Fueling Your Full Marathon: A Cautionary Tale & A Training Plan

Friday, July 13, 2018

Joe and Ashley had each run quite a few 5Ks, 10Ks and a couple half marathons with increasingly fast times when they decided to train for a full marathon. The pair embarked on a training plan over weeks and months to ramp up in a smart way: They practiced increasingly difficult speed workouts, and strategically extended their long runs to prepare for 26.2 miles. Neither Joe nor Ashley could have run a marathon on the first day of training, but over those months they built tremendous strength and endurance to complete the distance.

But disaster struck on race day: Joe ate a packet of carbohydrate gel early on in the race and swigged a cup of sports drink from an aid station around the 10-mile mark, but it wasn’t enough. Just before the 20-mile mark, Joe hit what runners refer to as “the wall.” His legs felt like they were made of lead. His run slowed to a jog, then a walk, then he plopped down on a curb for 10 minutes sipping sports drink as dizziness, exhaustion and despondent feelings washed over him. He walked in the last 10K.

Ashley, on the other hand, wore a fuel belt loaded with carbohydrate gels someone recommended to her at the expo where she picked up her bib. She began fueling early and often—something she’d never tried before—and around mile 16, she felt bloated and nauseated, with water swishing heavily in her gut with every step. She miserably slogged along for the last 10 miles unable to take another bite or sip, walking for long sections of her race and visiting the porta-potties every chance she had.

Joe and Ashley neglected a vital part of marathon training: They didn’t have a race day fueling plan.

To avoid a splat on the proverbial wall in a marathon, a typical runner needs somewhere between 30-60 grams of carbohydrate per hour, depending on his or her size and speed (larger runners pushing faster speed potentially require closer to 90 grams per hour).

Digestion on the run can be a tricky affair, which is why there’s an entire section of sports nutrition at Charm City Run, filled with products designed to be easy on the gut while providing immediate fuel:

  • Carbohydrate gels (like Gu, Hammer, Stinger, Huma, etc) contain between 20-25 grams of carbohydrate per packet
  • A 1-ounce package of jelly beans (like Sports Beans) has about 25 grams of carbohydrate per bag
  • 8 ounces of sports drink (like Gatorade or Tailwind reconstituted at full strength) has about 10-15 grams of carbohydrate.

fuel 4.JPG

If you’re considering eating whole food instead of specially formulated sports nutrition, consider this:

  • One large date contains 10-13 grams of carbohydrate
  • A medium-sized banana has about 25 grams of carbs
  • An ounce worth of pretzels (just about a 100-calorie pack) has around 20 grams of carbs.

In order to meet your needs solely with bananas, you’d need to carry a produce section with you. But the bigger issue is the longer you run, the less blood your body sends to your digestive system as oxygenated blood is diverted to your hardworking legs. This is good for your legs, but tough for digesting solid food. You may end up under-fueled and in serious GI distress in the final third of your race.

A smart fueling training plan looks like this:

  • Early in the season, visit the running nutrition section at Charm City Run and look for products that sound tasty. Check out the carb content, too, considering how many carbs you’ll need to consume per hour on race day
  • Caffeine can be performance enhancer, but if it doesn’t agree with you in your daily life, it probably won’t agree with you on the run. If you choose to consume caffeine on race day, practice with it in training, and alternate between caffeinated and non-caffeinated products
  • Always consume a gel or chewable carb supplement with plain water
  • Test out products one at a time on the run to see how you like them in terms of taste, fueling and how they impact your gut. If you try two different gels, or a gel and a drink and have GI distress, you won’t know whether the gel, the drink, or the combo caused the issue.
  • Once you’ve confirmed you like a product, then you may choose to test mixing it with other products to meet your race day needs. For example, to reach 50 grams per hour, you may try one gel + 12 ounces of sports drink over an hour; or one gel + a snacking on bag of jelly beans over an hour.
  • There’s no need to consume as much carbohydrate on your training runs as you will on race day, and in fact, by going out with less fuel during training, you will adapt to becoming a better fat burner, which is a good thing. However, choose one or two of your longer runs as a fueling dress rehearsal: Eat a simple carb-rich breakfast 2-3 hours before your run, take your first bite of fuel early in the run, and test your race day fueling strategy.

And this is important: If you have a bad experience with one product, don’t completely dismiss the entire sports nutrition section. There are a variety of sweeteners and textures in each gel, bite, bean and drink, so keep experimenting to find what works best for you.

About the Author: Lauren Shafer


Lauren is a certified Health Coach who helps busy Baltimoreans articulate their health + wellness goals, and make measurable, sustainable diet and lifestyle changes for lasting transformation. Though she would never be described as athletic in her youth, Lauren started running as an adult, begrudgingly at first, until she discovered she actually enjoyed it. A10-time marathoner, 4-time ultra-marathoner and Boston Marathon qualifier, you’ll frequently find Lauren running on roads and trails with her husband John and dog Osita.

To learn more about Lauren and her health coaching practice Live Full, visit www.live-full.com or join the conversation on Facebook or Instagram. Contact her directly at lauren@live-full.com.


Friday, July 13, 2018

Live.Give.Run. Blog

We hope that you find this blog to be a source of training tips, inspiration and community. Our goal is to create a place online for every runner to find the motivation they need to hit the pavement. If you’d like to be a guest contributor, please email us at lauren@charmcityrun.com.

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