Intermittent Fasting on 500 mile Hikes

[slowtraveler]

I've loved fasting twice a week but I'm I'm debating on letting fasting go during the 2-3 months it'll take to do my 500 mile hike.

I'll likely have a more pleasant time with moderate fat loss from the hiking already but if I fast, it'll shed so much fat during those distance hikes.

Does anyone have experience with any 10+hr days of exercise fasted?

[bryan]

Maybe experiment during those 2-3 months?

Haven't done such a long term thing myself. Or slow hiking for that matter.

For the week long bike rides, I let my body have it's way when at whatever restaurant or grocery store (which is not always the case, as the nearest anything may be another 20 miles down the road). Meal planning before bicycle tours has been mostly about water, ensuring I have energy bars, and a couple MREs just in case. It was also getting a rough idea of which days will be easy to find something to eat and which areas I really need to find something ahead of time. I've resorted to the MRE less than a handful of times (e.g. I'd rather eat the MRE and rest at camp than ride my bike any farther).

[Dragline]

I would not recommend it. You'll probably lose weight no matter what you eat. But see how it goes. You can always try it, then eat.

Your biggest issue may be making sure you have enough electrolytes, particularly if you are sweating. Too much water and not enough salt = headaches, weakness and nausea.

[tommytebco]

I wouldn't. I have hiked a month for the last 8 years. I don't fast at all (although, I probably east less because refrigerator snacks are out of reach and weight is EVIL). I lose around 15 to 20 pounds. That leaves me gaunt at the end.
gaunt is not healthy.

[BRUTE]

technically, "gaunt" from low-but-still-healthy body fat percentage is not problematic (where healthy bf% is defined as >5% for human males and >15% for human females). gaunt from muscle loss should be avoided pretty much all the time.

on another technical note, IF does not restrict average energy intake, only the timing. it is very feasible to eat 5,000kcal in one meal a day, brute has done it many times.

if the goal of IF is fat loss, that might be unnecessary during such intense exercise.

brute recommends simply trying what works well. if Felipe feels hungry, he can eat. if he can hike all day and only eat a big dinner, then that's fine. should body fat levels or performance drop suspiciously, he can always eat more. there's plenty margin of error, as these things rarely happen overnight.

+1 the electrolytes Dragline mentioned though, salt, potassium, and magnesium should probably be supplemented.

[slowtraveler]

Overall consensus is don't or experiment and take electrolytes.

So I'll feel it out for when to experiment and make 2 modifications to my fasts:
*Add a pinch of salt to my water.
*Take the complete multivitamin mix I already have to keep up nutrient levels throughout the day. It happens to include a small amount of protein so I'll end up 40-120 calories in the 24 hour period depending on how many scoops of multivitamin mix I have.

[Jean]

500 miles in 2 month is less than ten [s]months[/s] miles a day. I can walk 30 miles on a empty stomach without feeling bad at all.
I would definitely try to continue with your IF.

[bryan]

I can walk 30 miles on a empty stomach without feeling bad at all.

[IlliniDave]

Doesn't sound like a great idea to me, especially if the hike is covers remote, rugged terrain. And I don't know exactly what you mean by fasting. Just a suggestion, assuming you are talking about going 24 hours or more between meals when you say fasting, but I'd try getting the first 100-200 miles under my belt and see how that goes before trying to push the envelope.

I have experience with portage canoe trips in wilderness areas where I'd only eat a very light breakfast (piece of jerky and water) then not eat again on travel days until we reached our destination for the day and cooked the main grub for the day, which would meet many religious definitions of fasting. That was doable for me for 10-12 day trips, 3 days travel 1 day R&R, but towards the end it starts to add up. I can't imagine doing that for 60-90 days. Most of the travel was paddling which isn't bad until the hours add up, but the portages are rough/unimproved passages with heavy loads (though short, usually less than a mile). The risk of accumulated fatigue is mostly injury.

Of course if you're talking something along the lines of what BRUTE alluded too and just eat 3-4 meals-worth of food in one sitting a couple days week and normally the rest of the time you'll probably be okay if your guts can handle it.

[theanimal]

I think there are different definitions being used for fasting. The OP says 10+ hours. In that case go for it. I do IF normally with about a 6-8 he eating window each day. I've done a few multi day 100+ mi trip in AK from a few days to 2 months. I've found that my eating window increases to about 10 hours and I can maintain this hiking or paddling for 25+ miles off trail in rugged terrain.

I have also done fasting 24 hrs plus on back country trips with the longest being ~2 days. This I would strongly recommend against unless forced or you are masochistic like myself.

