Edit. Looks like the article is slightly misleading. Ballinger used carbs around the ascent, and low carb while training
Strava Intel: On May 25, Ballinger ascended 2,395 feet over a distance of two miles, staying in a low heart rate zone. Adjust for altitude and the grade of Everest, and it was like he was running a 6:08 minute mile.
Inspirational.
“I’ve been completely dependent on carbohydrate for all of my climbing,” he says. “I was always hungry, morning to night, but I also had this line I would tell everyone, you know, ‘I never gain weight, my metabolism must be so high, I can eat a loaf of bread a day.’”
.
When you’re a carb-burner, you have about 45 minutes of fuel storage in your body — glycogen — at any one time, and after that your body runs out; you have to feed yourself constantly to keep it up. But while that system works fine on most peaks, in the punishing altitudes of Everest — above 25,000 feet is dubbed “the death zone” because of the lack of oxygen — suddenly your digestive system shuts down, you feel nauseous, and you can’t put food in your mouth, Ballinger says. When his hands went icy, it’s because he was depleted of glycogen; his body went into protective mode, and sent more blood flow to his gut and away from his extremities. “All of a sudden I didn’t have those carbs stored — I needed my body to burn fat for fuel.” But his body wasn’t primed to do it, Johnston guessed.
.
The lab, found out that his body shifted from burning fat for fuel to burning carbs when his heart rate hit 115 beats per minute.“So, pretty much if I’m doing anything above a walk, I’m burning carbohydrates,” In comparison, his climbing partner shifts from burning fat to carbs at 163 bpm.
.
The solution, was to become a fat-burner. In practice, that means Ballinger embraced a ketogenic diet, limiting the calories he eats from carbs to just 10 percent of his daily intake, and getting 60 percent from fats and 30 percent from protein
.
That meant Ballinger had to keep his heart rate under 135 bpm for some 80 percent of his 20 to 26 hours of weekly cardio. “I felt so slow,” he admits. “I couldn’t keep up with my friends in Tahoe because everyone charges all the time; I’d go for runs where I used to cover 12 miles, and suddenly I could only do seven miles in the same amount of time. ” But gradually, he says, he started to see the shift. “While still keeping my heart rate under 135, I could go faster and faster and faster.”
.
For the majority of his workouts, Ballinger would wake up and do slow, grueling endurance workouts for three and even up to seven hours without any food before or during. A day’s worth of exercise without even an energy bar might sound masochistic, but all of us (even 141-pound Ballinger) have close to 100,000 calories in fat stores readily available to burn, versus the mere 2,000 calories of stored calories from carbs, Johnston says. We just have to train ourselves to tap into them. The fasted workouts forced Ballinger’s metabolism to gradually shift to prefer fat for fuel, and things got easier.
.
“A few weeks into training, I started to feel entirely different — I could go for long workouts and not bonk, wake up in the morning and go for hours without eating,” he says. “I used to be the kind of person who would wake up and couldn’t send a text until I’d eaten some food. I was that short of energy.”
.
Most important, Ballinger’s fat-burning metabolism and revamped training approach proved that the hunger cravings he’d had on mountains before, the highs and lows based on constantly needing to eat or feeling fatigued, wasn’t the most efficient way to do what he wanted to do: climb 8,000-meter peaks, trail run, and ski. “This past ski season was the best I’ve ever had, and not only because the snow’s been amazing — I directly credit this,” he says. “It’s wild — I’d never thought about nutrition before.”
I’m so happy to see this. When I saw the news of this in media here in Norway, my initial thought was “He must be fat fueled” But I saw no such thing mentioned in media here. Woho 
Go KETO 