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Eating your way to a successful marathon

By Christina Rogers, RD, CD, CDE – Registered Dietitian, Certified Dietitian, Certified Diabetes Educator

In a society full of opinions and studies regarding what, when and how to eat, it becomes harder and harder to separate fact from fiction. To get you on the right path, let's get back to the basics of food.

In addition to your running goals, marathon training should include the fine-tuning of your fuel sources. As your weekly mileage increases, it becomes more important for you to be consuming the right types of food. The following nutrition tips will guide you on how to eat to run your best!

Load up on carbs!

When talking with athletes, usually one of the first questions to be asked has to do with carbohydrates. With the prevalence of Atkins or "low-carb" diets, sport participants wonder what's the best way to eat to stay competitive and finish strong. Athletes simply need to eat a diet high in carbohydrates to keep their glycogen stores full. Doing this allows you to feel energized throughout the day instead of being tired all the time.

Glycogen stores are "silos" of sugar that provide energy to working muscles. When levels of stored glycogen (i.e., energy "silos") are low, your muscles do not work as well.

In addition to eating high carbohydrate meals, you should replenish your glycogen stores with a high carbohydrate snack after workouts to prevent fatigue. Glycogen stores are replenished faster and more efficiently right after and up to 30 - 60 minutes following exercise. Examples of high carbohydrate snacks include bagels, fruit, juice or a granola bar. Try to avoid a high fat diet. It can make you feel sluggish.

Quench that thirst!

Dehydration will prevent you from running at your potential. Thirst is not a good indicator of hydration. By the time you realize that you're thirsty, you've already started to become dehydrated. Drink before you are thirsty.

For everyday life, a good indicator of whether you are drinking enough fluids is going to the bathroom every 2-3 hours and excreting clear urine. And, while it's important to be drinking lots of fluids, be careful not to drink excessive amounts.

Water is sufficient for runs lasting less than an hour. For longer runs, like a marathon, sports drinks should be used in addition to water to replace diminishing electrolytes. Electrolytes, such as potassium, sodium and chloride, are minerals in our body that have specific, important functions. An imbalance of electrolytes can have fatal consequences!

Knowing that long, strenuous activities can deplete electrolytes, we need to find ways to replenish these minerals. The easiest way to add electrolytes is through sports drinks. Juices and soda contain electrolytes as well, however, their higher sugar content can cause cramping.

The following guidelines can be used to make sure you are consuming enough fluids.


  • 16-24 oz. fluids 2-3 hours prior to exercise
  • 4-8 oz. as possible 5-10 minutes prior to exercise
  • 6-12 oz. every 15-20 minutes during exercise (Beverages such as Gatorade, Powerade or Propel are recommended for events longer than 1 hour.)
  • Consume enough fluids after exercise to make urine pale – generally 12-24 oz. within 30 minutes.

Write it down:

Keeping a logbook that includes your food and fluid intake, as well as your running log, can help you track your progress. Make notes on how your runs feel, then look back and see what you ate and drank that day. Did you eat an adequate amount of carbohydrates at lunch before your afternoon run? Did you drink enough fluids?

You'll start to notice that with healthier eating habits your runs will feel so much better and on race day, you'll be reaching the finish line before you know it!

For more information about this or other sports medicine topics, call the Aurora Sports Medicine Hotline™ at 414-219-7776 or 800-219-7776.