Nutrition, Hydration, and Energy Snacks for the Marathon

How to Eat and Drink Right During Training and on Marathon Race Day

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Getting nutrition, fluids and energy snacks right during marathon training and on race day is essential to making it to the finish line. Let's look at the diet you should be using during the weeks of training and how to eat and drink right on your long training walks as well as race day.

With your increased mileage during your training, you will be burning more calories and need proper nutrition to build muscles and capillaries to nourish those muscles.

Will You Lose Weight During Marathon Training?

Do not go on any extreme, unbalanced diets during your marathon training. However, now is a good time for those who are overweight to start on a balanced, mildly calorie-restricted diet, or to maintain their present balanced diet with no increase in calories or portions.

In both cases, walkers should see a slow and steady loss of fat and conversion of it to healthy muscle, bone, and lean tissue.

In 18 weeks of marathon training, you could lose 15 pounds of excess fat just from the training mileage—if you do not increase the amount you are eating and maintain the weight you were at when you started training.

For those who are within a few pounds of their ideal weight, listen to your body's cues as you increase your training distance. If you discover yourself losing weight and feeling worn out and tired, you should think of increasing your portions of a balanced diet or adding balanced snacks to your daily routine.

Carbohydrates Are an Endurance Athlete's Friend

The body needs available carbohydrate to burn on your long distance walking days. Low carb/high protein diets are not recommended for distance athletes. On your long distance training days, you may become dehydrated, which stresses the kidneys. Those on a high protein diet are already stressing their kidneys with the byproducts of breaking down protein for energy. Stick with the traditional balanced diet of 15 to 20 percent protein, 30 percent fat, and 50 to 55 percent carbohydrate.

Eat a variety of foods to ensure you get the micronutrients that can't be packaged in a pill. Try new vegetables and fruits. If you are restricting your calories, take a simple multivitamin each day to guard against deficiencies.

Do not start popping supplements. Most of the extra vitamins pass out in your urine, and again you don't want to stress your kidneys. Excess fat-soluble vitamins and some minerals are stored in the body and can build up to toxic levels.

You do not need any supplements that promise to build muscle. Endurance sports use long, lean muscles, not bulk. You are not looking for explosive strength, but muscles that can perform steadily for hours.

Carbo-Loading Before the Race

Carbo-loading before the marathon is the practice of eating higher-carbohydrate meals such as pasta in the three days before the marathon. The carb content can be 60 to 70 percent of your total calories. This brings the glycogen level in your tissues to its maximum so you have more available during the marathon. You don't have to overdo it, however. Eat normal portions and don't introduce any new foods. A previously-used technique was to deplete your stored carbohydrates first, but this has not been borne out by research.

Limit your alcohol and caffeine during the week before the marathon. You may also want to restrict high fiber or gassy foods in the day before the marathon, sticking with low-residue foods so you won't have runner's trots during the race. If you are lactose intolerant, eliminate milk products.

Don't Change Your Diet Right Before the Marathon

Most importantly, do not change your diet significantly in the week before the marathon. Practice good eating habits in the prior months and increase your favorite complex carbohydrate the three days before the event.

Energy Snacks for Your Long Training Days and Marathon Race Day

You will need to replenish energy to make it through a long training day of 10 miles or more. This is a good opportunity to see which energy snacks you tolerate best. It's also smart to research what will be provided on the marathon course and to train with those.

Marathon walkers have an advantage over runners—their bodies are able to replenish their energy from food and drink during the marathon. Most marathon walkers discover that they need to eat while on the course. The body burns off all available fuel and turns to burning whatever else is available. To stay in the race, simple carbohydrate is needed.

Types of Marathon Energy Snacks

Walkers going at a moderate pace may be able to snack on fruit, nuts, trail mix, or solid energy bars. But those who are moving at a pace that leaves them breathing hard realize that chewing can lead to choking, which is why many faster walkers and runners have come to use energy gels such as Gu or PowerGel. Samples of these are often given away before the race. Here are the common choices:

  • Fruit: Banana, orange or apple slices, and dried fruit such as raisins are all natural, and sometimes fruit is offered on the marathon course. With many fruits you have to deal with disposing of the peel or core, and keep it from getting bruised while carrying it. Dried fruit and fruit leather pack well, but require water to wash them down.
  • Trail Mix: This is a classic hiking snack, and it packs well in small bags. You will need to be able to chew and have water to wash it down. Mix your own trail mix from the bulk food bins to get the combination you prefer at a lower price.
  • Energy Bars: You will only need 100 to 150 calories at a time, so look for mini-size bars or cut larger bars into smaller portions. Look for energy bar varieties that don't have a coating that will melt or are crumbly and messy to eat.
  • Gummy Bears and Electrolyte Chews: Simple gummy bears and other gel candies are easy to pack and suck on with minimal chewing. Clif Shot Bloks and similar energy chews provide electrolytes as well as sugar for energy. They are easy to chew while walking fast and don't need as much water to wash down.
  • Energy Gels: These are made for a quick squeeze of carbs that you can swallow while breathing hard. They need to be washed down with water.