It also depends on what type of food you'll be eating. If you are eating lots of carbs/sugar you'll have a harder time lasting between meals. The more fat the better.

[IlliniDave]

I think there are different definitions being used for fasting. The OP says 10+ hours.

Yeah, if that's the case I misunderstood. I thought he meant 10 hours travel time per day with days of essentially skipping food thrown in a couple times a week (that's what IFers I know do--24 hours or longer w/o solid food). Ten hours between meals is not unusual for me, and 24 is closer to normal, though I've never done it throughout a 60-90 day hiking trip or anything of similar duration.

[theanimal]

ID- On second reading, it appears the misunderstanding is mine.

I'd also like to echo the comments about salt water balance. Being on the wrong side of that isn't much fun. Make sure to bring salty foods and/or extra salt.

[BRUTE]

the amount of salt needed per day by fasting humans is surprisingly high. the recommendation is about 4-6g of sodium per day for an adult. that's enough to make a glass of water undrinkably salty. a pinch might not be enough if it's the only source of salt (bc no food intake), especially if there is a lot of sweating.

[Jean]

I can walk 30 miles on a empty stomach without feeling bad at all.

That's easy, a few weeks on the warrior diet (only eating in the evening) made me able to do it, and I never losed this ability afterward even if I eat regularly 2 or 3 meals a day.
I never tried long term fasting.
But after two days with low salt dehydrated food, I get very strong headache, that only disapeared with salted peanuts. I repeated this patern a few times before understanding this.
So, fasting or not, watch your salt intake. Because you will lose a lot of salt while sweating.

[bryan]

I suppose it's less surprising if you prepare your body for it, as you say.

It's just so outside of my norm I was ed. Now would be a nice time to have a "life stats," data analytic program for insights, or something.

[slowtraveler]

"4-6g of sodium per day for an adult"
I'm not surprised even though this goes against hearing to eat less salt all my life for kidney stones. It explains my urges to binge on salt during fasts. It's surprising how much salt I'd add to water.

I'll try 5 grams per day and adjust from there. I'll also let myself have salt more liberally on my fasts. Didn't realize how good it was for those times. Typical salt is heavy in sodium chloride and low in magnesium, potassium, all the other electrolytes. Any recommendations for salt?

I'll be eating mostly salty snacky foods like homemade salted vegan peanut m&ms.

[Dragline]

Those sorts of things should work just fine. It's better to eat salty foods than just the salt itself, because its absorbed better.

[jennypenny]

Salt some fruit like cantaloupe or watermelon. It's a good combination nutrition-wise and provides some hydration as well.

[BRUTE]

sea salt or himalayan salt have more minerals

[7Wannabe5]

Several years ago, I fasted for Ramadan with my "ex" while doing a major renovation job in up to 90 degree F heat. So, I wasn't even drinking water until sundown while performing manual labor which might have been roughly equivalent to slow hike in hot situation. I have an early-riser sleep schedule, so there was a limit to how much I could eat in the evening before falling over hard asleep. I lost quite a bit of weight very rapidly (maybe 10 lbs. in 15 days), but didn't suffer any other serious ill effects or distressing symptoms.

My "ex" told me that the feeling of thirst in your mouth is just a warning signal which will come and go that is not indicative of true dehydration. I have never researched the truth of this statement, but it was my experience that the feeling of mouth thirst would occur at some point in the day, and then somewhat abate if ignored, rather than increase. However, the overall feeling of thirst definitely trumps the feeling of hunger, and it seems like the human body has quite a bit of potential to keep engaging in labor with neither water or food supplied during the course of a day. This makes sense to me since any ancient human who did not have water at hand might have needed to hike some distance to find water, or oh-so-delicious pomegranate juice.

So, your body will be losing/using water and salts as you hike, and if you drink X amount of pure water to replace impure water lost (without eating food naturally containing salts), you will also need to provide Y amount of salts to replace salts lost, or you will suffer some variety of osmotic effects. Quick search for information on the topic of true minimum human water intake needs yielded this site, which you may want to take with a grain of salt

http://www.watercures.org/survival-hydration.html

WARNING: Based on my experience, I definitely would NOT purposefully choose to limit water intake in a situation in which I wasn't 100% sure of provision of supply of water within 24 hour time frame.

This experience also led me to believe the theory that one of the primary causes of the obesity epidemic is the increase of intake of sugary liquids by the general population. There is a strict limit to how much sugar and salt you can comfortably ingest without increasing fluid intake, and the level of fluid retention in the body is engaged in systems feedback related to hormone production.