Fuel & Training Tips

How To Eat For Heat: Fueling For a Hot Ultra Marathon with Jeff Browning

How To Eat For Heat: Fueling For a Hot Ultra Marathon with Jeff Browning

We caught up with MUIR Athlete & ultra-running legend Jeff Browning before he toes the starting line at the iconic Western States 100 miler this month. 

Finishing the 2018 Western States. Photo: Paul Nelson
Finishing the 2018 Western States. Photo: Paul Nelson

Jeff Browning, also known as Bronco Billy, is an icon in the ultra-running world. He’s known for consistently placing well in races with fierce fields, finishing over 100 ultramarathons, his low-carb high-fat approach to nutrition, and his unique and recognizable style on the trail.

Jeff will be competing for the 6th time this year at Western States. With 5 finishes under his belt and placing in the top 10 in all but one of them, he’s more than familiar with the course – and the heat. Western States is a notoriously hot race, often exceeding temperatures over 100 degrees.

The race directors are well aware of the danger. In the ‘Medical Risks’ section of the WSER website, you’ll find the first three risks are all heat related: renal shutdown, heat stroke, and the dangers of low sodium.  

Luckily, Jeff is a proven and versatile mountain athlete even in the face of extreme temperatures. Part of his versatility and ability to perform so consistently is attributed to his dialed nutrition strategy. 

Scouting run on the Hardrock 100 course in 2018. Photo: Jeff Abbott
Scouting run, Hardrock 100, 2018. Photo: Jeff Abbott

We caught up with Jeff to talk about the race and how to fuel for a hot race like The Western States 100-mile Endurance Run (WSER):

MUIR: Thanks so much for catching up, Jeff. All of us at Muir are really excited for you to race Western this year. How is your training going? Are you getting excited for Western?

Jeff: Thank you! Training is going well and yes, I’m really looking forward to it.  


M: If you know a race is going to be hot, what factors do you change? 

J: Running in the heat makes it harder to take in as many calories as I normally would, so I have to change what kinds of calories I take in.

You lose a lot of sodium and water when it’s hot, too, so you have to take in water and salt.

I also start heat training* about three weeks from race day.

*Heat training is training your body to adapt to run more efficiently in high temperatures. Often, we slow down when the temperature increases, and health risks become more serious. Through gradually increasing intensity and temperature, it’s possible to train your body to run more efficiently in heat and help offset the heat-related health risks come race day.

Jeff Browning, 2018 Western StatesDuring the 2018 Western States. Photo: Paul Nelson 


M: How does the heat change what you eat during the run?

J: It’s difficult to consume as many calories in the heat, so I take in a lot more liquid calories. These are easier to digest when it’s hot out. 

My target is 150-200 calories per hour. 


M: What about hydration?

J: Usually I shoot for 1 liter/per hour to drink and ramp up to around 1.3 liters per hour when it’s hot. As for sodium, I take in 600-800mg per hour.  I’m a heavy sweater, so it’s really important for me to stay on top of my hydration and electrolytes. 


M: How do you take in sodium?

J: I get some through sports drinks – 1 bottle of electrolyte mix and 1 bottle of water. In mountain races, I’ll drink salty broth, and chug electrolytes at aid stations. 


M: What about salt capsules? Do you use those?

J: Yes they can be great, but it’s really important to look at the label. A lot of electrolyte caps have too much calcium and magnesium. Your body does a pretty good job at retaining calcium and magnesium when you exercise, but it dumps sodium and potassium. 

So, I always tell my athletes to look at the label and make sure the capsules have way more sodium and potassium than the other electrolytes.

I really like Succeed S-caps because they only have sodium and potassium.  


M: What happens when you’re not well hydrated?

J:  Dehydration is really hard on your kidneys. You’ll know you’re in the danger zone when you can’t pee. At Western, it’s a requirement before you can have the post-race beer. 


M: Have you ever experienced cramping during a race? How did you remedy it?

J: I’ve had minor cramping, but no melt-downs. Usually, cramping is related to sodium, so I just make sure to take in more salt. 


M: No major melt-downs? That’s really impressive! Any particular reason why, you think?

J: I grew up with heat and humidity in Missouri. I spent the summers baling hay and playing football in crazy heat and humidity. I’ve been used to the heat for a long time. 


MUIR: Thanks so much, Jeff! We will all be cheering you on at Western and again at the Hardrock 100 in a few weeks. 

2018 Western StatesPhoto: @broncobilly 

Jeff’s Fueling Strategy for Hot Races 




600-800 mg/Hr



Note: These targets are meant to be considered as a reference, not a prescription. Targets will differ for everyone, but this is a great point-of-reference.

Jeff’s Advice for Running in the Heat

  • Try to get more calories in liquid form than solid foods
  • Increase both hourly water and sodium intake 
  • Beware of increasing other electrolytes besides sodium and potassium too much
  • Incorporate heat training to help offset heat-related health risks for race day
Jeff Browning, 2018 Hardrock 100, Photo: Jacob HansonJeff during the 2018 Hardrock 100. Photo: Jacob Hanson

Jeff will be racing The Western States 100-mile Endurance Run on Friday, June 26th. You can follow along on his Instagram: @gobroncobilly

You can also find race updates on Instagram: @wser  

Jeff will be racing The Hardrock 100 just a few weeks later on July 11th. He is the latest champion, when the race last ran in 2018. Stay tuned.