Having enough calories on a long hike is essential. Usually, on trips shorter than 1 week long, I don't pay much attention to my calorie intake. For longer hikes though, I make sure I have plenty of calories. A deficit of 1000 calories a day will make you lose roughly 1lb/week. So it can be an issue when you hike weeks and months at the time. Losing too much weight would result in a lack of energy, malnutrition, and might ultimately end your adventure. When you are hiking long distances, you must eat food whether you are hungry or not.
How you burn calories depends greatly on how you push yourself, your age, your weight, etc. If I take myself for example, on hard days (12h+), I easily burn 5000+ calories. The following information is based on a stoveless hiker diet, which means no food is cooked on the trail.
Here are two rules I follow when I plan my food for long-distance hiking.
Have a snack or a small treat for every hour hiked: So if you plan to hike an average of 10h per day. You should plan 10 treats a day. Having a constant intake of calories and carbs will keep your energy level up.
Have a "meal" every 3h: if we take the usual 10h hike. You would have 4 meals (one at 0h, 3h, 6h, and 9h). If you would hike 12h you would have 5 meals, and so on. Those meals are usually 100 grams. Breaks are a great time to enjoy the scenery, dry stuff if needed, and enjoy some good food.
When it comes to lightweight high in calories food, healthy food is not really a livable option. Fresh food is filled with water (which adds lots of weight). If you have the chance to put your hand on a dehydrator, you can remove the exceeding water of any food, and saving ~90% of its weight. But when thru-hiking, I don't have a dehydrator with me so here is a short list of some food I use while hiking long distance. Snacking: When it comes to snacks, I'm a huge fan of bars, it is easy to carry (in your pockets or backpack belt pockets), easy to calculate, and plenty of options and flavours to choose from.
Meals: In the morning, I often want to be moving (especially if it's chilly), so I usually eat things that I can snack easily while being on the move. My midday meals are alternated between sweet and salty (or a bit of both when the day has been rough).
A mix of dry fruits
Chocolate (dark chocolate come to me!)
Did I mention chocolate?
Before bed: The last meal I eat before bed is usually different than during the day. I don't want to have something too salty that will make me drink all night. Nothing too sweet that will keep me awake. I need a decent amount of fat and calories to stay warm and protein to help my muscles overnight. (Consider doubling this meal in winter, the extra calories will help to keep you warm overnight.)
Plain nuts with a few dry fruits (my long-time favourite)
Unsalted seeds (Sunflower, Hemp, etc..)
Crunching the Numbers
Now, it's time to test how good is my math. I will try to keep it simple for both our shakes. (The last thing I want is to see blood coming out from my nose, from too much brain work.) Base on a 10h hiking day:
Rule 1: That was the 1 bar/hour rule. I will only state a few examples here.
Lara Bar (200 cal / 45g)
Cliff Bar (250 cal / 68g)
Snickers (280 Cal / 57g)
Granola Bar (190 Cal / 42g)
On average we are looking at a 230cal and 53g per bars. Total Calories: 2300 (230cal x 10h) Total Weight: 530g (53g x 10h)
Rule 2: One meal every 3 hours. Here are a few examples:
Dark Chocolate (520 cal / 100g)
Banana chips (515 cal / 100g)
Sesame Sticks (510 cal / 100g)
Trail mix (475 cal / 100g)
Chips (530 cal / 100g)
Mix nuts (600 cal / 100g)
Plain biscuit (360cal / 100g)
In average we are looking at 500 cal / 100g Total Calories: 2000 (500 x 4) Total Weight: 400g (100g x 4)
Grand Total = 4,300 cal for 930g / day As you can see, for about 1kg of food per day, you can ensure you have plenty of calories and food to keep your energy and muscles sustained for 10 straight hours. Those two rules can be applied for 7h hike days or 14h days, everyone is different. By simply using these two rules you can create your own food plan. Also, these rules are not set in stones. If you rather have a meal every 4h, or fewer bars and bigger meals. Feel free to adapt it to your liking.
What about fresh food? I eat fresh food any chance I got. When I resupply I always buy lots of veggies and fruits and eat all day (if I take a rest day), or on the spot (if I'm moving on right away). Most of the stated food above is not the healthiest, but it's extremely hard to find healthy food that is packed with calories to keep the weight relatively down. I know a watermelon would be incredible up a peak! Try carrying one once and you will understand what I mean.
In long-distance hiking, we often refer to "hiker's hunger" the feeling of constantly being hungry. This shouldn't happen if you follow these two simple rules and adapt them to your exercise level and trail condition. By so, you ensure you are well fed and have plenty of energy to push yourself and enjoy the outdoor. (Talking about food, I'm hungry now! Aren't you?) Happy food, Happy mood! and bon appétit!