Hiking and trekking nutrition: what to eat on the trail

Written by James Frost, founder of Flaming Phoenix and the maker of Phoenix Bars. Updated November 2026.

Quick answer: A long day of hiking with a pack burns roughly 3,000 to 5,000 calories, so eat 200 to 400 calories an hour on the trail, little and often, from compact food you can eat on the move, such as nuts, cheese, chocolate, flapjacks, dense bars and wraps. On multi-day treks, plan around 700g to 1kg of food a day and favour food with at least 4 calories per gram.

In this guide

• How many calories does hiking burn?
• Calories per gram and pack weight
• What makes a good hiking food?
• What to eat before and after a long hike
• How Phoenix Bars can be used
• What to pack by hike type
• Frequently asked questions

About this guide

This guide explains how to think about food for hiking and trekking, from day hikes to multi-day trails. It covers why calorie-dense, lightweight food matters, what to look for when choosing trail snacks, and how to avoid the mid-afternoon energy crash that ruins the last few miles.

For guidance on fuelling for ultra-distance events and expeditions, see the Ultra-Endurance and Expedition Nutrition Guide. For guidance on using Phoenix Bars across different situations, see How To Use Phoenix Bars.

I make Phoenix Bars, compact high calorie bars, so I have an interest here; the advice on this page applies whatever you carry.

Last reviewed: November 2026

Hiking is one of the most popular outdoor activities in the UK, and one of the most calorically demanding. A day on the fells, a coastal path walk, or a weekend in the mountains burns far more calories than most people realise. A full day of moderate hiking with a loaded pack can burn 3,000 to 5,000 calories, roughly double a normal day's intake.

Most hikers know they need to eat on the trail. Far fewer think carefully about what they eat and how many calories it actually provides. The result is predictable: strong start, good pace through the morning, then a steady decline in energy, mood, and leg power from mid-afternoon onwards. That last climb feels twice as hard as it should. The final miles drag. The car park cannot come soon enough.

More often than not, this is a calorie problem rather than a fitness problem. The food ran out, was not calorie-dense enough, or was not eaten consistently enough throughout the day.

This guide covers the basics of hiking nutrition for anyone who walks long enough and hard enough that food matters: day hikers, weekend walkers, long-distance trail walkers, and anyone planning a multi-day trek.

How many calories does hiking burn?

The numbers are higher than most people expect.

A person weighing 70kg hiking on moderate terrain with a light day pack burns approximately 400 to 500 calories per hour. Add elevation gain, a heavier pack, rough ground, or adverse weather and the figure rises to 500 to 700 calories per hour. Over a six-hour day, that is 2,400 to 4,200 calories for the hike itself, plus roughly 1,500 calories for the rest of the day.

The table puts those hourly figures into typical UK days out. Heavier hikers and heavier packs push the numbers up.

For a full day on a challenging route, total calorie need can reach 4,500 to 6,000 calories. On a multi-day trek, this adds up: a five-day hike can mean 10,000 to 18,000 calories more than you would use at home.

Most hikers bring a sandwich, some fruit, a cereal bar, and perhaps some trail mix. That might total 800 to 1,200 calories. The gap between what they burn and what they eat is enormous, and by mid-afternoon they feel it.

You do not need to match calorie burn exactly. Your body can draw on stored energy. But the closer you can get to replacing what you burn, the stronger and more enjoyable the day will be, especially in the final hours when most people are running on empty.

Calories per gram and pack weight

Calorie density is how many calories a food delivers per gram. On a hike, it determines two things: how many calories your food provides and how much weight you carry to get them.

An apple weighs about 180g and delivers roughly 95 calories. That is 0.5 calories per gram. A banana weighs about 120g and delivers roughly 105 calories. A standard cereal bar weighs 25 to 35g and delivers 90 to 130 calories. A Phoenix Bar has up to 557 calories in a compact, 120g bar, about 4.4 to 4.6 calories per gram depending on flavour.

The table shows how much of each common trail food you would carry for 2,000 calories, using typical UK label values. The figures are approximate and vary by brand.

The weight difference is significant when it is in your pack all day.

Calorie density also determines how much eating time is needed. Eating up to 557 calories from a single bar takes a fraction of the time and effort required to eat the same calories from multiple smaller snacks. Less time eating means more time walking.

For day hikes, the weight difference is a convenience. For multi-day treks where you carry all your food, it becomes a serious factor in pack weight and comfort. Our ranking of the lightest high calorie food for backpacking lists common trail foods by calories per gram.

What makes a good hiking food?

