We use peer-reviewed research from the U.S. Army to estimate energy expenditure during loaded hiking—accounting for factors that consumer tools often overlook.
"Pack 2 lbs of food per day." It's the advice you'll find in every backpacking guide. But it doesn't account for:
A 120 lb ultralight hiker with a 15 lb pack on a flat trail has very different calorie needs than a 200 lb hunter with a 60 lb pack climbing 4,000 feet. Yet the "2 lbs per day" rule treats them the same.
The result? Some hikers bonk on Day 3. Others lose 10+ lbs on a thru-hike. And many carry pounds of uneaten food home because they planned for worst-case scenarios.
LCDA stands for Load Carriage Decision Aid. It's a metabolic prediction equation developed by the US Army Research Institute of Environmental Medicine (USARIEM) specifically for predicting energy expenditure during loaded marches.
The LCDA equation was built from the ground up to handle the unique demands of carrying heavy loads over varied terrain—the kind of conditions backpackers, thru-hikers, and backcountry hunters encounter.
The research was published in Medicine & Science in Sports & Exercise in 2022 after validation against measured energy expenditure in controlled studies. It accounts for all the factors that generic calculators miss.
Peer-reviewed research used in the LCDA model shows that each of these factors affects your calorie burn. The equation combines them into a single, validated prediction.
Heavier hikers burn more calories moving their mass. The equation scales appropriately.
A 200 lb hiker burns ~30% more than a 150 lb hiker at the same pace.
This is the big one. Carrying a load dramatically increases energy expenditure in a non-linear way.
A 40 lb pack can increase calorie burn by 30-50% vs. unloaded hiking.
Faster hiking burns more calories per hour, but the relationship isn't linear—there's an efficiency sweet spot.
Hiking at 3.5 mph burns significantly more than 2.5 mph.
Different surfaces require different amounts of energy. Sand is exhausting. Packed trails are efficient.
Walking on sand requires 50% more energy than pavement.
Uphills and downhills have very different energy costs. Steep descents actually require more energy than gentle ones.
A 10% uphill grade increases energy cost by ~70%.
These coefficients come from Pandolf et al.'s research on terrain effects, incorporated into the LCDA model. They represent how much harder it is to walk on each surface compared to a paved road.
| Terrain | Coefficient | Impact |
|---|---|---|
| Paved Road | 1.0 | Baseline |
| Grass | 1.08 | +8% energy |
| Dirt Road | 1.2 | +20% energy |
| Trail | 1.15 | +15% energy |
| Light Brush | 1.15 | +15% energy |
| Heavy Brush | 1.35 | +35% energy |
| Packed Snow | 1.3 | +30% energy |
| Sand | 1.5 | +50% energy |
| Loose Snow | 1.5 | +50% energy |
| Swamp | 3.5 | +250% energy |
Looney DP, Santee WR, Karis AJ, Blanchard LA, Rome MN, Carter AJ, Potter AW. Modeling the Metabolic Costs of Heavy Military Backpacking. Med Sci Sports Exerc. 2022 Apr 1;54(4):646-654.
Additional research incorporated into our model includes terrain coefficients from Pandolf et al. and grade adjustment factors from Santee et al.
MTNMetrics provides calorie estimates based on peer-reviewed research to help with trip planning. These are estimates only—individual energy expenditure varies based on fitness level, efficiency, altitude acclimatization, weather conditions, and other factors not captured by any equation.
The LCDA equation was developed and validated for military applications and has shown good correlation with measured energy expenditure in research settings. However, actual results may differ. Use these estimates as a planning starting point, not a guarantee.
MTNMetrics is not affiliated with or endorsed by the U.S. Department of Defense or the U.S. Army Research Institute of Environmental Medicine.
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