The number of calories you burn on a hike varies considerably between people, trails, and conditions. Two hikers walking the same 15km route can have very different energy expenditures depending on their body weight, pack load, fitness level, and the terrain underfoot.
Understanding what drives calorie burn matters for more than weight management. On multi-day walks especially, underestimating your energy needs leads to inadequate food planning, accelerated fatigue, and reduced capacity to make good decisions when conditions get harder. Energy management is a core part of preparing for any serious walk.
Body Weight
Body weight is one of the strongest predictors of energy expenditure on the trail. Moving a heavier body over distance requires more work from your muscles, cardiovascular system, and stabilising structures with every step.
As a general reference, a person weighing around 70kg burns approximately 1,800 kilojoules per hour of moderate hiking. At 90kg, that rises to around 2,300 kilojoules per hour on similar terrain. The difference compounds significantly over a long day.
Pack Weight
Every kilogram of pack weight adds to your energy expenditure. Estimates suggest each additional kilogram of load increases energy use by at least 20 kilojoules per hour. That figure grows with terrain difficulty.
On a day walk with a light pack this is a minor factor. On a multi-day walk carrying a tent, sleeping system, food, and water, the cumulative effect is substantial. A loaded pack of 18 to 22kg significantly changes how your body responds over a long day, particularly on the descent when joint load increases sharply.
Pack weight also interacts with fatigue. A load that feels manageable at 8am will feel considerably heavier by early afternoon, which affects pace, foot placement, and decision-making.
Terrain Type
Terrain has a dramatic effect on energy expenditure that many hikers underestimate when planning food and timing.
A 5% incline can increase energy expenditure by around 50% compared to flat ground. Steep sustained climbs push that significantly higher. Rough, uneven terrain adds a further 10 to 30% above flat walking because your body is constantly stabilising against unpredictable surface changes.
Combining steep gradient with rough ground produces the highest energy demands of any hiking condition. Australian alpine terrain, rocky ridgelines, and off-track scrub travel all fall into this category.
Distance and Duration
Total energy expenditure scales with distance and time on the trail. This is straightforward, but the outdoor environment adds an important dimension.
Research tracking walkers, joggers, and hikers in Australian national parks found that hikers consistently pushed themselves harder and burned more calories than those exercising on flat, controlled surfaces. The varied terrain, environmental engagement, and natural motivation of outdoor walking tends to drive higher sustained effort than indoor exercise at a comparable perceived intensity.
Speed and Intensity
Moving faster burns more calories, but the relationship is not linear. Higher speeds produce disproportionately higher energy demands, particularly once you move above a comfortable walking pace.
On steep or rough ground, maintaining a fast pace becomes physically costly very quickly. A steady, controlled pace on challenging terrain often produces higher total energy expenditure than pushing speed on easier ground.
Sustained higher-intensity hiking also elevates your metabolic rate for a period after the walk ends. This effect can persist for several hours following a hard day on the trail, which is worth accounting for when planning post-walk food intake on multi-day trips.
Fitness Level
A fitter hiker burns fewer calories performing the same task as a less conditioned one. The body adapts to regular physical demands and becomes more efficient over time.
This matters for planning. Experienced hikers with a strong aerobic base will need to account for their improved efficiency when estimating food requirements, particularly if they are used to training at higher intensities. It also means that maintaining your calorie burn over time requires progressively increasing the challenge of your walks through distance, elevation, or pack weight.
Fitness also affects how fatigue accumulates across a multi-day walk. A well-conditioned hiker can sustain output more consistently and recover more effectively overnight, which has direct implications for safety and decision-making on longer routes.
Planning Your Energy Intake
For day walks, most people carry enough food without deliberate planning. For walks beyond one day, it is worth estimating your daily energy expenditure and planning food accordingly.
A rough working figure for a moderate multi-day walk with a loaded pack is 2,500 to 4,000 kilojoules per hour of active hiking, depending on the factors above. A full day covering 20km with 1,200m of elevation gain in warm conditions will sit toward the upper end of that range for most walkers.
Carrying insufficient food on a multi-day walk is not just uncomfortable. It accelerates physical fatigue, reduces cognitive function, and impairs the kind of judgement you need most in remote terrain. Food planning deserves the same attention as water planning and gear selection.
For broader preparation guidance see the fitness preparation guide and the first aid kit essentials for multi-day hiking.
