Calories and Hydration on Mountain and Wild Camping Trips

A practical guide to staying fuelled, hydrated and making good decisions in the hills.

People often underestimate how quickly a mountain day can drain energy — especially when you add a rucksack, rough ground, wind, rain and multiple days in a row. The result can be a slow fade: tired legs, cold hands, sloppy navigation, poor decisions, and a day that feels harder than it needs to.

This guide is here to explain the “why” behind food and fluids on mountain and wild camping trips. It’s not about perfect numbers or fancy nutrition. Instead, it’s about simple habits that keep you moving well and enjoying the experience.

Why mountain days burn more energy than you expect

A “normal” day at home and a day in the hills are not the same thing. Even at a steady pace, you’re often working harder for longer: uneven surfaces, constant micro-adjustments, and sustained effort up and down steep terrain.

Add in a rucksack, wind chill, cold hands, wet clothing and shorter daylight (in winter), and your body spends more energy just staying warm and keeping things ticking over. Over multiple days, small shortfalls add up fast.

Calories: why people run low (and don’t notice until later)

The most common problem we see isn’t that people bring no food — it’s that the food they bring doesn’t match the day. On long or multi-day trips, “light lunch and a couple of snack bars” often isn’t enough.

Another common issue is appetite. Some people don’t feel hungry when they’re concentrating, moving in bad weather, or climbing steep ground. Others are fine on Day 1 and then fade on Day 2 and Day 3 because they never fully refuelled.

What works well in the real world

• Bring more than you think you’ll need, then treat any leftovers as a win.
• Include snacks you can eat quickly without stopping for long.
• Favour foods that still feel appealing when you’re cold or tired.
• On multi-day trips, think about recovery as well as the day’s walking.

Hydration without thirst: why it catches people out

Hydration is not just a hot-weather issue. In cold or windy conditions, people often drink less because they don’t feel thirsty, they don’t want to stop, or they don’t want to take gloves off and faff with bottles.

Mild dehydration can show up as headaches, fatigue, poor concentration and feeling unusually cold. It also makes it harder to eat well, because digestion and appetite can take a hit.

Simple hydration habits that help

• Start the day already hydrated rather than “catching up later”.
• Drink little and often, not just at lunch.
• If you’re sweating heavily or working hard, consider adding electrolytes to one bottle.
• In winter, use insulated bottles or keep water where it won’t freeze.

Timing beats totals: eat before you feel tired

A helpful rule on hill days is to eat and drink proactively. Once you’re already empty, cold or “bonked”, it takes longer to recover. Small, regular snacks are often more effective than big gaps followed by one large stop.

What guides commonly see go wrong

The same patterns come up again and again, even with fit and experienced walkers. Not because people are careless — but because the hills have a way of making simple tasks feel less important in the moment.

• “I didn’t feel hungry, so I didn’t eat much.”
• “I only drank when we stopped, and we didn’t stop often.”
• Food that’s hard to eat in the cold (frozen bars, awkward packaging, very dry snacks).
• Not bringing enough quick snacks for steep sections or bad weather.
• On multi-day trips: under-eating early, then struggling to catch up later.

How this links to our equipment and kit lists

Our equipment lists are designed to help you avoid the common problems above without turning your preparation into a science project. If you want a clear checklist for your course or trip, the full equipment and kit lists are available here: /equipment-and-kit-lists/

If you’re unsure what’s appropriate for your course dates, just ask — we’ll point you in the right direction.