–Originally posted March 2013–


Fueling for a 100-mile running race through the mountains is not only an enormous feat athletically, it poses great obstacles nutritionally.

Ultra runners typically race between 18 hours and 30+ hours in order to accomplish this feat and do so with little or no sleep at all. This means running through the night often at high altitude and through a wide range of temperatures.

The famed Western States Endurance Run from Squaw Valley to Auburn California climbs 18,000 feet before descending nearly 23,000 feet. Runners endure temperatures ranging from the high 40’s to over 100 degrees through the course of a single race. These enormous variances and distances pose issues physically, mentally and nutritionally.

Runners Face Unique Nutrition Requirements

It is well established that the act of running due to its jarring up and down movement reduces an athletes ability to absorb nutrients versus events like xc-skiing or cycling. Runners must also carry much of their nutrition and fluids between aid stations that at times can be hours apart.

Athletes have just two to three hours of glycogen stored in their muscles and liver.

It’s also well known that athletes have just two to three hours of glycogen stored in their muscles and liver.  Once this glycogen is used, athletes enter the dreaded bonk zone. There is no one perfect nutrition plan for ultra running, in fact our runners vary considerably in their nutrition plans, however there are some consistencies that can offer a greater chance of success when planning out your racing nutrition needs.

We have asked our eight elite ultra runners to map out their nutrition plans for 100 mile running races. Understand these are ultra runners with many years of experience, meaning their bodies have adapted to the rigors of running 100 miles.  They bring both experience and also a physiological adaptation that can only be developed over many, many seasons of running. Even for these elite runners it takes years before they finally nail their nutrition.

Duncan Callahan put it best “For many years, a poor fueling strategy significantly hindered my ultra-running performance.  I felt like a blind guy playing darts – bouncing from idea to idea and ‘wishing’ that something would work. Beginning in the fall of 2009, I went on a research quest to find a nutrition system and plan that would work for me.”   That year Duncan won the prestigious Leadville-100 on EFS electrolyte drinks.

Ultra Running Nutrition Plans

Below is a list of our elite ultra runners with some key attributes of their running nutrition plan.


Duncan Callahan
2X Leadville 100 mile champion
Detailed Nutrition Plan
-Large breakfast (1,400 calories) 2 hours before the race
-Sip on EFS leading up to race start
-240 to 360 calories/ hour
-Majority of calories from EFS
-If really hungry ‘warmed mashed sweet potatoes’


Krissy Moehl
Ultra Trail du Mont Blanc Champion
Detailed Nutrition Plan
-Same breakfast before every race: Oatmeal PB & J, 2 hours before the race
-EFS liquid shot every 30-45 minutes
-PreRace every 2-hours
-Nibble on Clif Bar or potatoes to feel satiated.


Luke Nelson
2nd Place 2012 Wasatch 100
Detailed Nutrition Plan
-Ultragen, Tortilla with Nutella 2 hours before the race
-Sip on EFS liquid shot with PreRace leading up to start
-300 calories per hour
-Sip on the Luke Nelson Slurry (1 scoop EFS, 1 EFS Liquid shot in a 10oz bottle topped off with water)
-Nutella and Jam wraps as solid food at aid stations
“The last 50 miles are the crux when it comes to fueling.  It is the most critical time to keep the calories flowing, but for me at least, my stomach isn’t too excited about anything.  I do well by keeping it simple and keep taking nips of the slurry.


Jacob Puzey
2017 50K Ultra Canadian Champion
Detailed Nutrition Plan
-Breakfast: Tube of  Trail Butter, Banana, Granola Bar + Water/EFS, Optygen (3)
-Sip EFS every 5-10 minutes.
-Nurse flask of EFS Liquid Shot every 15-30 minutes. 1 flask at least every 2 hours (200-400 calories).


Nick Clark
Wasatch 100 Champion
Detailed Nutrition Plan
-Breakfast of donuts, bagel and coffee 2 hours before the race
-Hydrate with EFS leading up to start
-10-30 ounces of EFS drink every hour and EFS liquid shot flask every three to four hours
When it’s cool I drink less total fluid and consume more EFS liquid shot.  When it gets hot I rely more on EFS drink.
-Mostly fruit at aid stations


Scott Jaime
50K USATF Masters Champion 3.13
Detailed Nutrition Plan
-In cool temps 20oz bottle with 200 calories EFS liquid shot
-In hot temps.  1st 20oz bottle with 200 calories EFS liquid shot and water  2nd 20oz bottle with 100 calories EFS grape.