Try All Snacks and Drinks on Your Long Training Walks

Find out what fueling snacks and sports drinks will be offered on the course by browsing the race website or emailing the race organizer. If they are giving out an energy gel on the course or at the expo, you will want to know in advance so you can try it out first on your long training days.

If you think you will want to use a snack or energy gel during a race, be sure to try it out on your longer training days. Otherwise, you may discover that it upsets your stomach during the race, which is a bad time to discover anything new. You will also find that most sugary snacks need to be washed down with plenty of water, so plan your water stops or the amount you carry accordingly.

The cardinal rule is "Nothing new on race day." Try all energy snack, drinks, and gels before race day so you know whether you can tolerate them.

What to Drink During Marathon Training and on Race Day

How's your urine? You have to keep drinking enough water during an endurance walk to keep your urine light yellow and flush exercise toxins out of your body.

On all of your training walks, as well as your long distance walks, you need to stay hydrated. Drink a large glass (16 ounces) of water an hour before going for a training walk. The excess water then gets passed before you start your walk. Every 15 minutes to half an hour during your walk, depending on the temperature and the amount you sweat, drink another cup of water. When you finish your walk, end with a big glass of water, and have some salty snacks to replace body salt lost through sweat.

If your urine is dark yellow after your long training walk, you haven't been drinking enough. If it is straw yellow you have been drinking the right amount.

Hyponatremia and Dehydration

Marathon medical directors and the ACSM Marathon Fluid Guidelines tell endurance walkers and runners to let their thirst determine when and how much to drink. More people are obedient to the drinking guidelines and so dehydration is becoming less common, while marathon directors have seen growing numbers of cases of hyponatremia—washing out of body salts by sweat and drinking plain water rather than electrolyte-containing sports drinks. Here are more tips on hydration:

  • Weigh Yourself Before and After a Long Walk: To tell whether you are drinking too much or too little water, weigh yourself immediately before and after your long walks. Gaining weight is a sign of drinking too much plain water. Adjust your drinking to switch more to sports drinks to replace salts, or eat salty pretzels on your walk and drink a bit less plain water. Losing weight is a sign of dehydration—you are not drinking enough. Use your long training walks to get this right.
  • Caffeine: Lay off of caffeine before your walks. Not only does it make you have to urinate more often, but it also removes too much water from your system. If you are a coffee addict, cut back before your walk and treat yourself after you have had a good 16 ounces of water after your walk. Do not use high-caffeine energy drinks during a long walk.
  • Carrying Water: Part of your walking gear should be a water carrier. Fill your water bottle and take it along to guarantee that you have enough water while walking. Many people don't drink enough out of water fountains along the way, which may even be turned off during winter. Walkers should carry a bottle during the marathon as well. You may need a drink between water stations or find that they have folded up or run out of water or cups. That can be a dangerous situation that you will want to avoid.
  • Sports Drinks: Sports drinks and electrolyte replacement drinks can be used after walking for more than an hour and sweating. These replace the salt lost by sweating and also are sweetened to give you a jolt of sugar—the energy you need during an endurance event.

Hydration During the Marathon

During a marathon, you will generally be offered water and an electrolyte-replacement sports drink such as Gatorade. Some events use electrolyte drinks that don't have sugars—you need to know that so you can have some energy snacks with you as you still need those carbs during the event. Know your event and how these are spaced, so you won't drink too little and be caught thirsty between stations, or too much and get into overload.

Do not drink anything new on the day of the marathon. During your workout walks, practice by drinking the same energy drink you know will be offered at the marathon. This way you will know if it tends to upset your stomach. It is also unwise to use high-caffeine energy drinks during a marathon. A high dose of caffeine can lead to dehydration.

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By Wendy Bumgardner
Wendy Bumgardner is a freelance writer covering walking and other health and fitness topics and has competed in more than 1,000 walking events.