You already know carbs fuel the climb and fat keeps the engine running on the long, slow days. Protein gets less attention because it doesn't feel like fuel. It isn't, really. It's what you rebuild with. And on a multi-day trip, what you rebuild with is the difference between waking up on day four feeling worked-in versus worn-down.
Here's the problem most experienced hikers run into: you know roughly what good trail nutrition looks like, you pack calorie-dense food to keep pack weight down, and somewhere in that optimisation protein quietly falls off the table. Trail food skews carb-and-fat heavy by design, because that's where the cheap, light, shelf-stable calories live. Protein is heavier per usable gram, perishable in its best forms, and easy to under-pack without noticing until your legs stop recovering overnight.
This piece is about getting the number right and then actually hitting it in the field. Not the RDA, which was never written for someone burning 4,000 to 5,000 calories a day under a loaded pack. The real working targets, where they come from, and how to build them into a food bag that still makes sense on the scale.
The baseline number is wrong for you, and here's why
The figure you've seen quoted everywhere is 0.8 g of protein per kilogram of body weight per day. For a 70 kg hiker that's 56 g. It's the number on the back of the cereal box and the one most general nutrition advice still leans on.
It's also the wrong starting point for anyone doing what you do. The 0.8 g/kg RDA is set to prevent deficiency in a sedentary adult. It is the floor that stops you losing nitrogen balance while sitting still, not the amount that supports recovery, adaptation, and lean mass retention under sustained load. Treating it as a target rather than a minimum is the single most common protein mistake among otherwise well-prepared hikers.
The endurance research has moved a long way past 0.8. The current evidence, built largely on the indicator amino acid oxidation method, which measures protein requirement far more sensitively than the older nitrogen-balance studies, puts the requirement for endurance-trained adults at around 1.8 g/kg/day on a normal training day [1]. That's roughly 50% higher than the sedentary figure, and it's specifically the amount that supports the repair and remodelling of muscle stressed by repeated endurance work.
Multi-day hiking under a pack sits squarely in that endurance-stress category, often more so, because you're combining the cardiovascular load of long-duration movement with the eccentric muscle damage of descending under weight. So 1.8 g/kg/day is the number to anchor on. For a 70 kg hiker that's about 126 g per day. For 80 kg, around 144 g. Those are large numbers, and they should be, because the demand is real.
When you need to push past 1.8
The 1.8 figure is the standard training-day target. Two situations on the trail push it higher.
The first is the rest or recovery day. Counterintuitively, the research recommends increasing protein on lower-activity days to around 2.0 g/kg/day [1]. The logic is that recovery is when the repair work actually happens; the building happens during the rest, not during the effort, so the substrate needs to be there. On a zero day in town or a deliberately short mileage day, that's when you eat the big restaurant meal without guilt.
The second is operating in an energy deficit, which is the default state on most serious multi-day trips. You almost never match a 4,000 to 5,000 calorie burn with intake; the food's too heavy and your appetite lags behind your output. When total calories are short, protein does double duty: it's the macronutrient that most strongly protects lean mass when the body is otherwise inclined to break muscle down for fuel.
This is where the expedition literature gets specific. Work on high-altitude and military expeditionary settings, where sustained negative energy balance is unavoidable, points to a minimum of around 1.6 g/kg/day to support fat-free mass retention during a deficit, with controlled trials testing intakes as high as 2.4 g/kg/day to protect muscle protein synthesis under energy restriction [2][3]. The practical read: on a long trip where you know you're under-eating, treating 2.0 g/kg as the target rather than the ceiling is well-justified, and there's no evidence it does any harm in healthy hikers.
There's a hard reality buried in those same studies, though. At genuinely severe energy deficits and high altitude, protein alone won't fully prevent fat-free mass loss; one 21-day study found fat-free mass dropped regardless of protein intake when the deficit was deep enough [2]. Protein blunts the loss, it doesn't abolish it. The lesson isn't to abandon the protein target; it's that on extended trips, closing the calorie gap matters as much as hitting the protein number.
Total daily protein isn't the whole story: distribution matters
Here's the part that catches experienced hikers who do pack enough protein. You can hit 130 g a day and still leave gains on the table if all of it arrives in one big dinner.
Muscle protein synthesis works in pulses, not as a continuous drip. Each adequate protein feed switches synthesis on for a few hours, then it settles back down regardless of how much protein is still circulating. To switch it on you have to clear what's called the leucine threshold. Leucine is the branched-chain amino acid that acts as the trigger; muscle effectively senses a meal by detecting a leucine spike, and below a certain dose it doesn't fully fire. That threshold sits at roughly 2.5 to 3 g of leucine per meal, which works out to about 25 to 40 g of high-quality protein depending on the source [4].
