Britain’s hills, moors, and coastal paths are as beautiful as they are demanding. From a blustery ridge in Snowdonia to a sun-baked section of the South Downs Way, your body is constantly juggling energy use, temperature control, and hydration. Get the fuelling right and miles feel manageable; get it wrong and even a short climb can feel twice as long. This guide is designed to help you plan your nutrition for outdoor days so that food and drink support your route—not the other way round.
Outdoor travel places a steady, often unpredictable load on your body. Unlike a treadmill session, pace, gradient, wind, and footing change minute by minute. Understanding these demands sets the stage for a fuelling plan that actually works.
Walking or hiking at a brisk pace typically runs on a mix of fat and carbohydrate. The steeper the gradient or the heavier the pack, the more your body leans on glycogen (stored carbohydrate) for quick energy. On rolling paths you might burn roughly 300–500 kcal per hour; throw in long climbs, soft sand, peat bog, or scree and that can rise to 600–800 kcal per hour. Because glycogen stores are limited, long days need a steady trickle of energy to keep legs lively and decision-making sharp.
Footing matters. Rocky steps on Scafell Pike, boggy sections on the Pennine Way, or wet roots in the Cairngorms demand more from stabilising muscles and spike energy cost. Every kilogram in your pack also adds up—an extra 5–8 kg can turn a moderate hill day into a true workout. Elevation gain is the big multiplier: 800–1,200 metres of ascent in a day can feel like a different sport compared with a flat coastal stroll, even if the distance in miles is the same.
British weather swings quickly. A cool 12°C with drizzle can lull you into under-fuelling, even as wind chill pushes your body to burn more to stay warm. At the other end, a still 24°C day on exposed upland can accelerate sweat loss and increase reliance on fluids and electrolytes to keep nerve and muscle function ticking over. Headwinds, wet kit, and repeated stops to add or remove layers also subtly increase effort and energy use.
Fluid needs vary with pace, clothing, and conditions. Many people lose around 0.4–0.8 litres of sweat per hour in temperate weather, rising above 1 litre in warm, humid spells or on hard climbs. Sweat contains sodium and other minerals; as losses mount, you may notice heavy legs, cramp twinges, or a dip in concentration. Matching fluid intake to conditions—and including a source of electrolytes over longer efforts—helps maintain even pacing and good judgement.
It’s not just muscles that tire. Navigating with an OS map, judging a river crossing, or choosing a safer line off a ridge all require brainpower. Low energy and insufficient fluids can quietly erode attention and balance. That’s why consistent fuelling is both a performance enhancer and a safety habit, especially when terrain or weather is marginal.
Carrying the right supplies is always a balancing act: you want enough energy to keep going without weighing yourself down. The best solutions fit easily into a small rucksack pocket, survive a changeable British climate, and can be eaten without needing to stop for long.
Many outdoor adventurers swear by time-tested snacks from the high street. Oat bars, flapjacks, dried fruit, or a banana slipped into the side pocket of a bag all provide quick carbohydrate energy. These are cheap, easy to find, and often comforting after miles of rough terrain. The downside is bulk and perishability; a banana fares badly after four hours at the bottom of a pack.
For those wanting more compact fuelling, purpose-made sports products are designed to deliver carbohydrate in small, durable packets. Energy chews, drink powders, and electrolyte gels fall into this category. Gels in particular are lightweight, portion-controlled, and quick to consume even on the move. Their packaging fits neatly in pockets, and they don’t melt in warmer weather like chocolate bars often do.
Sweet foods are convenient but can become unappealing over long days. Including savoury options—such as mini oatcakes, nut butters, or even a small wrap—helps keep appetite steady and prevents “taste fatigue”. Portable savoury snacks are also a morale boost on longer treks, breaking up the monotony of sugary fuelling.
Outdoor food must handle rain, cold, and being squashed under waterproofs. Resealable bags or lightweight boxes keep items dry and intact. Wrapping bars or homemade flapjacks in greaseproof paper with a layer of foil makes them both packable and resistant to sogginess. Sports gels and sealed packets have the advantage of being water-resistant and easy to stash without fuss.
Keep items in separate small pockets so you don’t have to unpack your entire bag for one snack.
Pack a mix of quick-access items (like gels) and more substantial options for rest stops.
Carry waste bags; mountain and moorland areas leave no excuse for litter.
Even the best-prepared adventure can be thrown off by weather shifts, extended mileage, or unexpected detours. Planning nutrition and hydration with flexibility in mind helps ensure you don’t run short when conditions turn.
Routes often take longer than expected, whether due to a slow group pace, difficult terrain, or navigation errors. A good rule of thumb is to carry at least one extra fuelling option beyond what you think you’ll need. For example, if your walk is planned for four hours, bring enough snacks or electrolyte gels for five. That extra reserve is reassuring when a mist descends or a climb proves steeper than expected.
