Companion forum thread to:

A Case Study of Unsupported, Roadless, Long Distance Trekking: Part 1. Pack Weight, Distance, and Caloric Balance

There is one problem that puzzles me when I read some of the numbers concerning weight loss and caloric use during extended backpacking adventures. I have asked a few people over the years (and also experienced it myself) that I have lost 8-10 pounds during a three week backpack BUT upon returning to civilization I can put back 5-6 pounds in less than a week.
I do know that for at least one day I do "eat like a pig" but I have also suffered the "eyes bigger than the stomach" syndrome.

To gain 5 pounds in a week is something like BMR (basal metabolic rate) + 2500-3000 calories extra a day...........doesn't sound quite right.

I think that there is one underlying factor that people are leaving out of the equations.......electrolytes (salts). I teach that most Americans eat as much as 10X the salt needed in our normal diets. If a person cuts back on the salt while increasing exercise the body will find itself resetting homeostasis levels lower with less water. I always tell students that one of the first things addressed in diets is to reduce salt intake and what happens................?

Don Wilson wrote that he lost 4-5 pounds during his summer on the PCT but gained it back in a few days.

I would love to see a more precise measurement of body fat using water submergence since scales (even the Tanita) ones cannot give a precise measurement.

Randy

> I teach that most Americans eat as much as 10X the salt needed in our normal diets. If a person cuts back on the salt while increasing exercise the body will find itself resetting homeostasis levels lower with less water.
I will mildly disagree with you on fine detail. Not 'as much as 10x', but 'at least 10x'.

My wife and I take about 1 teaspoon of salt for a weeks walking. And we do NOT take highly processed foods.

Right on!

When you backpack (with ot without wife) do you see any appreciable change in your body weight or are you able to mimic dietary requirements on and off the trail?

I ask because many years ago I raced bicycles and when the season ended (at that time july) I would go backpacking. The problem was that with body fat at 5-7% I found it difficult to stay warm at night since my resting BMR dropped very low.

There is an interesting problem about efficeincy to be posed here.

Is it better to start a backpack in optimum shape (high VO2 and lean body mass) and to carry a heavier back so as to not lose muscle mass or to start the trip "heavier" of body and lighter of pack?

Randy

>> Is it better to start a backpack in optimum shape (high VO2 and lean body mass) and to carry a heavier back so as to not lose muscle mass or to start the trip "heavier" of body and lighter of pack?

Randy -

I can't answer the question of "is it better" in the context of the Arctic trek, but can offer a comparison of two scenarios, for this trek:

1. Start out weighing 165 and carrying a 60 pound pack with 50 lb food for ~600 miles and plan to lose 15 lbs.

or

2. Start out weighing 150 (lean weight) and carrying the remainder of calories (which note: probably can't all be fat cals) as a minimum of 15 lb of food, so starting pack weight of 75 lbs.

I don't think we could have done 20+ mile days early in the trek with pack weights this heavy, and the heavier packs would have increased body stress a bit. There's a bigger difference between 75 lb and 60 lb than there is, say, between 40 lb and 25 lb, in terms of that weight's ability to tax your body, IMO.

The heavier pack would have certainly increased the "time" required to hike 600 miles, and on a trek like this one, "time" is "ticking" as your body slowly degrades, unlike the case of a long distance thru-hike, where you have opportunities for regular rest, resupply, and calorie consumption at town stops or caches.

Edited by ryan on 12/20/2006 11:01:19 MST.

As I was reading I was wondering if the hamburger that Roman ate would be noted or if that would be played off. My commendation for keeping the trek as much within the realm of a scienctific experiment as possible.

Just some clarification re my PCT weight loss comments:

1. My hike was nowhere near unsupported, so is in a completely different category from the trek Ryan describes. I ate as much as I could stand while in towns, and I carried a lot of food with me on the trail. I didn't keep accurate measurements of food weight while on the trail, but I am sure I carried much more than Ryan, Jason and Roman, when measured in pounds per day.

2. My weight recovery comment is based on measurements I took when I got off the trail - but these were on different scales, so it could be off a bit. As anyone can testify who has hiked for many weeks - you eat a lot when you get off the trail and weight recovery can be amazingly quick.

"Arctic trekkers have bad dreams, too. It’s just that in all of their nightmares, the windowless rooms are carpeted in tussocks..."

I bet in some of the nightmares, Ryan, Roman, and Jason were being chased by a mosquito swarm of biblical proportions across the tussocks.


Happy Holidays!

Edited by pcmodem on 12/20/2006 13:56:38 MST.

