Become a Member

Get access to more than 30 brands, premium video, exclusive content, events, mapping, and more.

Already have an account? Sign In

Become a Member

Get access to more than 30 brands, premium video, exclusive content, events, mapping, and more.

Already have an account? Sign In

Brands

Race-Day Nutrition

How to Choose the Best Fuel for Long Runs and Races

A step-by-step guide to keep in mind when picking the right fuel for your next adventure.

Lock Icon

Join O+ to unlock this story.

Already have an Outside Account? Sign in

Outside+ Logo

All-Access
Intro Offer
$3.99 / month*

  • World-class journalism from publications like Outside, Ski, Trail Runner, Climbing, and Backpacker.
  • Annual print subscription to Outside Magazine + 2 Gear Guides.
  • Outside Watch – Award-winning adventure films, documentaries, and series.
  • Gaia GPS – Premium backcountry navigation app.
  • Trailforks – Discover trails around the globe.
  • Outside Learn – Expert-led online classes on climbing, cooking, skiing, fitness, and beyond.
Join Outside+
Trail Runner Magazine

Digital + Print
Intro Offer
$2.99 / month*

  • Access to all member-exclusive content on TrailRunnerMag.com
  • Ad-free access to TrailRunnerMag.com
Join Trail Runner


*Outside memberships are billed annually. Print subscriptions available to U.S. residents only. You may cancel your membership at anytime, but no refunds will be issued for payments already made. Upon cancellation, you will have access to your membership through the end of your paid year. More Details

Do a quick online search for sports nutrition products and you’ll get thousands of results. Unfortunately, with so many options, runners are left with a huge question mark as to what they should be eating and drinking to fuel long runs and races.  The short answer? It depends. There are numerous factors at play: the duration, the intensity, the climate you’ll be in, your sweat rate and your gut tolerance, to name a few. That’s why you’ll want to figure out your best, personalized plan well in advance of a goal event.

Here’s how to fuel for a long run or a trail race.

how to fuel long run trail race

Pre-run: Top Off the Tank 

Do you need to fuel every long run?

Before any activity over 60 minutes, it’s a good idea to top off your fuel tank, especially if it is a morning training session after a night of sleep.  This will allow for your glycogen stores to be full at the start to keep you going longer and more efficiently throughout your training session or race. 

When considering options that might work best for you, take into account the following guidelines:

Calories: 

  • For runs up to 3 hours: 300-500 calories
    • Examples: Bagel with peanut butter and a banana; two frozen waffles with syrup and a banana
  • For runs greater than 3 hours in duration: 500-700 calories
    • Examples: Bagel with peanut butter, banana, granola and honey; two frozen waffles with peanut butter, syrup and a banana

Carbohydrates:

Keep fiber to a minimum.  A good guideline is less than 5g total pre-run.  Most of your pre-run fuel should be composed of carbohydrates to reduce chances of gastrointestinal distress. Avoid multigrain products, brown rice, beans and berries if you have a sensitive stomach, as the seeds can be tougher for your digestive system to process.

Fats:

Fat tolerance can vary depending on the athlete, but in general because fats are digested much slower, use caution with the amount of fat you consume pre-run.  (5-10g is a good target).

Protein:  

Including some protein (8-15g) in your pre-run fuel can help slow the release of carbohydrates into the bloodstream.  This can decrease the chance of rebound hypoglycemia, the abrupt drop in blood sugar that leads to energy highs and lows once your carbohydrate stores are burned up.  Keep in mind, protein is digested slower, so too much can cause stomach problems.

RELATED: Five Nutrition Truths For Trail Runners

Timing:

Timing your pre-run meal depends on your tolerance. Giving yourself time to digest can help prevent cramping and allow your body to utilize the food that was taken in. It is always a good idea to practice with different options before making your final decision (like during long runs leading up to a goal race).

Once you start your run, it can be difficult to pinpoint the products that will work best.  When choosing your in-run fuel, keep the following in mind.

how to fuel an ultra trail run race long run

Choosing a Hydration Mix

Step #1: Consider whether you want to get calories and carbohydrates from your hydration mix.  Hydration mixes aren’t a requirement for fueling, but they can be a helpful option if you don’t want to take in as much fuel from gels, chews and food during your run.

RELATED: How much Electrolyte Do You Need?

Step #2: Check the sugar content. Read the ingredients list to see what is in the mix and note whether it contains glucose, fructose, maltodextrin, sucrose, etc.  Keep in mind, if you can tolerate fructose, it is ideal to vary the sugar types in your fueling plan.  

Step #3: Consider sodium content: Sodium is a key electrolyte, and you lose a lot of it through sweat.  It plays a crucial role in helping your body break down carbohydrates, so if you don’t get enough, you could end up with digestive issues.  A good target for sodium intake is 250-500 mg/hour, but that can vary depending on sweat rate, sweat composition and climate.

Choosing a Gel or Chew

Step #1: Consider the length and intensity of your run.  The higher the intensity, the more the blood will be diverted away from the digestive system.  In those cases, gels or chews that are higher in carbohydrates and lower in fat and protein will be easier to digest. If you are doing a longer effort or race (>3 hr in duration), incorporate some fat and protein.  

Step #2: Evaluate the sugar types, just like with drink mixes. Read the nutrition facts and look for sugar types such as fructose, glucose, maltodextrin, and sucrose.  If the gel is fruit based, it will automatically contain fructose.

RELATED: 4 Natural Energy Gel Alternatives

Step #3: Avoid sugar alcohols.  If any of your gels or nutrition products contain sugar alcohols, run far away. Sugar alcohols like maltitol and sorbitol can stimulate the digestive system (bad news).

Step #4: Consider the sodium content.  Remember, hydration mixes don’t have to be your only source of sodium.

Step #5: Caffeine. Caffeine can be helpful to use for a boost during longer efforts, but use caution. Its strong stimulation effect can impact your digestive system.  Wait until later in your run to take in caffeine when you need it most.

Put it All Together

If combining a hydration mix and gels and/or chews, you will need to evaluate the nutrition from all products together on a per hour intake basis.  Take caution with too much of a particular type of sugar (fructose or glucose), as well as too little or too much sodium, fat or protein.  Remember, nutrition can make or break your runs, but with some careful planning and considerations, you can set yourself up for success.