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Shed Extra Pounds Quickly and Safely

Backpacking and Weight Loss

By Jim Wood

Published April 14, 2005
Last update: April 23, 2005

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As a longtime hiker and backpacker, I spend a fair amount of time poking around Internet discussion forums in order to stay abreast of new developments. When so doing, I'm often struck by the apparent obsession that many backpackers have with equipment, and especially with its weight. Part of this fixation is understandable, of course. Anyone who has carried an overloaded pack through a 12,000 foot mountain pass understands the need to trim gear weight wherever possible. But what also strikes me about these forums is that there's usually little or no discussion about body weight.

I suppose that like all backpackers, I need to be reminded occasionally that the heaviest component of the system is not my pack, tent, sleeping bag, nor even my food. It's me. Perhaps because body weight is a constant companion, it's easy to forget that when backpacking, it's the mass of the entire package that really matters and that the sum of our food, water and equipment actually represents a relatively small percentage of the total. If we consider, for example, a 180 pound man carrying a 35 pound load, it helps to maintain perspective by knowing that the pack weight is only about 16% of the aggregate burden that's got to be hauled up the mountain.

The world press never seems to grow weary of calling our collective attention to the fact that Westerners (and Americans in particular) are among the fattest humans on the planet and that obesity-related ills are threatening to overtake all other popular causes of premature death. I'm not aware of any published statistics on the matter, but I suspect that taken as a group, backpackers are probably in better shape than the average of the greater population. In fact, studies suggest that many of those who are serious students of the pursuit enjoy fitness levels that are comparable to top athletes in other disciplines. Nonetheless, my own observations confirm that there are still plenty of overweight backpackers wandering the trails.

Carrying an extra pound or two in one's pack can be a big deal for a lot of ultralighters. But if one is 20 pounds overweight, obsessing over that extra bit of gear while ignoring the body weight issue seems pretty silly to me. Even if a backpacker were given a choice between carrying 20 extra pounds of equipment and 20 extra pounds of fat, I suspect that few physicians, when viewing the proposition from a health point of view, would consider it to be an even trade.

I would therefore propose to anyone who backpacks and seeks to improve efficiency that unless you happen to already be at an optimal body weight (counts me out), you'd probably be best served by spending at least as much time focusing on reducing body weight as you do on reducing pack weight. The great news for overweight backpackers (or most others who might wish to shed pounds) is that backpacking itself probably ranks among very top ways to lose weight quickly and safely (assuming, of course, that one is fit enough to engage in the activity in the first place).

The Simple Math

There are several reasons for backpacking's weight loss advantages, but probably the most compelling is the simple math. Backpacking, especially in the mountains, is hard work. For many people, backpacking is, in fact, probably the most physically-demanding thing they will ever do, at least over an extended period of time. Depending on body and pack weight, terrain, physical conditioning, gender, miles walked, and many other factors, a backpacker can expend anywhere from 4,000 to 9,000 calories (or more) a day. For someone who is 20 pounds overweight, carries a 35 pound pack and spends 7 hours a day walking, the daily burn (including the effect of camp chores and similar activities) will be at the high end of the range, probably in the 7,000 to 8,000 calorie neighborhood (actual calculations are provided below).

Because nearly all backpackers today carry their entire food supplies with them (few attempt to "live off the land" anymore), the calories available to nourish this substantial daily expenditure are limited by the contents of their packs. The average food weight ported by most backpackers on a one or two-week trip is probably a little over 2 pounds a day, including packaging. This weight can vary a lot, of course, and depends again on a wide range of factors. Many hikers try to minimize pack weight by using mostly dehydrated, freeze-dried, and other foods that contain a minimum of water, the most significant of the "inert ingredients" that add weight, but no calories, to food. Those who use lots of fresh foods have higher daily weights.

There is a mathematical model, in fact, that backpackers will soon be able to use to forecast the total weight of the food necessary for any given trip. It's driven by variables such daily calorie targets, the desired mix of proteins, fats and carbohydrates, food types, packaging practices, and inert ingredient factors. This model was developed over the course of a several years and will be discussed separately in an upcoming article.