Not every food works well on the trail. The best hiking food balances calorie density with practicality. Our guide to the best energy bars for hiking puts the bars on UK shelves through the same tests.

High calories per gram. This is the primary criterion, especially for longer hikes and multi-day treks. More calories per gram means less weight for the same calories.

Does not spoil. Food that needs refrigeration or goes off quickly is impractical for anything beyond a short morning walk. Trail food needs to survive a full day in a pack, and ideally longer for multi-day trips.

Does not crush, melt, or fall apart. A sandwich squashed flat at the bottom of a rucksack is demoralising. Chocolate melted into a wrapper is annoying. Food that survives being packed, sat on, and carried all day without disintegrating is worth choosing.

Easy to eat on the move. The best hiking food can be eaten without stopping, without cutlery, and without creating mess. Unwrap, eat, walk. Anything that requires a plate, a spoon, or a ten-minute sit-down is a snack for a summit break, not trail fuel.

Keeps you going for hours. Sweets, gels and sugary drinks work fast but run out fast, so on their own they mean eating very often. Food that combines carbohydrates with fat and protein releases its calories over a longer stretch, so one snack carries you further up the hill.

Does not cause palate fatigue. On a long day, you need to keep eating. If your trail food is all intensely sweet, you will eventually stop eating it. A mix of flavours, or food with milder, less sweet profiles, sustains appetite across a full day.

What should you eat before and after a long hike?

Start with a carbohydrate-based breakfast two to three hours before you set off, such as porridge with fruit, or toast with jam or peanut butter. The American College of Sports Medicine's 2016 position statement suggests 1 to 4g of carbohydrate per kilogram of body weight in the one to four hours before exercise lasting more than an hour, which for a 70kg walker is 70 to 280g. Then start eating within the first hour of walking rather than waiting until you feel hungry.

Afterwards, a meal with carbohydrate and some protein within a couple of hours helps you recover for the next day. On a multi-day trek, the evening meal does this job, so make it the biggest of the day even when you feel too tired to cook.

How Phoenix Bars can be used

I make Phoenix Bars, so take this section as the maker's view. They fit hiking for the reasons above: up to 557 calories in a compact, 120g bar that survives a rucksack and stays easy to eat all day.

To carry the same calories in apples, you would need just over 1kg of fruit. Adam Eustace, bikepacking across Vancouver Island, found they didn't break up in his bag, and they can be eaten one-handed on the move. Add water and they become a camp porridge that replaces a stove meal.

It is a pressed oat bar, similar to a flapjack. The six flavours are mild rather than intensely sweet, which helps them stay appetising deep into a long day, when very sweet snacks start to lose their appeal.

On the move. Break a bar into pieces and eat them steadily over an hour or two. A full bar eaten gradually delivers up to 557 calories without needing to stop walking.

At a rest stop. Eat a whole bar or half bar alongside whatever other food you have brought. A Phoenix Bar and a flask of tea make a summit lunch of up to 557 calories, from a compact, 120g bar that takes up less pack space than a sandwich.

As a porridge. Adding water to a Phoenix Bar creates a calorie-dense porridge. You need a cup and water, and only the cup to rinse afterwards.

As an emergency reserve. A single Phoenix Bar in the bottom of your rucksack is up to 557 calories of emergency food that weighs less than a full 500ml water bottle, has a shelf life of up to two years, and is ready to eat immediately. If a hike takes longer than expected, the weather turns, or someone in the group runs out of energy, it is there.

"I enjoy Phoenix Bars whilst hiking as they are a great combination of being high in calories, tasty and lightweight. I like to use these specialist flapjacks on my tougher and longer hikes."

"I'm terrible at making sure I'm properly fuelled on long distance hikes, so finding these (especially as they're vegan) was a revelation! Tasted great, stayed in one piece in the bottom of my backpack until I needed a bite on the move."

Full nutritional information and ingredient lists for all six flavours are available on the product page.

What to pack by hike type

Day hike (3 to 5 hours, moderate terrain). You can afford to be relaxed. A Phoenix Bar to eat in pieces through the walk, some fruit, a sandwich for your lunch stop, and water. Total food weight well under 1kg. The bar provides a reliable calorie backbone; the rest is for variety and enjoyment.

Long day hike (6 to 10 hours, challenging terrain). Calorie needs are significant: 3,000 to 5,000 calories across the day. Pack two Phoenix Bars (up to 1,114 calories, 240g) alongside sandwiches, trail mix, and whatever else you enjoy. Eat one bar in portions through the morning and the second in the afternoon. This provides a consistent calorie base and saves the other food for the rest stops you look forward to.

