Nutrition And How To Use It On A Run

Full disclosure: I’m not a sports nutritionist. I’m not a food scientist either. I’ve just run 17 marathons, 3 Olympic Trials, and a Pan-American Games among them. I have been fortunate enough to hear some of the world’s best sports nutritionists speak and I’m going off of my notes, knowledge, and experience. I hope this can help some of you in your upcoming endeavors.

A marathon is a long race. I shouldn’t be letting some guarded secret out of the bag when I say that. It’s the kind of race that requires caloric intake whether you’re elite or a fitness jogger. The makeup of those calories as well as your body’s familiarity with the source can be a determining factor in whether you spend half of your distance hunting the next port-o-potty or chasing your goals.

The human body can store about 2000 calories in the form of glycogen in the muscles; it has another 350 or so calories in the liver for essential functions to be maintained; the last reserve of calories comes from fat stored on your body.

Glycogen is the fastest source of calories, but it can only take you for about 2 hours. Fat is the most abundant source of caloric energy. When you’re just out for an easy run on a flat path, fat is providing over half of the energy you burn. If you change gears to run up a steep hill or run a faster pace, your energy system also changes pace, to glycogen.

Ideally, you should also be consuming fluids when exercising as well. Those can come with or without calories attached. Drinks like Tailwind, Skratch Labs, or Gatorade will provide calories AND hydration in one step. If you are one of the many people with a sensitive stomach that won’t allow that to comfortably stay down (or in from either end), try a calorie free or low-calorie option like SOS Hydrate, Nuun, or good old water. Just remember that non-caloric options will require those precious calories to come from another source.

Other sources of calorie-on-the-go that runners use include energy gels, chews, or bars. I even know a guy that used peanut butter M&Ms to power his way through the Leadville 50 miler last year (me).

The biggest thing is to practice your intake on training runs. Practice first on short runs at an easy pace. Start simple first. If you’re someone who knows you like Gatorade, go for it! Be aware though that your body will react differently when it is under the stress of running. I spent years with one fluid and my body began to reject it over time. This is one of the imperfect experimentations that makes running so fun and maddening all in one. Something may work great on an easy run and not be tolerable at all after an hour. Try new things. Have fun with it. Keep track of what you’ve tried and if it made you sick, sluggish, or otherwise unwell.

That’s my advice to help you fuel your best performances. Feel free to drop in and chat with us in the store as well for more specific advice. We ARE here to help. Good luck, everyone!


  • Endure Bites
  • Honey Stinger (Chews, Honey Waffle, Gels)
  • NUUN Hydration
  • GU (Engergy Gel, Stroopwafel)
  • Tailwind
  • Skratch Lab (Fruit drops, Hydration Mix)
  • V Fuel
  • Accelerade