Fueling for 50k to 100k

Updated: Jul 26

Dear Chaskis,

How do you fuel when racing and training ultras? How much should I be drinking during the race? Do you eat junk food? Please help!


Many a curious ultra runner

I love food and I care about my performance and I meet tons of runners in the same boat. How do I eat “healthy” as an athlete running 150 miles per week? How much protein, carbohydrate, and fat should I be consuming? What’s the best food to fuel my body when I’m running for 6+ hours? Do I have to give up ice cream?

Real Ultras

After I published my last installment in this nutrition series (Fueling for 50K), I got a lot of comments from readers who told me that, to them, my recommendations made more sense in the context of a marathon than an ultra race. From a time perspective, I was writing about a fueling for a race that would last less than three hours.

So, by popular demand, this is my take on fueling for races of 5-10 hours or 50km-100km.

Ty before his first 6+ hour effort to set the Inca Trail FKT in August, 2019

Day-to-day Fueling

If you’re going to run a 6+ hour race, you’re a pretty serious runner in my book. So, you already know that your training is going to require a different level of nutritional support than if you were just brunching without the long-run on Sundays.

That said, I don’t like to prescribe rules about calories or macronutrients because, just like with training, I know that everyone is an individual and it’s practically impossible to actually track your caloric expenditure and intake with any level of accuracy.

Luckily, we have a solution for that.

Trust the Body

The simplest way to figure out how much to eat, as well as what to eat, is simply to listen to your body. Our bodies are pretty good at telling us how hungry we are and what we’re craving—salty vs. sweet, protein vs. carbs, etc. As long as you aren’t eating super calorically dense food (where your body might not be able to realize how many calories you’ve consumed before you finish that pint of Ben & Jerry’s), if you simply eat until you’re full, you’ll be good to go. Pro-tip: if you’re having trouble with this, just eat slower. Sometimes the body just needs a minute to catch-up.

Don’t Stress about Body Image

Ultra-runners come in all shapes and sizes, even at the elite level. There’s a reason that the winners of UTMB don’t look like the winners of the Boston Marathon. Ultra racing prioritizes different strengths than road racing and your ability to withstand hours and hours of pounding and process calories while running is way more important than whether your body fat percentage is 6%.

Full disclosure—I’ve personally had issues with eating disorders and my relationship with food. If you’re running to lose weight, I’d recommend you make sure that’s backed by a desire to be healthy and has been OK’d by a doctor. Be careful, and if you’re struggling with negative thoughts about your body, don’t be afraid to reach out to family and friends or medical professionals.

Eat the “Healthy Stuff” First

If you want one real practical tip, here it is. Yes, when I’m in a big block of training, running 20+ miles per day for weeks on end, I’ve been known to have a large bowl of ice cream every night after dinner. But, even then, I try to fuel my body with “healthy food” before that.

What exactly is the "healthy stuff"? I think a general rule is things that come from the Earth vs. a package. Fruits, vegetables, fish, chicken, lean-meats, and carbohydrate-rich foods like rice, potatoes, sweet potato, or sourdough. If I’m still hungry and craving after I eat a reasonable amount of the good stuff, I have no qualms with reaching for the Phish Food.

[Editor's note: I have no promotional connection w/ Ben & Jerry’s. But seriously, totally open to that sponsorship. Hit me up.]