Before/During/After – Hydration and Fueling

By Abby Forman, MS, RD

Running a marathon takes fuel and a lot of it.  When, what, how much? These are the questions to figure out now, before race day arrives.  No one enjoys bonking or hitting the wall on mile 20.  Here are some basic guides for building your marathon fueling strategy to start and finish strong.  

Before a race, DO NOT TRY ANYTHING NEW! Choose low fiber, higher glycemic foods (also called low-residue foods) to help limit GI distress.  This means moderate amounts of complex carbohydrates.   This means going for the white toast instead of the double fiber multigrain or the Brussel’s sprout hash. If your race is early in the morning, DO NOT SKIP BREAKFAST!!! You are waking up having already used some glycogen while you were sleeping.  For the best chance of finishing well, you need to top off the tank.  If you have 2-3 hours before a race, have a full meal with a good helping of carbohydrates and smaller amounts of protein and fat.  One example is spreading peanut butter and a banana between 2 waffles.  As time gets closer have more simple sugar carbohydrates like Gatorade, crackers, or fruit purees with very little protein or fat.  Protein and fat take longer to digest and can cause upset or other issues.  

During the race, 30-60g carb per hour is the recommendation depending on your current diet and biology/genetics.  12oz of Gatorade Original has 21g of carbohydrate in it. Try a few longer training runs with 30g per hour and see how you feel.  If you still feel like you are lagging but have put in the mileage, add a little more.  Increase by about 10g at a time till you find what works for you.  More is not necessarily better.  Packing more is not always convenient and some people have GI distress when carbohydrate concentrations are past their personal limits.  

Water, water, water…. gulp at every available water station or pack your own and sip about 6-12oz every 10-20min.  Choose a beverage with added electrolytes if you are a salty sweater and especially when running longer than 60-90min.  The primary chemicals lost in sweat are sodium, chloride, potassium, and calcium, but each person’s sweat chemistry is a little different.   Most sports drinks like Gatorade or PowerAde will do fine and will have the carbohydrates needed to keep your run going.  After all that is what they were designed for.  Watch out for brands that claim to be rehydrators, but don’t come with these top 4 sweat components.  You can also make your own sports drinks if you are so inclined.  Check out these other dietitian’s sport drink recipes:

Cucumber Lime Electrolyte Refresher, from the Organic Dietitian

Home Brew Sports Drink, from Holly Larson

You used energy and fluid during your workout, now it is time to put it back.  If you weigh yourself before and after a run, drink 16-24oz of water for every pound lost.  Have a recovery snack with about a 3:1 or 4:1 ratio of carbohydrate to protein.  Chocolate milk is often touted as the ideal refueler because of its 3:1 ratio, but almost any sources of the macronutrients will do.  A trail mix of nuts, whole grains and dried fruit works well without needing to be cold.  In 2-3 hours have your next meal as usual or another snack if your next meal is still a while away.  Continue the refueling process about every 2-3 hours for the rest of the day and you will be all set for your next run.  It takes practice, hard work, and dedication to run a race, but it also takes fuel!  Good luck out there and if you have individual questions, ask your sports dietitian.