Practically, that means the way to maximise daily synthesis is to hit that threshold three to five times across the day, not once. The endurance position stand puts a finer point on it: target a per-meal protein dose of around 0.5 g/kg in the immediate post-exercise window to maximally drive the remodelling of damaged muscle [1]. For a 70 kg hiker, that's about 35 g in the meal after you stop walking.
The trail eating pattern works directly against this. The classic approach is to graze on carbs all day (trail mix, bars, gels) and load protein into one camp dinner. That front-loads the threshold once and leaves the muscle under-stimulated through the entire active day. You don't need to overhaul it, but shifting some protein into a mid-day meal and a solid post-hike feed, rather than saving it all for the freeze-dried dinner, makes the protein you're already carrying work harder.
A workable distribution for a 70 kg hiker targeting ~125 g:
- Breakfast: 30 g (protein oats, milk powder, a couple of eggs in front-country)
- Lunch / long break: 25–30 g (jerky, hard cheese, tuna pouch)
- Post-hike, at camp: 35 g (the recovery feed, highest priority dose)
- Dinner: 30 g (protein-fortified meal or added TVP)
That's four threshold-clearing feeds and it lands the daily total without a single heroic 90 g sitting.
Quality, not just quantity: leucine and complete sources
Not all protein clears the leucine threshold equally. Animal proteins (whey, eggs, meat, dairy) are leucine-dense and complete, meaning they carry all essential amino acids in usable ratios; you hit the threshold with roughly 25 g. Most plant proteins are lower in leucine and often limiting in one or more essential amino acids, so you need a larger dose, closer to 35 to 40 g, and ideally a mix of sources to round out the amino acid profile.
This isn't an argument against plant-based trail eating, which works fine. It's an argument for being deliberate about it: if you're packing lentils, TVP, soy, and nut-based proteins, lean toward the higher end of the per-meal dose and combine sources (legume plus grain, for instance) rather than relying on a single plant protein to do the job. Soy and pea protein isolates are the closest plant options to the leucine density of animal sources, which is why they're worth their place in a powder.
Why this matters more than it feels like it does
The cost of under-eating protein on the trail isn't dramatic on day one. It compounds.
Short-term, the immediate signs of inadequate protein are the ones easy to misattribute to "just being tired": persistent soreness that doesn't clear overnight, sluggish recovery, the sense that your legs are getting worse rather than adapting as the days stack up [5]. Because everyone expects to be tired on a long trip, it's easy to write this off as normal fatigue when it's partly a repair deficit.
The longer-term picture is sharper, and it's where the thru-hiking physiology research earns its keep. Extended multi-week hiking puts the body in a prolonged stress-and-deficit state that drives measurable muscle loss, particularly in the upper body, hence the well-known "T-Rex syndrome" of thru-hikers whose legs are granite and whose arms have wasted. The same state contributes to significant bone density loss; one study of PCT hikers found spinal bone density dropped by around 8.5%, comparable to roughly two decades of ageing, though it largely recovered 8 to 12 months post-hike. Adequate protein and adequate total energy are the two mitigation levers that consistently come up. You can't fully out-eat the stress of a months-long trip, but you can blunt the muscle and recovery cost substantially, and protein is half of that equation.
If you're an older hiker, this gets more pointed. Anabolic resistance, the blunting of the muscle's response to a given protein dose, increases with age. Past your forties or so, the same 25 g feed that fully fires synthesis in a younger hiker may not, which is why protein recommendations for older adults sit at 1.2 to 1.6 g/kg even at rest, and why the per-meal dose matters more, not less, when you're loading the pack at 55 than at 25 [6]. The threshold doesn't move down with age; if anything you need to clear it more deliberately.
How to actually carry it: the trail food problem
All of the above runs into one wall: protein is the inconvenient macro to carry. Its best, most leucine-dense forms (fresh meat, eggs, dairy) are heavy and perishable. The shelf-stable, light options are either lower in protein per gram or built around carbs and fat. Hitting 125 g a day from a food bag you're also trying to keep under control on the scale takes intent.
The way through is to think in terms of protein-per-100g and protein-per-calorie, not just absolute grams, and to lean on a few categories that punch above their weight.
| Trail source | Protein (per 100g) | Notes |
|---|---|---|
| Whey / soy protein isolate powder | 70–90 g | Highest protein density you can carry; mixes into water, oats, coffee |
| Biltong / dried jerky | 50–55 g | Far higher protein density than wet jerky; leucine-complete |
| Textured vegetable protein (TVP) | ~50 g dry | Rehydrates into meals; cheap, light, vegan |
| Parmesan / hard aged cheese | ~35 g | Protein plus fat; holds up unrefrigerated for days |
| Tuna / salmon pouch | ~25 g per pouch | Complete protein, no cooking, adds variety |
| Peanut / nut butter | ~22–25 g | Combination food: protein, fat, calories together |
| Dehydrated lentils / chickpeas | ~9 g cooked | Lower density; combine with grain for complete profile |
The single most effective lever for most hikers is protein powder. At 70 to 90 g of protein per 100 g, it's the densest source you can carry by a wide margin, it weighs almost nothing relative to its contribution, and it slots into things you're already eating (morning oats, recovery shake, even coffee). A 30 g scoop is a threshold-clearing feed in a sandwich bag. If you take one thing from this article into your next food bag, it's a few pre-portioned bags of isolate.
