After an 11-week aerobic endurance training period from June 3 to August 22, 2025, I improved my fitness sufficiently to reduce my caloric expenditure while hiking by 20%.
I measured this reduction on one of my test hiking routes – a rocky trail with an 8% grade, high-steps in the steepest sections, and at a starting elevation of over 8,500 feet ASL. On June 3, I burned 205 kcal/mile on the test hike. By August 22, my caloric burn at the same pace, same pack weight, and same environmental condition reduced my burn rate to 165 kcal/mile.
I’m still working on this case study, but for now, consider the implications of reducing calorie expenditure by 20% in response to training.
- Can I now carry less food weight when planning a backpacking trip?
- Will I cannibalize less muscle mass during long trips in response to the inevitable caloric restriction that comes with backpacking?
- Can I maintain my current food weight and increase my output (e.g., speed or mileage)?
- Can I carry a heavier pack with a few more trail luxuries or additional food for extending my trip?
I could answer ‘yes’ to all four questions. Now I have to decide what my goals are.
This exercise has repeated itself over the years for me. It remains a key reason why I focus more on physiological preparation, rather than (just) gear weight, when planning big trips.
The fitness program I designed, and the measurement and validation of its performance, was based on the Metabolic Energy Mile (MEM) Framework – which will form the foundation of an entirely new component of our Basecamp Live curriculum this fall. This represents the most significant update to Basecamp we’ve made in several years.
It’s based on a simple cycling of different training phases (some simultaneous, some not) that requires actually measuring and optimizing your body’s response to training, so you don’t stay in one phase too long and you recover effectively to achieve optimum adaptation to training:
- Core conditioning.
- Aerobic base development (increase AeT).
- Lower body hypertrophy (muscle growth).
- Supra-AeT conditioning (narrow the AeT/AnT gap).
- Lower body max strength development.
- Lower body muscle endurance development.
So much more to say about this, in due time.
Discussion
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Companion forum thread to: 11 weeks of aerobic endurance training reduced my calorie expenditure by 20%
An 11-week endurance training program cut my hiking calorie burn by 20%. Can the Metabolic Energy Mile (MEM) Framework help reduce food weight, improve efficiency, and transform backpacking performance?
How was the caloric expenditure measured?
Chest strap HRM – with validation check against my VO2-HR plots from calorimetry tests (which I do once/month). Chest strap HRM (indirect measurement) is consistently within about 5-7% of the calorimetry tests (which are direct measurements).
Cool, thanks for that. From my (admittedly tenuous) understanding of endurance science, long-term training typically yields 5–15% efficiency improvements in gross economy over months/years…so, a 20% gain in 11 weeks is at the high end. Certainly not impossible, just much more than I would’ve expected…but if you’re benching your monitor against direct testing and seeing consistent results, that’s pretty solid data. Wish I could see results like that!
Agreed, I don’t get these kinds of results often in a training cycle, and admittedly, I started in June in a pretty detrained state…!
I got your de-trained state right here. 🤣
I’m looking forward to seeing more details on what you did; I need better strategies for getting into and staying in shape.
Ryan, Interesting article but personally, it would me to appreciate the results if you could elaborate on the relative significance of the results. For trips over 7 days, I usually try to get some daily hiking in weeks before the trip. When going to altitude (+10k) I add a lot of hill work (+1000 foot climbs0. Surely not nearly the extent of what you were doing.
I suspect that after a through hike (+250 miles), many people would end up with the same results: efficient usage of calories. The same is probably true for professional athletes (trail guides and such).
What would be the program for an average Joe? What would be the return on investment sort of speak. That is where I am trying to wrap my mind around: what effort and what results would I possibly see?
Jon, I can’t speak for Ryan, but I’ll quote myself…
…and add some emphasis: 20% gains in that time span for anyone except a raw beginner are insane. Like, that result is right on the line between “Holy f***, are you serious?” and “Cool story, bro”…but given that Ryan has been measuring the results in a documented and reliable way, they’re valid. That’s why Ryan being in any kind of untrained state is important: when you’re lower down on the fitness ladder in any way, gains come quick and fast. Doesn’t matter if you’re hiking, running, lifting, getting into bar fights with orcas, whatevs: when you’re starting out, the body has tons of room to improve and it wants to do so…so growth/gain happens fast even with moderate effort. As you go up in fitness, however, it gets harder and harder to improve; eventually you reach physiological and genetic limits, and getting even 0.5% better at your activity or sport in requires incredible effort. So yeah, getting 20% better at hiking after three months isn’t out of reach for a beginner – it’s more likely than not – but for someone that’s been doing it for years and years, it’s a significant gain: they have an existent baseline of fitness that doesn’t easily go away, even when they’re relatively detrained.
Like you, I’m also interested in seeing the actual program…and that’s because I’m a big believer in targeted training for your activity. To an extent, you’re correct that doing a 250-mile hike will probably lead to improvements in caloric efficiency… but it won’t do it to the same level as a targeted and effective training program. You’ll get better at doing everything a 250-mile hike requires – moving efficiently, packing well, hydrating, resting correctly, putting your feet in the correct place on the trail, etc – but spending the same amount of time on doing nothing but energy-efficiency training is gonna absolutely blow that hike out of the water in terms of gains. That’s why marathon runners don’t just run marathons over and over again in order to train: it doesn’t actually help them improve as much as a program that’s designed to improve whatever they’re targeting for improvement.
I found a great example of this in Ed Viesturs’ book, in which he talked about training for his sport (alpine climbing) by doing exactly that: climbing. He thought he was in pretty good shape until a coach took him into the gym, started him on some weights and exercises, and absolutely crushed him with a training regimen. Result: easier climbs in the following season, due to increased strength, joint durability, endurance, etc.
I personally think that most every hiker, climber, backpacker, or outdoors-flavored person could do a lot to increase their fitness and enjoyment of their activities by spending more time actively training for them; myself most of all, and I’m the averagest of Joes. Thus, I’m also very interested in seeing the particulars of Ryan’s training cycle.
Apologies if this was too much of a hijack, but it’s an area of deep interest to me so I wanted to give some further insight as to why I said what I said, earlier.
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