In my own case, I use lightweight foods wherever possible. Since commercial packaging typically contains a fair amount of waste, I'm also pretty careful about re-packaging most items in order to reduce both weight and bulk. For me, 2+ pounds of trail food typically provides around 3,500 calories, which is often only about half of my daily burn. Even at this reduced level, however, food is still the heaviest item in my pack. For a seven-day solo trip, my food, including two silnylon oversacks, usually weighs over 15 pounds, more than the combined weight of my tent, sleeping bag, pack and clothing, the four heaviest gear items I normally carry. 

To meet my actual daily caloric needs, I'd need to pack at least 30 pounds of food for a week-long trip (though I seriously doubt I could actually eat that much even if I could carry it). Further, if so required by local backcountry rules, a bear canister, or possibly even two, would add another 2 to 5 pounds to this load. So it's easy to see that there's a quickly-reached, practical limit to the amount of food that one can carry on the trail, even for a relatively short trip. Those who undertake extended trips usually need to re-supply every week or so. 

There's another factor that can limit calorie intact, especially during the early stages of a trip, and especially in the mountains. As the body adjusts to the sudden changes in environment and activity levels, appetite can suffer. That's particularly true if one ascends to fairly high altitudes, where it takes most people a few days to acclimate. In the past, I found that when traveling from my home at sea level in California to the Sierra Nevada mountains (and typically 7,000' to 12,000' elevations), I usually needed to force myself to eat for the first two or three days on the trail. I doubt that during this period, I averaged more than about a 2,000 calorie a day intake. Thereafter, however, my appetite would often return with a vengeance.

The Calorie Gap

If one expends 7,000 calories a day backpacking, but only consumes 3,500 calories, the difference must come from existing energy stores within the body. For most of us, that means fat burn (note that while some people who diet without exercising can also lose weight by consuming muscle tissue, doing so is not likely with backpackers, who are in fact, probably building muscle mass as they walk). And as any dieter knows, 3,500 calories of fat usage equates to one pound of weight loss. For those who are heavier, carry larger packs, or consume fewer calories, the rate of weight loss would be even greater, perhaps by a lot. A slightly chunky friend who undertook a trip to the Sierras several years ago managed to lose 22 pounds during the course of his two-week expedition (or over 1 pounds a day) and I have since learned that his experience is not atypical. 

This calorie gap is an effect that I've confirmed on my own trips, where I usually average about a 7 pound-per-week reduction rate. So as one ponders the potential significance of this phenomenon, a question might come to mind: How do long distance hikers that sometimes cover thousands of miles over the course of several months avoid wasting away into nothingness? 

Part of the answer is that as the human body sheds weight and becomes stronger and more aerobically tuned, it develops into more a efficient machine. The daily calorie burn of a reasonably lean, fit hiker carrying a lightweight pack might be "only" 4,000 calories if covering say, 15 miles a day. In October of 2001, Brian Robinson became the first person to hike the "Triple Crown" in a single year. The Triple Crown includes the Pacific Crest, the Continental Divide and the Appalachian Trails, America's three major north-south wilderness routes with a combined distance of nearly 7,400 miles. Robinson averaged in excess of 30 miles a day over demanding terrain and burned, by his own estimates, about 6,000 calories a day. In contrast, an overweight, less fit hiker carrying a conventional 35 to 45 pound pack might have required 10,000 calories or more to perform the same feat on any given day.

Another reason that long distance hikers endure is that they tend to gorge in trail towns. Brian Robinson, according to his journal, would devour masses of ice cream, pizza, hamburgers and other high calorie foods when at re-supply stops. He also reportedly consumed some 900 Snickers bars while on the march. As a result, by the end of his long journey, he had apparently neither gained nor lost a single pound relative to his starting weight of 155.

How are Backpacking Calorie Needs Determined?

The energy required to operate the human body is delivered through cellular metabolism and can be broken down as follows:


1. Basal metabolism refers to the production of the energy needed to fuel the body's basic infrastructure functions such as pumping blood, breathing, staying warm, thinking, waste elimination and other "staying alive" activities. The basal requirements exclude the energy necessary to digest food (see #2 below), but still account for the majority of the daily calories needed by most (especially inactive) people. For the "average man" that is often used by the USDA for "daily requirements" calculations, the 2,000 calories of daily energy necessary to function might come 75% to 85% from basal metabolism. The Harris-Benedict equations are widely regarded as among the most reliable ways to estimate basal metabolism rates and can be expressed as follows:


Daily basal calories for an adult male: 
66 + (6.3 x body weight in pounds) + (12.9 x height in inches) - (6.8 x age in years)


Daily basal calories for an adult female: 
655 + (4.3 x weight in pounds) + (4.7 x height in inches) - (4.7 x age in years)


Example:  For a 180 pound man that's 40 years old and is 5' 10" tall, the daily basal need would be about 1,830 calories.