Randy,
My experience on trips lasting from 10-17 days parallels yours. Weight loss of 6-9# and rapid gain afterward about equal yours. Doesn't sound right if you consider all the gain to be muscle/fat. My hypothesis is that a fair percentage of the gain is water, because I always lose about half of it several weeks later. Why water? In my case, I think it has to do with the fact that the 3 things I crave ASAP upon reaching trailhead are salt, fat, and lots of sweet liquid(OJ, Pepsi, whatever). The salt would likely result in water retention, IMHO. Also, there's a lot tissue breakdown to repair and water is vital to that process, isn't it? As for lean going in/heavy pack vs a few pounds of body fat/lighter pack, I've tried it both ways. I, too, used to race(distance running) and initially hit the trail at about 5% body fat and a heavier pack. On trips of 10-17 days, especially on the longer end, I used to come back having lost anywhere from 6-10 pounds, none of which I could afford. Felt lousy, metallic breath, lethargic, much longer recovery. Finally shifted to gaining weight,5-7# in a month of low activity before hitting the trail with a lighter pack, carrying 1 1/4 # of food/day with a calorie content of ~2800. I still lost about the same amount of weight, but came back almost even instead of 6-10 # in the hole, having lost maybe 2 # beyond the fat I packed on. Felt better and recovered faster. Just one person's experience. As for electrolytes, I, personally, can't do without them-I get leg cramps. Ended up using WHO oral rehydration salts at half strength on the strenuous days and miso soup at night. End of cramps.

A question I'd like to throw out is: which type of fat is more efficiently utilized by the body when exercising at a level where fat is the main substrate being catabolized, dietary or stored? Why? This seems like a contributing factor to consider when deciding whether to go with lean body/heavy pack or heavy body/light pack.

From an aerobic fitness point of view the better fitness that you have makes it easier to burn stored fat versus an less trained individual.

The point to raising ones aerobic level is to spare glycogen until you need it. The lower the intensity the more fat that is metabolized vs glycogen vs anaerobic respiration where you burn the high levels of glycogen.

The problem boils down to how well you can get to the fat. In trained individuals the fat can be stored within the muscle (intramuscular) whereas for most others it is stored subcutaneously in layers without a dense network of capillaries (white fat vs brown fat). I have seen athletes that by a pinch test show levels under 3% but actually have more fat but it is integrated in the muscle itself.

In dietary fats the components of the fat (glycerol and fatty acids) are absorbed into the lacteals (lymphatic vessels) then shunted off to the liver to be repackaged if in excess or they can be circulated in the body to the muscles.

In the end I would postulate that given two individuals with an equivalent amount of calories (body fat and carried calories) that a more highly trained individual with less body fat will be able to hike further than a less trained person with a lighter pack just based upon the efficiency of the motor itself. A more highly trained individual is capable of metabolizing a higher fat diet by being able to capture more oxygen for respiratory purposes.

Randy

This whole topic has got me rethinking and thinking for the first time about food.

So ... I went to NASA to see what the astronauts do about food. At least minimally here is what they post on the Internet, not that much IMO. (Not to poke fun at NASA, and especially the astronauts, have you ever heard of a brownie in its natural condition? -- I know they mean without rehydration but it sounded funny, now we know what we pay all the money for, sending unrehydrated and 'natural' brownies into outter space.)

It does seem BPL staff and trekkers might have the edge in some areas of figuring out food issues, maybe a big grant is in order for BPL to figure out how to get a UL tent and cooking system on the moon?:

http://spaceflight.nasa.gov/living/spacefood/

Edited by bdavis on 12/20/2006 22:56:59 MST.

Hi Randy

> When you backpack (with ot without wife) do you see any appreciable change in your body weight or are you able to mimic dietary requirements on and off the trail?
ALWAYS with wife. So info is for both of us.

Well, every couple of years we go mad and go walking for about 6 - 8 weeks straight. Last couple of times were in the Pyrenees in Europe. Before that either in UK or here in Oz. That is with pack and tent and SB.

Now walking in Europe is hardly 'unsupported' as we were able to buy food every 3 - 6 days in little villages along the Pyrenees. (Great fun.) So we ate what we wanted and bought what we needed for the next few days each time. (An unrestricted diet of fresh French bread and Brie cheese has its merits ...) I don't think we were calorie-restricted.

Each of us lost 6 - 8 lbs while walking. About half of this might have been excess body fat, while the other half was water. At home we know we are 'water-fat' to quote the Dune stories. That goes. Hum - I should add that in mild to warm weather we each use a TOTAL of under 3 litres of water per day - all drinking and all cooking. That seems to be a lot less than many others use. It goes with the minimal salt intake.

> The problem was that with body fat at 5-7% I found it difficult to stay warm at night since my resting BMR dropped very low.
Frankly, I do NOT think fat levels or BMR are relevant here. I think you should have had more dinner. OK, that is a very biased opinion, but a full tummy (lots of carbo) is a very good way to stay warm overnight in my experience.

My own purely personal opinion is that one can spend far too much time worrying about one's exact body weight, VO2 and fat levels. Stay fit and enjoy the walking. And before you get too excited about the fine details of body weight, go read 'Mind over Matter' by Ranulph Fiennes. It's about an unsupported crossing of the Antarctic. Will power has something to do with it.

>>"My own purely personal opinion is that one can spend far too much time worrying about one's exact body weight, VO2 and fat levels. Stay fit and enjoy the walking."

Roger, my sentiments exactly.

Many of these issues are only really important for ELITE ATHELETES and those PUSHING/exploring their own personal LIMITS. For the rest of us, who are out to enjoy ourselves or even challenge ourselves somewhat, it's probably majoring in the minors.

