As I live near Lake Tahoe at roughly 6200 feet, and frequently ride, ski, and hike in the mountains above, I'm already mostly acclimatized to altitude...though there isn't much air at 14,500' either way.

The Grand Canyon is a difficult hike because it's hot, almost entirely without shade, and you're going uphill for the trip back.  (All the mule poop doesn't help either.)

Do recall that endurance exercise -- particularly fasted endurance exercise -- is strongly catabolic: endurance athletes actually have higher protein requirements than strength athletes AFAIK.  So don't skimp on the meat.

Welcome!  I hope you'll stick around.

JS

That's solid work!  It's liberating to realize our bodies are perfectly capable of such feats...and scary to realize that most people today can't even comprehend the possibility.

Yes, diet is a big part of it...if you don't have metabolic flexibility, you'll never make it past the first few hours without an "energy bar".  And while I'm not VLC myself, it's a nearly foolproof way to force your body to re-learn how to oxidize fat for energy.

Most importantly, that's an astounding rebound from a diagnosis of autoimmune disease!  I'm glad to hear of your recovery.

JS

You will appreciate this.

I walked only a little over 23 miles today.

It was around 1400 ft elevation total.
23.3 miles.
I did almost 13 miles barefooted
I did not bring water or food and had none the entire time.
I did not eat breakfast either. I was 12-13 hours fasted when I started. All I had today was a glass of water and coffee before I started walking.
I wore no sun block
All I brought was my t-shirt, baseball cap, shorts, gps and shoes with no support and completely flat.

I walked over 8 hours and never once got hungry, thirsty, tired or unhappy.

All that stopped we was the soreness on the bottom of my feet (a little raw).

I plan on doing at least a marathon walk/hike like this every month.

I eat around 70-75% calories from fat normally. I only do 15 grams carbs max a day.

Oh I need to mention, last year I could not walk my psoriatic arthritis was so bad. Ever since going paleo, it has really solved/cured almost all my issues. Now is cleaning up my joint damage from years of inflammation.

My only cheats are raw grass fed sharp cheddar once a month or so. Raw grass fed heavy cream on a rare occasion and 85% dark chocolate coconut clusters I make at home.

I typically fast 18-22 hours between meals. Some days I go 26-36 hours and once a month I go 44-48 hours. And my meals are so fatty my friends have a hard time even looking at my plate. Sausages covered in butter and beef tallow. ETC...

Total time was just under 14 hours round-trip from the Whitney Portal trailhead, including about an hour on the summit and a lot of talking with other hikers.  I don't know how quickly I could have done it...but if speed had been my goal, I would have eaten something!

JS

Absolutely.  We spend most of our time in boxes.  That's not right.  When have you seen a box in nature?

JS

Thank you.  It means a lot to know I'm making a positive difference in others' lives.  And I'm glad you enjoyed The Gnoll Credo.  Isn't Gryka wonderful?  I still miss her.

JS

"That's some really interesting info from Twight: thank you! I'll have to look up the book."

The book is from 1999, and there isn't any real science in it. Just an incredible amount of experience, and very useful and detailed advice on how to train, eat and climb to return alive. (Plus lots of awesome photos and stories.) Twight sure knows how to treat the human body to get the utmost out of it.

"Alpinism is one of the few remaining pursuits where survival is completely in the hands of the participant."

Which is exactly why I love it so much.
My biggest pet peeve is that these days hardly anybody is willing to take responsibility for anything in their lives. Not for the bad things that happen (always gotta sue someone), not for their living or financial situation, not for their health or their happiness. It's always the circumstances or the genes or other people or something else.

Our society has developed accordingly, so these days most of the responsibility is taken out of people's hands anyway. Responsibility and freedom go hand in hand. Give up the first, lose the latter.
If we want 100% of the freedom we need to be willing to take on 100% of the responsibility. So I go where I'm allowed to do that.

Btw, I can't tell you how much I appreciate all the work that you and others do that makes it so much easier for us to take responsibility for our health.
Thank you!

Your experience is very similar to mine.  And you're right: people have been told for so long that "you need carbs for energy" that they think they'll simply sputter to a stop, like a car running out of gas, without an endless supply of sugary junk to suck on.

That's some really interesting info from Twight: thank you!  I'll have to look up the book.  And it's the sort of information almost no one knows anymore, because almost no one pushes the human body to its limits anymore except a few athletes under carefully controlled conditions, with ambulance ready and waiting.  Alpinism is one of the few remaining pursuits where survival is completely in the hands of the participant — there is often no possibility of rescue, let alone first aid — and the alternative to pushing your limits is to die.  Beck Weathers is an extreme example.

Thank you for sharing your experiences, and for helping to emphasize that this isn't a matter of being genetically gifted — it's just diet and training, mostly diet.  Did Paleolithic humans say "Hey, I'm hungry, I'd better go eat something so we can go hunt?"  No, they said, "I'm hungry, let's hunt down something to eat."

Welcome to gnolls.org: I hope you'll stick around.

JS

I ALWAYS climb fastet, because any food in my stomach diverts blood and energy away from my muscles. Performance invariably dips. I always feel my best and most energetic with an empty stomach. I dislike eating when I have to work hard and avoid it at all cost.

ALL my climbing partners have a high carb breakfast and consider it essential, and of course they have to continue all day topping up. Alpine climbs more often than not start some time between midnight and 3am, and usually some time after lunch the people around me start to falter and crumble, despite constantly gulping down energy drinks and carbohydrate gels and what not. I don't get tired, ever, I can go on and on and on, for as long as it takes.

I've even had arguments over it. People demand I eat because otherwise I would put them into danger as well when I hit the inevitable wall. It has never happened yet.
Haven't been able to convince people yet that I am not some genetic freak, but that it's normal and a function of what I eat, or rather, what I don't eat, and how I train.

Having said all that, the kind of climbing I do is not so extreme yet that I would have to dip into my glycogen stores often. Like you wrote, the key is to keep the intensity below the basal rate of fat oxidation. If I did empty my glycogen stores, I'd run into trouble because even fat oxidation requires some corbohydrate to be burned in the background. (Can't recall the exact details, just remember reading about all this in "Extreme Alpinism" by Mark Twight.)

Mark Twight also describes an interesting phenomenon that was new to me, hitting the wall when burning fat. Apparently in his experience, and also in that of other extreme climbers, there comes a point where the body seems to be unwilling to release any more fatty acids. And the cure is to have some fatty food. Even tossing back a shot glass of olive oil works. The moment the body knows more fat is coming (there isn't enough time to actually digest the fat), it's happy to release more from the stores.
He has no explanation for this, just recounted the experience and the fact that many climbers share it.

Fuelling 24-48 hours of intense effort in the mountains is an interesting challenge.
Eating for a day or two of sustained moderate effort on the other hand is easy. Don't 🙂