I've been trying my hand with Lean Gains-style intermittent fasting (16 hours fasting, 8 hours fed), and I'm going to be going on a day-long hiking trip in about a month. Considering I'll be doing a pretty aggressive hike (Old Rag in Virginia), is it still okay to continue fasting during the morning portion of my hike, then have a huge lunch?
I would ask Martin Berkhan himself, but he seems preoccupied answering redundant questions on his blog most of the time.
I've done it many times with no problems. If you can currently handle 16+ hours then you should be fine doing it in the wild.
One example was a hike along the Langdale Pikes (Lake District, England) which included a scramble up Jack's Rake. Beautiful country (not my site). Ate some summer sausage and coconut cream late in the afternoon then had a big dinner with meat and some taters.
Isn't this what some of our ancestors would have done in a hunt while waiting for an animal to tire out?
Drink lots of water as always, but possibly more since you won't be ingesting it from food.
If you are concerned, have your last meal earlier on the night before your hike. I only do this if I plan to time lunch with others or might happen into a pub.
I save the huge meal for dinner.
I find it easier to fast while hiking than when at work. The movement must shut my appetite up.
I would give it a try, your body is used to it, but bring something portable and easy to eat like jerky, pemmican, nuts/dried fruit or (gasp!) a protein bar just in case you find you need something immediately while you are hiking. Be absolutely sure to by adequately hydrated too.
In short, adapt by practing it pre hike, it's quite easy to become fat adapted in a month. Eat low carb, even ketosis for quicker adaptation so you don't suffer the low energy or headaches during the hike. Once you can comfortably skip 24 hrs of food, you should be fine for steady state hiking.
Hey Sean - nice piece by Gym Jones - Must checkout what MV02 is, particularly the training of you body to burn fat and spare muscle etc by eating good quality fat.
I do a 2 week unsupprted hike each May eg the Highlands 2009 and the Cambrian Way last year. Against conventional wisdom I make Jerky from fatty grass fed beef as on the trail I seem to prefer fat to lean meat - Might try pemmican this year on the Cape Wrath. Re the OP Asangsterrii IT will be no problem at all on any hike once you bed in. I lost 16 lbs on both hike (6ft 13st 6lbs starting) I never felt hungry and had to almost force myself to eat. I was burning fat but strongly suggest you get 1 big meal in a day. My longest fast last year was 25 hours. Too much when you are carrying 20lbs and climbing. Good luck