The second is biltong or properly dried jerky over the wetter commercial stuff. The drier it is, the higher the protein-per-gram, because you're not paying pack weight to carry water in the meat. It travels well, it's a complete protein, and it makes a genuine lunch feed rather than a token snack.
The "combination foods" approach, favoured by ultralight hikers, is the third lever and the one that reconciles protein with the calorie-density goal: nut butters, quinoa, chia, TVP, chickpeas, and soy milk powder all deliver protein alongside fat, fibre, and carbs in the same dense package, so you're not paying a weight penalty to bolt protein onto a carb-based bag. You're choosing base foods that carry protein inside them.
A worked example: three days, 75 kg hiker
Target at 1.8 g/kg is about 135 g/day. Here's how that builds without a heavy bag:
Breakfast (~32 g): 80 g oats cooked with 30 g whey isolate and a tablespoon of nut butter. Hits the morning threshold and front-loads calories.
Trail snacks through the morning: mostly carbs and fat for fuel (this is where the carbs belong), with a 30 g portion of biltong as a mid-morning feed contributing ~16 g.
Long lunch break (~28 g): a tuna pouch (~25 g) plus a chunk of parmesan, eaten as a real sit-down rather than grazed.
Post-hike at camp (~35 g): the priority feed. A second whey shake (30 g protein) within the first hour of stopping, while you set up. This is the 0.5 g/kg post-exercise dose the research singles out [1].
Dinner (~30 g): a freeze-dried meal bulked with a handful of TVP, or a from-scratch meal built on lentils and quinoa.
That's roughly 140 g across five threshold-aware feeds, built from food that's light, mostly shelf-stable, and doesn't blow out the calorie-density goal. The whey does the heavy lifting on density; the biltong and tuna give you complete protein and variety; the combination foods carry protein without a weight penalty.
The bottom line
Anchor on 1.8 g/kg/day as your normal-trip target, not the 0.8 RDA. Push toward 2.0 g/kg on recovery days and when you know you're running an energy deficit on a longer trip. Distribute it across three to five feeds of 25 to 40 g each rather than one big dinner, and protect the post-hike dose in particular. Lean on protein isolate, dry-cured meats, and combination foods to hit the number without wrecking your pack weight. And remember that protein is only half the equation on extended trips: it blunts muscle and recovery losses, but it can't fully compensate for a deep calorie deficit, so close that gap where you can.
Get this right and the difference shows up exactly where it matters: in how your legs feel on day four, and in how much of yourself you bring home from a long trip.
Train hard. Fuel right. Pack smart. Go further.
References
- Endurance protein review (indicator amino acid oxidation method): endurance-trained adults require ~1.8 g/kg/day on training days, ~2.0 g/kg/day on recovery days, and ~0.5 g/kg per meal post-exercise. Protein Nutrition for Endurance Athletes: A Metabolic Focus on Promoting Recovery and Training Adaptation, PMC. https://pmc.ncbi.nlm.nih.gov/articles/PMC12152099/
- Negative energy balance at altitude and fat-free mass: ~1.6 g/kg/day supports FFM retention during deficit; severe deficits reduce FFM regardless of protein intake. Nutritional Strategies for the Preservation of Fat Free Mass at High Altitude, PMC. https://pmc.ncbi.nlm.nih.gov/articles/PMC3942726/
- Dietary protein and lean mass during energy deficit in active-duty military personnel (intakes >0.8 up to ~1.6–2.4 g/kg/day tested). The Role of Dietary Protein in Body Weight Regulation among Active-Duty Military Personnel during Energy Deficit: A Systematic Review, PMC. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10536394/
- Leucine threshold (~2.5–3 g leucine, ~25–40 g protein per meal) and pulsatile muscle protein synthesis. International Society of Sports Nutrition Position Stand: protein and exercise, PMC. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5477153/
- Protein deficiency signs in active people (fatigue, slowed recovery, muscle breakdown). How Much Protein Is Required for Hiking, Outside+ / Outside app (Madi Niemi, fitness coach, cited).
- Protein for older adults and anabolic resistance (1.2–1.6 g/kg/day; blunted MPS response with age). Nutritional Interventions: Dietary Protein Needs and Influences on Skeletal Muscle of Older Adults, PMC. https://pmc.ncbi.nlm.nih.gov/articles/PMC10272976/