Darcy Africa
1st Bighorn 100 CR
1st Hardrock 100
1st Bear 100 CR
Detailed Nutrition Plan
-200/300 calories per hour
-Don’t change up breakfast: oatmeal, banana, and coffee
-Always carry 1-bottle EFS and 1 bottle water during entire race
-Take OptygenHP after 50mile mark
-Carry EFS LS Kona Mocha, a bar and honey stinger chews


Karl Meltzer
34 – 100 Mile Ultra victories
Detailed Nutrition Plan
-250/350 calories per hour
-80% from EFS LS and 20% from EFS drink
-A few RedBull drinks, Honey Stinger
-Potato soup, Boullion and if hot SaltStick caps


Tips On Developing Your Running Nutrition Plan

Your pace determines what ratio of glycogen to fat you burn

The most overlooked element of nutrition for many runners is pace.   It is your pace that determines what ratio of glycogen to fat you burn.  As you approach anaerobic efforts or high HR efforts you begin to burn almost exclusively glycogen for which you only carry a 3-hour supply.   At moderate aerobic efforts you burn primarily fat, for which you have plenty to last days.

Run or walk aerobically all day and you should be able to keep up with your demand for glycogen.  Pacing usually fails on that first climb when everyone is together.  Stick to YOUR aerobic pace.  If you go anaerobic you immediately start burning your glycogen and can, very early on, initiate a bonk.  Remember that at altitude your heart rate will be elevated 10-20 beats higher, this means you have to slow the pace even further to get to your aerobic level.

-Breakfast 2 hours before (eat what you are accustomed to, though focus on carbohydrates and if possible gluten free carbohydrates).

-Pre-hydrate with an electrolyte fuel drink like EFS for the 24 hours leading up to the race.

-Consistent fueling, sipping drink every 5-10 minutes.  Don’t get behind.   Most athletes will need 250-350 calories per hour, though only you can determine your exact amount.   Wasatch 100 champion Nick Clark through years of adaptation prefers to run on minimal calories.  Meaning Nick has used this methodology in his training so he is more efficient at burning fat.  Its important athletes know what they can handle and choose an appropriate caloric intake goal.

-The majority of calories should come in liquid form.  This offers hydration and superior absorption.  Being hungry is OK.  This means your stomach is empty which means the fuel you are consuming is going to your muscles.  *First Endurance does endorse the concept of fueling an entire Ultra on liquid alone.  Few practice this, though the elite runners do tend to have fueling strategies that have far more liquids than solids. 

-Limit solid foods and spread out evenly in very small portions.  Solid foods can back up your system if you are not careful.  Consume them with adequate water.

-Solution percentage and electrolytes should change as temperature changes:  Hot temperatures mean you should consume a minimum of 12oz fluid for every 100 calories and a good dose of electrolytes like those found in EFSPRO.  In warm temps EFS works well.   In cold temperatures both electrolytes and fluids can be lower and you should therefore target approximately 100 calories with 6oz fluid.  EFS Liquid Shot is great for cold weather running.



-Have contingencies built in.

a) If stomach gets upset or sloshy, go to straight water, or nothing at all.

b) If ‘very hungry’ take small amount of solid food.  Do not have a big meal.

c) If cramping go to water and very salty snack (pickles) or sip on EFS or EFSPRO drink at an 7%-8% solution.

Remember that proper training will give you the fitness to get to the finish, but poor nutrition will prevent you from getting there.   Not only should your training plan be meticulous, so should your nutrition plan.

The first step is to have some semblance of a plan and practice it during your training.   You can choose different race nutrition segments to practice on different run occasions, i.e., pick three different breakfasts of varying nutrients and calories and see how you feel going on a long run two hours post breakfast.  Learn what works for breakfast,   then move on to determining what concentration you want your calories at varying temperatures.