Weekend or multi-day trek (2 to 5 days, carrying everything). This is where calories per gram start to decide your pack weight. Every extra gram of food weight is a gram on your back for the entire trip. For on-trail snacking, Phoenix Bars carry about 4.4 to 4.6 calories per gram, more than most snack bars and several times more than fresh food. Pack three to four bars per day for trail food (roughly 1,600 to 2,200 calories at 360 to 480g), supplemented by whatever you eat at camp. The porridge format means a bar plus water becomes a camp breakfast or dinner, reducing the need to carry separate stove meals.

Winter hiking (cold, wet, short daylight). Cold conditions increase calorie burn and suppress appetite. Food that stays soft in near-freezing temperatures and can be eaten with gloves matters. On the Winter Spine Challenger South, in temperatures around or below freezing, Christian Poulton found the bars stayed soft enough to eat when some of his other food was too hard. Short winter days are also when a good head torch and warm gloves earn their place, and both are in my guide to gifts for hikers and walkers if someone is asking what you would like for Christmas.

Overseas trekking (high altitude, multi-week, variable resupply). For treks where you carry food between resupply points, pack weight is critical. Phoenix Bars' shelf life of up to two years, compact size, and high calorie density make them practical for trips where resupply is uncertain. For altitude-specific guidance, see the High Altitude Mountaineering Nutrition page.

Related guides

• Ultra-Endurance and Expedition Nutrition Guide
• High Altitude Mountaineering Nutrition
• Cycling and Bikepacking Nutrition
• UK Ultra Race Nutrition
• How To Use Phoenix Bars
• Calorie-Dense Foods: What They Are and When They Help
• Arctic Circle Trail food
• Camino de Santiago food
• Haute Route Pyrenees food
• GR20 Corsica food

Frequently asked questions

How many calories do I need for a day hike?

A rough guide is to eat 200 to 400 calories per hour of hiking, depending on terrain, pack weight, and conditions. For a six-hour moderate hike, plan for roughly 1,200 to 2,400 calories of trail food on top of whatever you eat before and after. Many hikers underestimate this and wonder why they feel exhausted by mid-afternoon.

How much water should I drink on a hike?

A common starting point is about half a litre an hour in mild weather, and more in heat or on long climbs. The American College of Sports Medicine's guidance aims to keep sweat losses below about 2% of body weight, about 1.4kg for a 70kg hiker, so weighing yourself before and after a long walk shows whether you drank enough. In the UK hills, a filter or purification tablets let you refill from streams instead of carrying it all.

What is the best food to carry for weight?

Per gram, the lightest calories you can carry are nuts and nut butters, at about 6 calories per gram, followed by chocolate at about 5.5. Trail mix, flapjacks, cheese and dense bars sit at about 4 to 4.8, while a standard cereal bar delivers 3 to 4 and fresh fruit under 1. The table in the calories per gram section above shows the weight of each for 2,000 calories.

Do Phoenix Bars work in hot and cold weather?

Customers who have used them at both extremes say yes. One found them easy to eat at -45°C on a South Pole expedition, and a Marathon des Sables runner said they kept their shape even in desert temperatures. Chocolate-coated bars and plain chocolate are the ones to keep out of a hot side pocket.

Can Phoenix Bars replace a meal on a multi-day trek?

A single Phoenix Bar delivers up to 557 calories, up to 66g of carbohydrates and up to 19g of protein. That is comparable to a substantial meal. Made into porridge with full-fat milk or water, it can serve as a camp breakfast or dinner. Pair it with your other trail food and camp meals for variety across the trek.

How many Phoenix Bars should I take on a multi-day trek?

As a rough guide, budget two to four bars per day depending on how much other food you carry. For a three-day trek with limited resupply, ten bars give up to 5,570 calories of shelf-stable, no-cook trail food in 1.2kg. At 3,000 to 5,000 calories a day, that covers roughly a third to three-fifths of what you will burn over the three days, with camp meals making up the rest.

Buy Phoenix Bars

If you have any questions about using Phoenix Bars for hiking or trekking, contact me directly. I am always happy to help.

Written by James Frost, founder of Flaming Phoenix and the maker of Phoenix Bars.

jfrost@flaming-phoenix.co.uk

07990 519422

Sources: American College of Sports Medicine, Academy of Nutrition and Dietetics and Dietitians of Canada, Joint position statement on nutrition and athletic performance (2016); typical UK pack label values for the calories-per-gram table.