I can also understand why a Thru-Hiker, even one NOT going after some record, would also be somewhat concerned. However, and i'm just guessing here, that getting the problem 85%-90% solved is sufficient in most of these cases. After all, thousands of individuals have Thru-Hiked long trails over the decades w/o paying attention to "cutting-edge" nutritional and physiological science - even people in their 60's or 70's. How did they ever do it w/o the benefit of modern science (and gear)?!!! Your comments on mental toughness are well taken at this point.

IMHO, It's only the World Class Athelete, or someone of lesser caliber who is trying to achieve their personal maximum, that needs to be concerned with dotting every "i" and crossing every "t".

No one should take these comments as disparing them if they wish to understand and apply sciene to achieve their own personal goals. If that's your thing, go for it - good for you and best wishes for much success.

Tom, the body will use up dietary fat before utilizing stored fat. The efficiency of fat as a fuel is the same whether dietary or stored.

John,
I didn't express myself clearly enough. I was thinking more in terms of what it takes to get at the fat, i.e. energy expended to digest food containing dietary fat vs an enzyme cleaving fatty acid chains off a triglyceride molecule. Disregarding for the moment the energy it took to synthesize the triglyceride molecules at home while putting on weight, what is overall most efficient, energy-wise, on the trail, which is where it really counts?
PJ, Roger, et al,
For some of us pushing our limits is part of the enjoyment.
It's one major reason people race, at least at the "less than world class level". For me, personally, competition became secondary after a while and racing against the clock to see just how fast I could go on various types of terrain, in various weather conditions, was the primary motivating factor. And, I found I enjoyed the iterative process immensely. Sort of the kinetic equivalent of a gearhead, I guess. Or maybe a software writer, back in the old days when memory and CPU cycles mattered, iteratively polishing some arcane sub-routine to optimize memory and CPU usage. As for backpacking, the clock doesn't matter, but optimizing gear AND food in an attempt ease the strain on the body, be able to stay out longer, and go further/higher does very much matter to me, not to mention knowing I have enough in reserve to put the petal to the metal in an emergency. Bottom line, we spend a lot of time in these forums discussing ways to shave grams off our base weight, but relatively little trying to shave grams off the food we carry. Last time I looked, a gram of food weighs the same as a gram of gear and if, by a combination of training and careful balancing of food content and pace, we can shave grams(ounces? pounds?) off our total load, I would suggest it's an area well worth exploring.

Hear ya' Tom. Agree with you totally.

20-30yrs ago the burden of higher testosterone levels drove me similarly. [Note: The mention of the "t word" is NOT meant in a negative manner.]

Now, i just like to take it a little easier, and give it 9/10ths (as is said in auto racing - 9/10ths is when one has the race in hand, or their position locked up with no hope of improving, and is trying to avoid an equipment failure caused by pushing the car by giving it 10/10ths, and also 9/10ths helps to avoid a "brain"-fade mistake caused by pushing that will take one out of the race).

Edited by pj on 12/21/2006 13:18:07 MST.

Tom-Very well said! "...Bottom line, we spend a lot of time in these forums discussing ways to shave grams off our base weight, but relatively little trying to shave grams off the food we carry..."

I suspect that, in addition to the issue of complexity, psychological factors are in play relative to the equipment weight versus food weight (EvF#) paradox.

Are there any psychologists, professional or amateur (smile), that have an explanation for the EvF# paradox?

Edited by richard295 on 12/21/2006 14:21:18 MST.

is there more opportunity for wt savings w/gear?

i mean when one is down to 1.5lb food/day, w/o going to an all olive oil + supplements diet how much room for wt savings is there? not sure myself as i haven't run the numbers.

besides, "enjoyment" is part of the equation. i can enjoy myself more by cutting gear wt even with a few concessions on comfort, but will i enjoy myself if i hate my food (e.g., drinking an all olive oil diet on for 3+ days)?

the issue is not so much shaving grams off our food as it is maximizing calories for the grams of food that we carry, while still receiving proper nutrition.

lastly, i automagically SHAVE WEIGHT off of my food wt EACH DAY on the trail, by EATING it. my gear i must carry throughout the entire trek. perhaps this last point best explains the EvF# paradox???

[Note: i hope this last point doesn't start yet another "edible gear" series of Posts!!]

Edited by pj on 12/21/2006 15:35:11 MST.

Paul-The answer for experienced folks like you is, no. For someone just starting out in BPL, the answer is, yes. There are diminishing returns as you continue to shave gear weight.

The objective should be to select foods that you enjoy and most efficiently fuel the objectives of each trip segment. Let me illustrate this point by citing two examples.

When Ryan J. packed for the Artic 1000, he carried a plastic jar of peanut butter. That was a food choice that was both enjoyable to him and would most efficiently fuel the objectives of that trip. Carrying carbohydrate based sports drinks in place of the peanut butter would have been largely wasted weight.

When Al S. made his JMT attempt he utilized a lot of carbohydrate based sports drinks. That was a food choice that was both enjoyable to him and would most efficiently fuel the objectives of that trip. Carrying a jar of peanut butter in place of sport drinks powder would have been largely wasted weight.