Cold weather burns more energy, as your body works to maintain warmth, while heat accelerates fluid and electrolyte loss. On a chilly February hike in the Peak District, you might find yourself craving denser foods such as flapjacks or nut butters, while a humid August trek across the South Downs could demand more fluids and electrolyte-based fuelling. Matching your supplies to seasonal conditions helps avoid energy dips.
It isn’t just weather that surprises: terrain has a way of amplifying fuelling needs. A flat 10-mile path may feel manageable on light snacks, but scramble routes or bog-heavy moors can easily double the perceived effort. Factoring in these terrain “multipliers” when packing food and drink helps prevent underestimating what you’ll use.
Unplanned bivouacs, getting benighted, or waiting for help after a twisted ankle all demand reserves. Compact, long-lasting items like energy bars or gels are ideal for this emergency margin, as they take up little space but provide quick energy and electrolytes when most needed.
Pack at least one extra fuelling option as a safety buffer
Match food and hydration to the forecast and temperature range
Consider terrain type and how it increases effort
Keep a small reserve set aside specifically for emergencies
Energy management outdoors isn’t just about what you eat or drink—it’s about timing, balance, and giving your body the occasional pause to reset. A smart approach weaves together fluids, food, and rest breaks so that stamina lasts across the whole outing rather than burning out early.
Rather than gulping large amounts of water at long intervals, sipping little and often keeps fluid levels steadier. Carrying bottles with clear markings helps track intake, while hydration bladders allow easy access without stopping. For longer efforts, alternating between plain water and drinks containing electrolytes ensures that both thirst and mineral balance are managed. Electrolyte gels can also supplement this balance without the bulk of extra bottles.
The body responds best to small, regular fuelling rather than large, infrequent meals. A flapjack bite every 45 minutes or a gel at the start of a steep climb can prevent dips before they begin. Think of snacks as fuel top-ups for your engine: consistent, measured, and planned rather than reactive to hunger pangs.
Stopping isn’t wasted time—it’s a chance to recharge. A short sit-down every couple of hours allows the body to process food, relax tightened muscles, and reset mentally. These pauses are ideal for eating more substantial items that are harder to manage on the move, such as wraps or savoury snacks. Choosing scenic spots can also lift morale, turning a functional break into a highlight of the day.
Energy and hydration work hand in hand. Eating without drinking can slow digestion, while drinking excessively without snacks may dilute blood sugar levels. A simple approach is to pair a small snack with a few sips of fluid every 30–45 minutes. This balanced cycle helps prevent slumps and avoids the extremes of dehydration or sudden fatigue.
Outdoor fuelling isn’t just about performance—it’s also about staying safe. Energy and hydration choices can directly affect decision-making, coordination, and even your ability to respond to emergencies. Treating nutrition as part of your safety kit ensures you’re better prepared for whatever the trail throws at you.
Low energy often shows up as poor balance, clumsiness, or slower reactions. On a rocky descent or exposed ridge, this can quickly become dangerous. Regular fuelling—whether with a snack, bar, or electrolyte gel—reduces the risk of slips caused by tired legs or clouded concentration.
While energy gels and other compact products are invaluable, relying on them exclusively can backfire. Some people experience stomach discomfort if they use them too frequently. Pairing these quick solutions with slower-release foods (nuts, oat-based snacks, savoury options) spreads the load and minimises risks of digestive upset.
Cold, wet conditions in the UK mean that food can become damp or spoil if not packed carefully. Wrap perishable items securely and avoid foods that degrade quickly in heat or rain. Sports gels and sealed packets offer a safer backup in case other items become inedible.
If travelling in a group, it’s wise to check that everyone is fuelling at a steady rate. The strongest hiker can still hit a wall if they neglect to eat or drink, slowing the whole party down or creating hazards. Encouraging regular breaks for shared snacks or hydration is both social and practical.
Carry a dedicated emergency reserve, kept separate from your main supply, to cover unplanned delays or injuries. This could be a couple of electrolyte gels, an energy bar, or other lightweight, high-calorie options. In an emergency, that small stash can make the difference between managing the situation calmly or facing unnecessary risk.
Outdoor fuelling is never one-size-fits-all. The combination of weather, terrain, distance, and personal preference makes each outing unique. By understanding how the body uses energy, preparing for unpredictability, and blending hydration with food and rest, you set yourself up for both performance and safety. Electrolyte gels, compact snacks, and simple homemade options each have their place; the art lies in mixing them wisely to suit the day.
For your next walk or climb, think beyond the map and kit list—consider fuelling as a vital piece of preparation. Ask yourself: do I have enough variety to keep energy steady, and a reserve in case of delays? With thoughtful planning, your snacks and drinks can become silent allies, helping you enjoy every mile with confidence.