohydrate food sources. For a person who needs 2200 calories per day, they would need to eat 330 grams of carbohydrates per day to obtain 60% of their calories as carbs. To make it easier, this can be broken down into meal patterns:

Breakfast: 85 grams
Lunch: 85 grams
Snack: 30 grams
Dinner: 85 grams
Snack: 30 grams

See the attached sample meal plan for more details.

Carb loading can be like heaven for the carbohydrate lover. However, it is important to choose the right type of carbs. This can be done using the Glycemic Index (GI), which refers to the impact a food has on blood sugar response. Low GI foods tend to stabilize the blood sugar over a longer period of time, whereas higher GI foods cause a quick rise in blood sugar followed by a fast drop in blood sugar. This can lead to hypoglycemia in individuals who are sensitive to blood sugar swings. Your energy levels will be much lower if you feast on foods with a high glycemic index such as doughnuts and cookies as opposed to whole grains, fruits, and vegetables, which have a much lower glycemic index. Keep in mind that not everyone will be sensitive to the glycemic index of foods. It is also important to note that multiple factors can affect the GI of a specific food, such as meal size, combinations of foods, and food preparation. Therefore it is helpful to experiment with this during training. Please see the table below for examples of high and low GI foods. Additional information can be found at www.glycemicindex.com

Low GI	Medium GI	High GI
All Bran Cereal Carrots Beans Apples Oranges Pasta Barley Smoothie drink Bread (wheat/rye/pumpernickel) Yogurt Banana Milk chocolate	Couscous Cantaloupe Pineapple Sucrose (table sugar) Pasta Oats Raisins Rice (white or brown) Popcorn Sweet potato	Cheerios Cornflakes Shredded wheat Baked potato Muffins Plain bagel Waffle Pretzels

Proper hydration is essential to running the marathon. If you become even slightly dehydrated during the race, it will be near impossible to replenish while running. Dehydration can easily be prevented once you learn how much fluid your body needs. You will know you are well hydrated when your urine is pale yellow in color. If you are dehydrated, you will urinate less often and your urine will be much darker in color with a strong odor. You may also experience symptoms such as muscle cramps, nausea, headache, dizziness, and reduced performance.

So how much do you need to drink to keep you going? The average person needs about 8 cups (64 oz water) daily. However, endurance sports cause a loss of fluids through sweating that need to be replaced. You can figure out how much water to replace by weighing yourself before and after exercise. For every pound (16 oz) lost, you will need to replace 16 oz (2 cups) of fluid. The goal is to lose no more than 2% of your body weight during activity (the equivalent of 3 lbs for a 150 lb person). Drinking during exercise is important in preventing dehydration. Do not wait until you get thirsty to drink something, as this is a sign that you are already dehydrated. If you do, it will be almost impossible to catch up. Your best bet is to drink 8 ounces (1 cup or 8 gulps) of fluid every 15 to 20 minutes while exercising. During the marathon that means hitting just about every water station. It is especially important not to skip the earlier stations in order to prevent dehydration early on.

Okay, now you know how much to drink. The next question is what to drink. Water is more than enough for exercise sessions lasting less than 60 to 90 minutes. After that you will need to add some carbohydrate (to prevent low blood sugar) and sodium (to replace electrolytes lost though perspiration). You can do this with a sports drink (such as Gatorade or PowerAde) or water plus food that contains carbohydrate and sodium (such as pretzels or saltines). Most people prefer sports drinks to prevent stomach distress. The time to experiment is during the training period, not the day of the marathon. The general rule is to replenish with 0.5 grams carbohydrate per pound of body weight per hour of running. For example, a 150 lb person running for three hours would need to consume 75 grams of carbs per hour. Seventy-five grams would be the equivalent of the following options:

(1) Energy gel + 32 oz (4 cups) of sports drink (2) 45 oz (5.5 cups) of sports drink (3) 32 oz (4 cups) of sports drink + 1 small banana (4) Sports Bar (45 grams of carbs) + 16 oz (2 cups) of sports drink

Your training should include experimenting with meals and drinks before and during your long runs. Be prepared for the big day. Your pre-run meal should be well tolerated, easily digested, and high in carbohydrate. It will be helpful if you start your long runs at the same time you will be staring the marathon. Some runners tend to skip breakfast before a long run because they are afraid of getting indigestion. Digestion rate varies with individuals, but remember that the bigger the meal, the longer it will take to digest. Avoid eating high fat meals before running because fat slows down digestion. A large meal will take a good 3 to 4 hours to digest. If you prefer to eat closer to the time of your run, you may want to eat a small breakfast earlier and then a carbohydrate snack 1 to 2 hours before. Blenderized foods will digest more quickly, so this may be the route for some. The key is to find what works for you.

One week before the marathon:

The biggest change during this time will be in your training. You should be tapering off your training to allow your muscles to be fueled. If you train too hard this week, you will be burning off carbohydrate rather than saturating the muscles with glycogen. Contrary to popular belief, eating more calories than you normally do is not necessary during this time. Continue to eat meals and snacks that are high in carbohydrate.

The Day Before the Marathon:

Don't panic if you have gained a few pounds by now! Most of this is water retention. This happens because you are eating and storing lots of carbs. When you store carbohydrate, you are also storing a lot of water. This is a good sign that your muscles are saturated and ready. Make sure all of your meals are high in carbohydrate today. Drink enough fluids, but limit alcoholic beverages as they have a dehydrating effect.

Marathon Morning:

Eat the breakfast that worked best for you during your training period and be sure to allow enough time for digestion. Some runners wake up at 4 am to eat and then go back to sleep. Drink 2 to 3 cups (16 to 24 oz) of fluids about 1 to 2 hours before the race starts. Remember it takes 45 to 90 minutes for water to pass though your system, so you will have time to urinate before the race. Then drink again 5 to 15 minutes before the marathon begins.

Being prepared for the big day requires knowledge and practice. Now is the time to take the information you have learned through articles, books, and other experienced runners and apply it to your training. Do keep in mind that we are all a little different, so it is essential to learn what works best for you. Being prepared brings piece of mind. With this you can focus more and enjoy the day!