2. Thermic effect metabolism refers to the energy produced by the body that's needed to digest and otherwise process food that is eaten. The thermic effect is layered on top of basal metabolism, and averages about 10% of the energy content of the food itself.


Example:  For our backpacker that consumes 3,500 calories a day, the thermic effect requirement is about 350 calories.



3. Activity-related metabolism is the the third layer of the body's energy production and depends on exertion levels. For the couch potato, this need is low, but for the hard working backpacker, it can be quite substantial. There are a large number of public Internet databases that can be used to estimate activity-related calorie requirements, though few deal explicitly with backpacking, especially in mountainous terrain. The Nutribase tables seem to be among the most complete (noting that table values displayed are for 30 minutes of each activity) though the calculation performed below was actually completed by averaging the results obtained across several databases. Relevant variables for backpacking include body weight, pack weight, walking speed and elevation gains and losses. The greater each of these variables, the more calories that are consumed.


Example:  For our sample backpacker who weighs 180 pounds (including clothes worn), carries a 35 pound pack, averages about 2 miles per hour through moderate terrain, and does not use trekking poles (more on this point below), a reasonable estimate of calories consumed is about 600 per hour. (Note that a heavier backpacker walking in particularly difficult terrain might use as much as 1,000 calories per hour according to some tables.) If he spends 7 hours a day actually walking, the related activity burn would be about 4,200 calories. In addition, if he spends two hours in the morning and two in the evening performing camp chores at a burn rate of about 300 calories per hour (comparable to moderately vigorous housework), he will expend another 1,200 calories or so for a total of about 5,400 activity-related calories.



The total daily metabolic demands for our sample backpacker could therefore be summed up as follows:



Basal metabolism


Thermic effect metabolism


Activity-related metabolism


Total daily calorie burn



If this same backpacker consumes 3,500 calories daily, he will experience a deficit of 4,080 calories and will probably lose in excess of 8 pounds over the course of a seven-day backpacking trip. As noted above, a heavier hiker walking in particularly challenging terrain could lose more, perhaps as much as 10 or 11 pounds, while a leaner, ultralight hiker would probably lose less (if any) weight. For those keeping score at home, it's probably worth noting that over the course of this trip, the daily calorie burn might decrease a bit as the food in the pack is consumed. But since these calculations are all approximations anyway, this effect probably has no material impact on the averages discussed here.



Bonus Calories?

An interesting trend that has developed mostly in Europe over the past few years is the growing popularity of "Nordic walking". Nordic walking is simply ambulating while using a pair of specially modified ski poles. The idea was apparently first embraced by Finnish cross country skiers who sought to maintain conditioning during the off-season and is simple in principal. By using a pair of poles of the appropriate length, walking can be transformed from a mostly lower-body exercise into a full-body workout (much like Nordic skiing). Proponents suggest that by involving the arms, shoulders and other upper-body muscles, the number of calories consumed can be boosted by anywhere from 20% to 60% (or more). A variety of Nordic walking resources can be found here.


A lot of backpackers, of course, already understand the value of using either a single walking stick or a pair of trekking poles. They are significant aids to balance on rough trails, are invaluable for fording streams, can be real knee-savers on steep descents and can be used to support tarps or tents in camp. However, not a lot has been written about the use of poles in fitness walking, at least in North America. Indeed, if one does a Google search on the term "Nordic walking", most of the hits returned are those of European websites.


For more than a dozen years, I used a single hiking staff on the trail. About two years ago, I switched to twin poles when backpacking and have become a believer in their value. When off trail, I also walk most days at least 5 miles, often at a lake near my house. Recently, I began using twin poles on these daily walks and and can feel a big difference over using no poles (even though these poles are not "officially" optimized for Nordic walking). I find that I take longer strides, walk faster, and generally work harder. I can also feel the effects in my arms and shoulders at the end of the walks. My experiences seems to be similar, in fact, to those of Emmett Berg, who recently wrote this article for the Los Angeles Times.


A 25% increase in energy usage through the use of trekking poles seems to be at the conservative end of current estimates, but if accurate, would add some 1,050 calories to the 4,200 walking calories calculated above, boosting the total daily calories from 7,580 to 8,630. Rather than a loss of 8 pounds per week, our sample backpacker would now lose over 10 pounds and our heavyweight might lose 12 pounds or more per week if using trekking poles. It bears remembering, however, that Nordic walking is still quite new, which means that the bonus calories discussed here should probably be viewed as somewhat speculative until further study can corroborate the claims.


Other Advantages

For those who aspire to shed pounds, backpacking offers some further advantages over alternative weight loss techniques:

  • Backpacking enforces a complete separation from everyday life in "civilization" (provided you leave your cell phone and pager at home). Once dwelling 24 hours a day in the wilderness, many of the stresses that normally dominate people's lives tend to quickly melt away, and one's focus almost universally shifts to the "here and now". Life boils down to simple pursuits like walking, eating, making camp and dealing with the new, and often immediate challenges encountered on the trail.

    From a weight loss perspective, this environment means that most of the day-to-day cues that can trigger over-eating at home will evaporate (Dr. Phil McGraw discusses these factors in his best selling book, The Ultimate Weight Solution: The 7 Keys to Weight Loss Freedom). With backpacking, one is forced to partake of a different way of living under conditions that are unusually conducive to locking-in commitments to lifestyle changes. 

  • Rather than serving as simply a means to a weight loss end, backpacking becomes, for many people, an end unto itself and provides a continuing reason to remain fit. Though I've been lucky enough to enjoy many amazing experiences in life, I usually regard my backcountry trips as among the most fulfilling. For me, the payoff for staying in shape through hiking and backpacking is that I get to do more hiking and backpacking. Or said another way, with backpacking, I'm able to do something I love while getting the exercise largely by accident.

  • Undertaking a week-long backpacking trip can become a commitment that's difficult to back away from, especially if traveling with others. When 25 miles deep in the wilderness, one is pretty much forced to stick with the program, even if experiencing some discomfort. At home, it's often too easy to bail out of a new diet or exercise regimen.

  • Even a relatively short backpacking trip can change a person profoundly and permanently. Besides losing weight, it's also possible (and perhaps likely) to gain new insights into one's own being. A feeling frequently expressed by backpackers after a trip is that they have a "...much better sense of what's important in life." Among the new priorities that often surface is the notion that one's own health is supremely valuable and should be more carefully nurtured after returning to the "real world". Along with a sense of spirituality that often engulfs those who truly connect with the wilderness, these psychic shifts may help in keeping the weight lost on the trail from returning once at home.

  • And finally, a big part of backpacking is, of course, about walking, which is regarded by most experts as one of the very best forms of exercise available. Walking is low impact and carries a relatively small risk of injury, even when carrying a pack. Given a reasonable level of starting fitness, backpacking is accessible by wide range of people and can be often pursued until very late in life. I've talked with several hikers in the Sierras, for example, that I'm sure were in their eighties (though they didn't volunteer and I didn't ask). The walking that's done in connection with backpacking is also one of the few forms of exercise than can be undertaken hour-after-hour for days, weeks or even months on end, accounting for much of its ability to produce significant health benefits.

Once a backpacker's weight loss goals are achieved, a wonderful thing can happen. Perhaps for the first time in his or her life, the newly slimmed hiker can begin worrying about actually getting enough calories (especially on the trail) to avoid further weight loss. He or she might even develop a fondness for Snickers bars or begin using old backpacker's tricks like adding olive oil to meals in order to pump up the calorie content.


All told, I believe that Americans could benefit greatly by "hitting the trail" in large numbers in order to shed pounds and improve fitness levels. Though some existing backpackers who crave solitude in the wilderness might worry about an upsurge in interest in backpacking, I believe there's still enough wild space out there for everybody. Internet backpacking sites, along with books like Chris Townsend's excellent Backpackers Handbook (third edition, published in October, 2004) are terrific resources for those just getting started. Equipment has also improved significantly over the past ten years, making it easier than ever to travel safely and comfortably in the wilderness.


And for those who already backpack, I would close by repeating my suggestion that you consider first concentrating on optimizing your body weight before spending a lot of energy fretting over a few extra ounces of pack weight. In fact, if you're overweight, you might even take some comfort in knowing that a little extra gear (as well as the extra body pounds you're carrying) can actually help you burn more calories on the trail each day.


You can submit or read comments about this article here.

Copyright 2005 James E. Wood. All Rights Reserved.